Post by thread:[EE] Etching PCBs

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'[EE] Etching PCBs - Danger?'
2009\01\22@214319 by solarwind

This dude gives a nice, simple guide to etching PCBs - http://more.random.stuff.googlepages.com/howtomakepcbs Looks nice and simple and the results are perfect. However, the guys at systm http://revision3.com/systm/etching/ give a lot of safety tips and make it sound like a very risky job. What do you guys think? -- solarwind

2009\01\22@223217 by Sean Breheny

Well, I listened to about half of the video in the second link and those guys are annoying and exaggerate the danger somewhat. The two most common chemicals used are Ferric Chloride solution and Ammonium Persulfate solution. Neither of them is a strong acid (as they state again and again in the video). They are dangerous, but for different reasons. Ferric Chloride (let's call it FC) tends to work faster than Ammonium Persulfate (call it AP) in my experience. FC is a dark liquid which becomes opaque as it becomes filled with copper, whereas AP is initially colorless and becomes blue-green as it reacts with the copper. This has the advantage that you can see the progress without removing the PCB from the solution. FC is very corrosive to most metals - staining them permanently or even eating them away, as it does to copper. It is definitely poisonous if you drink it or inhale its vapor in significant quantities. The main danger here, I think, is burns to the membranes in your respiratory or digestive system from the corrosive reaction (which is NOT the same thing as an acid reaction). If you get it on your skin, it will stain and dramatically dry out your skin in the affected area, but you are unlikely to suffer any burns if you wash it off within a minute or two. If you get it on clothing, you will never be able to get the stain out. I have gotten a few drops of it on my skin many times and I can no longer see any evidence of the stains, nor did I experience any pain or other problems. Dry FC is perhaps even more dangerous because it is deliquescent - it absorbs water vapor from the air until there is enough water to dissolve the FC, which then becomes a super concentrated solution. My cat once licked a little bit of this from a stain on the floor and vomited immediately. I didn't find out until much later but he suffered no lasting problems that I can tell - although he probably didn't take much of it in. I have less experience with AP but I'd say that it is less harmful if you get it on your skin. It is less "aggressive" in general at eating away at things. The downside of this is that it does not etch well at all unless you warm it and agitate it. If you just let a PCB sit in room temp FC, it will etch in perhaps 45 minutes. It would take many hours in AP. If you warm them to say, 50C, and agitate with bubbles from a fish-tank air pump, the FC will etch the board in about 3 minutes and the AP in about 10 minutes. Both FC and AP really should be warmed and agitated during etching to ensure even coverage and relatively quick etching time. Long etching times not only make you impatient but they also can allow the resist material to begin to come off. Agitation has to be done very carefully to avoid spraying warm FC or AP around. Since most drain plumming is PVC and not metal, as far as I know, you can dispose of small amounts (perhaps, say, 500mL or less) at a time into the toilet in a normal sewer system. Probably not a good idea for septic systems. It is very important to dilute it GREATLY before disposal. I usually would pour about 50mL at a time into the toilet bowl and then flush, then repeat. Then I would follow this up with several buckets full of water. This is to avoid staining of pipes/toilet bowl, any corrosion of metal parts that I may not be aware of in the system, and to help guarantee that by the time it arrives at any processing facility, it has been very much diluted. Strictly speaking, you are probably supposed to take FC and AP to a hazardous waste facility but I have never done that. I only used perhaps 1 liter of it per year. To use FC or AP, I would recommend safety glasses, a closed container for your etchant tank so that splashing doesn't happen, and good ventilation. If you were to do this on a daily basis, then I think you would probably need a vent hood to limit chronic exposure. I would say, though, that in the end, etching your own PCBs is not worth it anymore for most people. PCB houses have become so inexpensive and have relatively fast turn-around. Also, to produce something anywhere near as nice-looking as a PCB house will take considerable time, effort, and money. This is not even considering things like plated-thru holes, soldermask or silkscreen, or more than 2 layers. Sean On Thu, Jan 22, 2009 at 9:42 PM, solarwind <spam_OUTx.solarwind.xTakeThisOuTgmail.com> wrote: {Quote hidden}> This dude gives a nice, simple guide to etching PCBs - > http://more.random.stuff.googlepages.com/howtomakepcbs > > Looks nice and simple and the results are perfect. > > However, the guys at systm http://revision3.com/systm/etching/ give a > lot of safety tips and make it sound like a very risky job. > > What do you guys think? > > -- > solarwind > -

2009\01\22@223249 by peter green

solarwind wrote: > This dude gives a nice, simple guide to etching PCBs - > http://more.random.stuff.googlepages.com/howtomakepcbs > > Looks nice and simple and the results are perfect. > > However, the guys at systm http://revision3.com/systm/etching/ give a > lot of safety tips and make it sound like a very risky job. > > What do you guys think? > I think they were exagerating on the strength of the stuff used to etch PCBs, if it were really as bad as they made out then I would expect to see much more protective equipment used when handling it. I took a look to see just how hazardous ferric chrloride (the most common etchant among hobbyists afaict) is. Here are a couple of links I found. www.rapidonline.com/netalogue/specs/34-0758h.pdf http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc14/icsc1499.htm They give the impression that it's not the sort of stuff you want to get on your hands if you can help it but it's not horriblly dangerous either. It is VERY corrosive towards most metals though ;)

2009\01\22@230745 by solarwind

I have not found a single PCB manufacturer with good prices. I can, however, get the chemicals and agitation tank for making my own PCBs for a very low cost and copper clad board is practically free. After that, one can make any pcb at any size, good for hobby projects. If I can get a full PCB under $20 from a PCB house, I'll go for it, but anything more than that is expensive.

2009\01\22@231342 by solarwind

The cheapest I found was BatchPCB from Sparkfun. Setup fee - $10 Cost - $2.50 / sq in + Shipping So thats $10 + $30 + shipping for a 4 x 3 board. Wayyy too expensive.

2009\01\22@232319 by Bob Blick

solarwind wrote: > This dude gives a nice, simple guide to etching PCBs - > more.random.stuff.googlepages.com/howtomakepcbs > > Looks nice and simple and the results are perfect. Not perfect. I used to teach electronics and we made lots of PC boards, the laser printer method was the least perfect. Quite often "good enough" though. Everyone should make their own PC boards at least enough times to find out where their skill/comfort level is. > However, the guys at systm http://revision3.com/systm/etching/ give a > lot of safety tips and make it sound like a very risky job. If it was so risky then Radio Shack wouldn't sell etchant. There is very little danger to you, but try not to spill it on metal you care about. And when you heat it, be aware that any metal nearby will corrode. If you heat it in a microwave oven, put a sealed baggie over the container so the vapors don't ruin your microwave. Cheers, Bob

2009\01\22@232458 by Jinx

> FC is very corrosive to most metals - staining them permanently Works on shirts too. Nothing gets FeCl stains out. Look Seriously, I've never felt in danger whilst etching. More worried about spashing hot water out of the jacket actually > AP is initially colorless and becomes blue-green as it reacts with > the copper. This has the advantage that you can see the progress > without removing the PCB from the solution My technique is to etch the board umop 3pisdn http://home.clear.net.nz/pages/joecolquitt/0makepcb.html > If you just let a PCB sit in room temp FC, it will etch in perhaps > 45 minutes New solution with a hot water jacket - 7, 8 minutes. Once it gets past 15 minutes it's time t'go. For one thing, long etching times runs the risk of under-cutting the resist. At best it can feather the edges of tracks, a problem with thin ones of course, at worst the etchant can be there long enough to creep under the resist and etch out any low spots, eg scratches in the copper, resulting in very fine 'cuts' across the track. Tinning will usually fix that

2009\01\22@233042 by Bob Blick

solarwind wrote: > I can, > however, get the chemicals and agitation tank for making my own PCBs Agitation tank? Why not just jiggle the Tupperware by hand while you read or surf the net? -Bob

2009\01\22@234711 by John Day

At 11:30 PM 1/22/2009, you wrote: >solarwind wrote: > > I can, > > however, get the chemicals and agitation tank for making my own PCBs > >Agitation tank? Why not just jiggle the Tupperware by hand while you >read or surf the net? For years I used a plastic "lunchbox" with a pencil under it so that I could rock it! John >-Bob >

2009\01\22@234905 by William \Chops\ Westfield

On Jan 22, 2009, at 8:13 PM, solarwind wrote: > The cheapest I found was BatchPCB from Sparkfun. > : > So thats $10 + $30 + shipping for a 4 x 3 board. Wayyy too expensive. Yeah, well. That $40 will get you a lot nicer board than you'll be able to achieve at home for any similar cost of materials... Good Luck. (hey, I spent a small fortune on PCB making machines so I wouldn't have to use "expensive" fabs as well. So I know the feeling. (I'm still not sure that I made a sound economic decision. (Though since it's a hobby, economics has little to do with it.))) BillW

2009\01\22@234926 by solarwind

On Thu, Jan 22, 2009 at 11:30 PM, Bob Blick <.....bobblickKILLspam@spam@ftml.net> wrote: > solarwind wrote: >> I can, >> however, get the chemicals and agitation tank for making my own PCBs > > Agitation tank? Why not just jiggle the Tupperware by hand while you > read or surf the net? > > -Bob LOL! I want to build a simple tank with a heater because I want to make PCBs often for my projects. I hate breadboards. And PCBs are nice and easy to make. Drilling doesn't take too long and the tools needed to etch are very inexpensive. How much does a bottle of the etchant cost? How many PCBs can one etch with it? Approx. -- solarwind

2009\01\22@235857 by Jinx

> Agitation tank? Why not just jiggle the Tupperware by hand while > you read or surf the net? I used to think about making a motorised wobbler or an aerator. But then decided etching upside down with good etchant doesn't need any help really, so I never bothered

2009\01\23@000546 by John Day

At 11:13 PM 1/22/2009, you wrote: >The cheapest I found was BatchPCB from Sparkfun. > >Setup fee - $10 >Cost - $2.50 / sq in >+ Shipping > >So thats $10 + $30 + shipping for a 4 x 3 board. Wayyy too expensive. Well, you have to decide your own comfort level and your own value. $40 plus shipping is way less than anything I have had done for years, so yes, it is very low cost. It just may not be the value you are seeking. For double sided plated through with solder mask and silk-screen good value is about $160 for a batch, this can be anywhere form 25 to 50 boards depending on size. So if I do my job well the prototype batch is also the first production batch. The Sparkfun system is VERY good value. They panelise the boards and then the setup and photo-tooling and silk screen costs are split amongst a number of users. Typically the NRE (non-recurring engineering) for a small panel is around $68 (in China, way more in North America). For a 2x4" board I will end up paying $1.47 each for 25 boards or maybe $4 for just one, plus $68 for NRE. Given the value of my time this is an absolute bargain! If your time is worth nothing to you, then this is expensive. As a further example of the China/North America comparison. The other day I needed a few fast turned 4 layer boards. The PCB is 1.8x3.3", for five pieces I was quoted $750 from one house, $550 from another both offering 5 business day turn-around, plus shipping and shipping delay. My favourite Chinese board house received the gerbers and payment at about 3pm EST on Wednesday Jan 14th. The finished boards arrived via Fedex during the day of the 20th. The fifth working day. And the cost? A mere $320 USD including, NRE, bare board test, test set-up and Fedex delivery. John >

2009\01\23@000808 by Bob Blick

solarwind wrote: > How much does a bottle of the etchant cost? How many PCBs can one etch > with it? Approx. Radio Shack stuff is pretty watered down. If you can find it dry you'll know what you are getting. Use cold water because it gets HOT when you mix it. http://www.elexp.com/pro_3er3.htm If that link works, they say 1 pint does 200 square inches, so $12 of dry etchant is enough for 800 square inches. Also, fishtank heaters are not very strong. If your etchant is cold you will need to heat it up some other way, the fishtank heater can only keep it warm for a while. We kept our "system" in a big styrofoam icechest and had two fishtank heaters and an air pump for bubbles. Cheers, Bob

2009\01\23@001209 by John Day

At 12:57 AM 1/23/2009, you wrote: > > Agitation tank? Why not just jiggle the Tupperware by hand while > > you read or surf the net? > >I used to think about making a motorised wobbler or an aerator. But >then decided etching upside down with good etchant doesn't need any >help really, so I never bothered To get a good clean etch you should be gently circulating the etchant so that the surface you are working on is always exposed to fresh material. If you look at a board etched with no agitation you will see undercut - the edges of the copper are undermined. On fine tracks this can result in a serious loss of width and detail. John >

2009\01\23@001707 by Jinx

> If that link works, they say 1 pint does 200 square inches, so $12 > of dry etchant is enough for 800 square inches. You can improve that by not etching areas that don't need to be, ie fat traces & filling in with resist

2009\01\23@002000 by solarwind

On Fri, Jan 23, 2009 at 12:07 AM, Bob Blick <bobblickKILLspamftml.net> wrote: > If you can find it dry you'll know what you are getting. Use cold water > because it gets HOT when you mix it. > > http://www.elexp.com/pro_3er3.htm > > If that link works, they say 1 pint does 200 square inches, so $12 of > dry etchant is enough for 800 square inches. For $12 I can etch 800 sq in? Now THAT's a bargain! I'm not "cheap", I'm just a student and doing this as a hobby so I don't have hundreds of dollars to spend on a pass-time like you professionals. You guys do this for a living and may have unlimited funding from your company even. I don't. I just have a few dollars from extra lunch money, lol. So The difference between a few cents for copper clad and $10 to etch all the boards I'll ever need vs $40 per board + waiting time is a huge difference to me. Time IS a value to me. If you put it that way - the time it takes for me to send in my design to the time it arrives at my house may be a week. In comparison, I can have a fully made PCB in about half an hour. 10 minutes to print out and iron it on. 20 minutes to soak it in soapy water and peel off paper. 5 minutes to etch it in a hot, agitated solution of etchant. 5 - 10 minutes to clean it. Now, if I obviously can't do 4 layer PCBs, but double sided shouldn't be any harder than single sided. Just have to iron both sides, don't I? And that's probably all I'll ever need. And judging from the results from pictures, the results seem better than what everyone is saying. -- solarwind

2009\01\23@002011 by Jinx

> >I used to think about making a motorised wobbler or an aerator. But > >then decided etching upside down with good etchant doesn't need any > >help really, so I never bothered > > To get a good clean etch you should be gently circulating the etchant I used to do the opposite. Twirl the floating board. But as the contaminated etchant sinks it creates its own eddies, so I don't even do that anymore Man, it's the sweet lazy life being an etcher around here ;-)

2009\01\23@002212 by solarwind

On Fri, Jan 23, 2009 at 12:11 AM, John Day <.....john.dayKILLspam.....siliconrailway.com> wrote: > To get a good clean etch you should be gently circulating the etchant > so that the surface you are working on is always exposed to fresh > material. If you look at a board etched with no agitation you will > see undercut - the edges of the copper are undermined. On fine tracks > this can result in a serious loss of width and detail. > > John Yeah. I'm thinking about putting two fish tank bubblers on overdrive and a heater coil to keep the solution at a certain temperature. Hey, maybe I can make my own PCB and circuit to control temperature and timing of solution :) I can probably even make a system to sound an alert after the etching time has completed. -- solarwind

2009\01\23@002447 by solarwind

On Fri, Jan 23, 2009 at 1:15 AM, Jinx <EraseMEjoecolquittspam_OUTTakeThisOuTclear.net.nz> wrote: >> If that link works, they say 1 pint does 200 square inches, so $12 >> of dry etchant is enough for 800 square inches. > > You can improve that by not etching areas that don't need to be, ie > fat traces & filling in with resist > $12 for 800 sq in. BatchPCB's prices are $2.50 / sq in so the equivalnt cost to have this done at BatchPCB is 800 x 2.5 = a spanking new expensive laptop for me. -- solarwind

2009\01\23@004347 by Bob Blick

solarwind wrote: > Now, if I obviously can't do 4 layer PCBs, but double sided shouldn't > be any harder than single sided. Just have to iron both sides, don't > I? It's fine for crude stuff. But you can't get all four corners to register exactly. Also, laser printers go faster and slower as the paper goes through. So even if you could get all four corners to line up, in between there would be registration errors between the two sides. But if you are careful you can do coarse stuff on smallish boards. Hey, go for it. You will see what the limitations are and if you're doing the layout yourself you can design accordingly. Use big vias with room around them. Or get good at drilling slanted holes :) Best regards, Bob

2009\01\23@012823 by Jesse Lackey

Double-sided homebrew... PITA. I wish you luck, IMHO you're pretty naive about what it is going to take to do better than simple boards. However if you're more excited about the craft of it all than doing more sophisticated designs then by all means go for it... At one point I had a custom laminator and laserprinted resist on special paper and a dremel with different bit sizes and drill press and etchant solution and steel wool scrubbers and rubber gloves and so forth. Not worth it. Saved the dremel and drillpress, gave all the other stuff away. barebonespcb.com is all I ever do when I don't need "real" boards. 1 day turnaround, pay per square inch, and with the "gerbmerge" program I can take multiple gerbers from Eagle designs and merge together into a single order. I just did a personal project (qty 1), and two client projects (qty 4 and qty 5) in one 13.5" x 6.8" panel, overnight fedex, $132. The biggest advantage of barebonespcb is that you can design with "normal" rules, not wider everything to make homebrew possible. 20 mil SMT pin pitches? No problem. But as always there is the time/money tradeoff, though in this case DIY will never be as good as what they do, unless you buy all the professional gear a boardhouse has. J solarwind wrote: {Quote hidden}> On Fri, Jan 23, 2009 at 12:07 AM, Bob Blick <bobblickspam_OUTftml.net> wrote: >> If you can find it dry you'll know what you are getting. Use cold water >> because it gets HOT when you mix it. >> >> http://www.elexp.com/pro_3er3.htm >> >> If that link works, they say 1 pint does 200 square inches, so $12 of >> dry etchant is enough for 800 square inches. > > For $12 I can etch 800 sq in? Now THAT's a bargain! > > I'm not "cheap", I'm just a student and doing this as a hobby so I > don't have hundreds of dollars to spend on a pass-time like you > professionals. You guys do this for a living and may have unlimited > funding from your company even. I don't. I just have a few dollars > from extra lunch money, lol. So The difference between a few cents for > copper clad and $10 to etch all the boards I'll ever need vs $40 per > board + waiting time is a huge difference to me. > > Time IS a value to me. If you put it that way - the time it takes for > me to send in my design to the time it arrives at my house may be a > week. In comparison, I can have a fully made PCB in about half an > hour. > > 10 minutes to print out and iron it on. > 20 minutes to soak it in soapy water and peel off paper. > 5 minutes to etch it in a hot, agitated solution of etchant. > 5 - 10 minutes to clean it. > > Now, if I obviously can't do 4 layer PCBs, but double sided shouldn't > be any harder than single sided. Just have to iron both sides, don't > I? And that's probably all I'll ever need. And judging from the > results from pictures, the results seem better than what everyone is > saying. > > >

2009\01\23@015011 by solarwind

On Fri, Jan 23, 2009 at 1:27 AM, Jesse Lackey <@spam@jsl-mlKILLspamcelestialaudio.com> wrote: > Double-sided homebrew... PITA. > > I wish you luck, IMHO you're pretty naive about what it is going to take > to do better than simple boards. However if you're more excited about > the craft of it all than doing more sophisticated designs then by all > means go for it... IMHO you're severely underestimating what can be done with homebrew double sided. I don't care how much experience you have. I've seen "experienced" people make some stupid mistakes consistently throughout their career. Remember that thread about the EE who taught people to cold solder joints? Ya. I have no experience doing it but I've seen my teacher's end result on a home brew double sided toner transfer PCB. It was pretty complex and came out very well, way more than what I had expected. I was impressed. > At one point I had a custom laminator and laserprinted resist on special > paper and a dremel with different bit sizes and drill press and etchant > solution and steel wool scrubbers and rubber gloves and so forth. > > Not worth it. Saved the dremel and drillpress, gave all the other stuff > away. Cool! > barebonespcb.com is all I ever do when I don't need "real" boards. 1 > day turnaround, pay per square inch, and with the "gerbmerge" program I > can take multiple gerbers from Eagle designs and merge together into a > single order. I just did a personal project (qty 1), and two client > projects (qty 4 and qty 5) in one 13.5" x 6.8" panel, overnight fedex, $132. > > The biggest advantage of barebonespcb is that you can design with > "normal" rules, not wider everything to make homebrew possible. 20 mil > SMT pin pitches? No problem. $50 for a 3 x 4? You gotta be kidding, right? See, you're JOB forces you to get this stuff done professionally. You don't want to be constantly etching your own PCB. Besides, what will your clients think? > But as always there is the time/money tradeoff, though in this case DIY > will never be as good as what they do, unless you buy all the > professional gear a boardhouse has. > > J Of course it wont be as good, but it'll be good enough. -- solarwind

2009\01\23@042512 by apptech

> I can probably even make a system to sound an alert after the etching > time has completed. The prior :-) noted - but, most home etching of PCBs of any complexity benefits greatly from having an eye and brain in the control loop. Of course, real men use Pirhana, which etches faster than most people can think. Is it done? Maybe not. Is it done? Just about! Is it done? Oh bother!!! Use outside. Ventillate well. Have paid up insurance. Fun though. Russell

2009\01\23@045519 by peter green

> Now, if I obviously can't do 4 layer PCBs, but double sided shouldn't > be any harder than single sided. Afaict homemade double sided is a PITA for two reasons The first is alignment, with a single sided board you really don't need to do any particularlly accurate alignment of your design. with double sided you have to find a way to line up the patterns on the two sides. Secondly your board wont be PTH, that means whenever a track leaves a pad on the top layer you need to solder the component on the top layer and whenever you have a via you need to put a peice of wire through it and solder it on both sides.

2009\01\23@054354 by Jinx

> Afaict homemade double sided is a PITA for two reasons I've done many double-sided boards at home by hand, most a mix of SMT and through-hole. Having a couple of reference positions to measure from is usually all that's necessary, and you double-check as you go. Quite reasonable results can be had if you accept some limitations and aren't too ambitious One I'm working on now has an array of through-hole tact switches on one side, mounted SMT-style, plus SOIC logic, diodes and SMT caps/resistors. On the other side is an 18F, DIP, but mounted SMT-style and assorted through-hole and SMT components There aren't a lot of inter-layer connections needed for this particular circuit. The tact switches and their debounce/buffer logic are in one area of one side, with only the outputs of the gates needing to go through the board to the PIC, and they're arranged to do that through the pins of a SIL resistor array The point I'm trying to make is that through-hole components don't actually have to go through holes. One advantage of not drilling is of course that you aren't intruding into useable area on the other side. Plus it reduces the size of the board, having components on both sides

2009\01\23@063106 by Carl Denk

Caution, in addition to the usual healthy warnings, the etching process generally liberates chlorine gas. Good ventilation is a must, but might not be sufficient! My workshop has a good exhaust fan, plus being a fairly open area. Several days after etching a few small boards, I noticed rust forming on just about any bare steel in the workshop including some very nice tools and good supplies. It was quite a project to go through everything, remove the rust, some of it was getting to the flaking stage within less than a week. Chlorine combines with the iron >> FECL (might have some of the subscripts wrong) >> + H2O >> Rust + Chlorine liberated. The Chlorine then is free to do it all over again! Best to do it outside, UGH, it's been below 0F here for several nights. Jinx wrote: >> Afaict homemade double sided is a PITA for two reasons >> > > I've done many double-sided boards at home by hand, most a > mix of SMT and through-hole. Having a couple of reference > positions to measure from is usually all that's necessary, and you > double-check as you go. Quite reasonable results can be had > if you accept some limitations and aren't too ambitious > > One I'm working on now has an array of through-hole tact > switches on one side, mounted SMT-style, plus SOIC logic, > diodes and SMT caps/resistors. On the other side is an 18F, > DIP, but mounted SMT-style and assorted through-hole and > SMT components > > There aren't a lot of inter-layer connections needed for this > particular circuit. The tact switches and their debounce/buffer > logic are in one area of one side, with only the outputs of the > gates needing to go through the board to the PIC, and they're > arranged to do that through the pins of a SIL resistor array > > The point I'm trying to make is that through-hole components > don't actually have to go through holes. One advantage of not > drilling is of course that you aren't intruding into useable area > on the other side. Plus it reduces the size of the board, having > components on both sides > > KILLspampiclist-ownerKILLspammit.edu wrote: {Quote hidden}> The message's content type was explicitly disallowed > > > > ------------------------------------------------------------------------ > > Subject: > Re: [EE] Etching PCBs - Danger? > From: > Carl Denk <RemoveMEcdenkTakeThisOuTalltel.net> > Date: > Fri, 23 Jan 2009 06:15:58 -0500 > To: > "Microcontroller discussion list - Public." <spamBeGonepiclistspamBeGonemit.edu> > > To: > "Microcontroller discussion list - Public." <TakeThisOuTpiclistEraseMEspam_OUTmit.edu> > > > Caution, in addition to the usual healthy warnings, the etching process > generally liberates chlorine gas. Good ventilation is a must, but might > not be sufficient! My workshop has a good exhaust fan, plus being a > fairly open area. Several days after etching a few small boards, I > noticed rust forming on just about any bare steel in the workshop > including some very nice tools and good supplies. It was quite a project > to go through everything, remove the rust, some of it was getting to the > flaking stage within less than a week. Chlorine combines with the iron > >> FECL (might have some of the subscripts wrong) >> + H2O >> Rust + > Chlorine liberated. The Chlorine then is free to do it all over again! > Best to do it outside, UGH, it's been below 0F here for several nights. > > Jinx wrote: >>> Afaict homemade double sided is a PITA for two reasons >>> >> >> I've done many double-sided boards at home by hand, most a >> mix of SMT and through-hole. Having a couple of reference >> positions to measure from is usually all that's necessary, and you >> double-check as you go. Quite reasonable results can be had >> if you accept some limitations and aren't too ambitious >> >> One I'm working on now has an array of through-hole tact >> switches on one side, mounted SMT-style, plus SOIC logic, >> diodes and SMT caps/resistors. On the other side is an 18F, >> DIP, but mounted SMT-style and assorted through-hole and >> SMT components >> >> There aren't a lot of inter-layer connections needed for this >> particular circuit. The tact switches and their debounce/buffer >> logic are in one area of one side, with only the outputs of the >> gates needing to go through the board to the PIC, and they're >> arranged to do that through the pins of a SIL resistor array >> >> The point I'm trying to make is that through-hole components >> don't actually have to go through holes. One advantage of not >> drilling is of course that you aren't intruding into useable area >> on the other side. Plus it reduces the size of the board, having >> components on both sides >> >>

2009\01\23@065340 by olin piclist

solarwind wrote: > This dude gives a nice, simple guide to etching PCBs - > http://more.random.stuff.googlepages.com/howtomakepcbs > > Looks nice and simple and the results are perfect. > > However, the guys at systm http://revision3.com/systm/etching/ give a > lot of safety tips and make it sound like a very risky job. > > What do you guys think? I think etching your own boards isn't worth it. I also don't want to waste time dealing with no plated thru holes, screwups due to lack of silkscreen, and no solder mask. Commercially made prototype PC boards are cheap and widely available. The tradeoffs may be a little different for hobbyists, but all the hassle and downside of self-made boards still apply. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000.

2009\01\23@071206 by olin piclist

solarwind wrote: > The cheapest I found was BatchPCB from Sparkfun. > > Setup fee - $10 > Cost - $2.50 / sq in > + Shipping > > So thats $10 + $30 + shipping for a 4 x 3 board. Wayyy too expensive. Not at all. Etching your own boards isn't free either. Show your parents what you're up to, show them that you've done your homework by looking around at how to get PC boards made, the best deal you've found, and see if they'll give you the money or order the boards for you. A few 10s of $$ is really a drop in the bucket compared to the cost of raising a kid. If they know the money is furthering your education as apposed to you going out and goofing off with it with your friends, I suspect you'll find them supportive. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000.

2009\01\23@072325 by Jinx

> the etching process generally liberates chlorine gas I can honestly say I've never smelled chlorine whilst etching. My guess would be that chlorine ions that don't bond with the copper will go into solution And just checking that http://en.wikipedia.org/wiki/Ferric_chloride FeCl3 + Cu ? FeCl2 + CuCl FeCl3 + CuCl ? FeCl2 + CuCl2 The brown sludge left over would be the mix of iron and copper chlorides. ISTR that electrolysis could recover the copper and convert some of the Fe(II) chloride back to Fe(III) chloride

2009\01\23@080157 by William \Chops\ Westfield

On Jan 23, 2009, at 5:21 AM, Jinx wrote: >> the etching process generally liberates chlorine gas > > I can honestly say I've never smelled chlorine whilst etching Me either, and I find the chemistry a bit questionable. But the "everything metal in the workshop starts to rust" effect seems to be pretty real. (Even the "stainless steel"!) I've always assumed that it's due to microscopic droplets of etchant solution made airborne by the bubbler-style agitation. (Hmm. Still a good reason for adequate ventilation!) BillW

2009\01\23@081845 by Jinx

> "everything metal in the workshop starts to rust" effect seems to > be pretty real Oh yeah, it'll eat anything. The fumes or "smell" of it permeates across the bench and soon rusts tools etc I even used it as a corrosive on purpose once. Made a friend some mild steel square tube desk frames and he wanted them to look "distressed", so the bare metal got a wipe-down with FeCl solution. After a few days they were hosed down and lacquered. Didn't look too bad actually, very artsy fartsy. Went well with his brick studio

2009\01\23@082237 by solarwind

On Fri, Jan 23, 2009 at 8:01 AM, William Chops Westfield <RemoveMEwestfwTakeThisOuTmac.com> wrote: > Me either, and I find the chemistry a bit questionable. But the > "everything metal in the workshop starts to rust" effect seems to be > pretty real. (Even the "stainless steel"!) I've always assumed that > it's due to microscopic droplets of etchant solution made airborne by > the bubbler-style agitation. (Hmm. Still a good reason for adequate > ventilation!) Don't want that in your lungs... > BillW > -- solarwind

2009\01\23@084558 by Carl Denk

Granted , I'm doing a little assuming, and having only a little college chemistry. The facts as I know them: 1: The reactions I noted are the major cause of reinforced concrete bridge deck failures in the northern climates where salt NACL is the common deicer. The common item is the chlorine, iron, and the freeing, recombining of the chlorine. 2: Most of the etching chemicals include Chlorine, and I have smelled the gas slightly while etching. Don't know the reactions happening to cause that, or remember what brand or type chemicals, except that chlorine was one of the elements. 3: Within days of etching, this rust appeared on all exposed steel, and some that was in loose boxes. No other chemicals had been used in the area for some time before. This had not happened before in 30 years, and hasn't happened the roughly 2 years after. I think someone can find issue, but the bottom line is, etching does use chemicals that are hazardous, deserve respect, there may be some unintended consequences, and best to be conservative. :) Jinx wrote: {Quote hidden}>> the etching process generally liberates chlorine gas > > I can honestly say I've never smelled chlorine whilst etching. My > guess would be that chlorine ions that don't bond with the copper > will go into solution > > And just checking that > > http://en.wikipedia.org/wiki/Ferric_chloride > > FeCl3 + Cu ? FeCl2 + CuCl > FeCl3 + CuCl ? FeCl2 + CuCl2 > > The brown sludge left over would be the mix of iron and copper > chlorides. ISTR that electrolysis could recover the copper and > convert some of the Fe(II) chloride back to Fe(III) chloride > > > > >

2009\01\23@090236 by solarwind

On Fri, Jan 23, 2009 at 8:45 AM, Carl Denk <cdenkEraseME.....alltel.net> wrote: > Granted , I'm doing a little assuming, and having only a little college > chemistry. The facts as I know them: > 1: The reactions I noted are the major cause of reinforced concrete > bridge deck failures in the northern climates where salt NACL is the > common deicer. The common item is the chlorine, iron, and the freeing, > recombining of the chlorine. > 2: Most of the etching chemicals include Chlorine, and I have smelled > the gas slightly while etching. Don't know the reactions happening to > cause that, or remember what brand or type chemicals, except that > chlorine was one of the elements. > 3: Within days of etching, this rust appeared on all exposed steel, and > some that was in loose boxes. No other chemicals had been used in the > area for some time before. This had not happened before in 30 years, and > hasn't happened the roughly 2 years after. > > I think someone can find issue, but the bottom line is, etching does use > chemicals that are hazardous, deserve respect, there may be some > unintended consequences, and best to be conservative. :) Ok, I'll make an agitation tank and do this outside in my back yard -- solarwind

2009\01\23@092542 by Carl Denk

No agitation or bubbler, other than a gentle rocking of the flat pan container back and forth. All done at room temps, say 70F. :) William "Chops" Westfield wrote: {Quote hidden}> On Jan 23, 2009, at 5:21 AM, Jinx wrote: > >>> the etching process generally liberates chlorine gas >> I can honestly say I've never smelled chlorine whilst etching > > Me either, and I find the chemistry a bit questionable. But the > "everything metal in the workshop starts to rust" effect seems to be > pretty real. (Even the "stainless steel"!) I've always assumed that > it's due to microscopic droplets of etchant solution made airborne by > the bubbler-style agitation. (Hmm. Still a good reason for adequate > ventilation!) > > BillW >

2009\01\23@094402 by solarwind

On Fri, Jan 23, 2009 at 9:25 AM, Carl Denk <EraseMEcdenkalltel.net> wrote: > No agitation or bubbler, other than a gentle rocking of the flat pan > container back and forth. All done at room temps, say 70F. :) But will a heated bubble tank speed up etching and make more sharp lines and allow for .4 mm pitch TQFP chips? -- solarwind

2009\01\23@094526 by solarwind

On Fri, Jan 23, 2009 at 9:44 AM, solarwind <RemoveMEx.solarwind.xEraseMEEraseMEgmail.com> wrote: > On Fri, Jan 23, 2009 at 9:25 AM, Carl Denk <RemoveMEcdenkspam_OUTKILLspamalltel.net> wrote: >> No agitation or bubbler, other than a gentle rocking of the flat pan >> container back and forth. All done at room temps, say 70F. :) > > But will a heated bubble tank speed up etching and make more sharp > lines and allow for .4 mm pitch TQFP chips? > > -- > solarwind Like the PIC32... -- solarwind

2009\01\23@104506 by Joseph Bento

On Jan 22, 2009, at 9:30 PM, Bob Blick wrote: > solarwind wrote: >> I can, >> however, get the chemicals and agitation tank for making my own PCBs > > Agitation tank? Why not just jiggle the Tupperware by hand while you > read or surf the net? > I've done several boards in a Tupperware container. An inexpensive aquarium heater and bubbler will dramatically speed up the etching process, and it's far cheaper than an agitation tank. Joe

2009\01\23@105314 by William \Chops\ Westfield

On Jan 23, 2009, at 6:44 AM, solarwind wrote: > But will a heated bubble tank speed up etching and make more sharp > lines and allow for .4 mm pitch TQFP chips? The etching will likely not be your limiting factor WRT pitch. Resist application is the tough part... BillW

2009\01\23@110033 by William \Chops\ Westfield

On Jan 22, 2009, at 10:49 PM, solarwind wrote: > but I've seen my teacher's end result on a home brew double sided > toner transfer PCB. It was pretty complex and came out very well Ah. You have a local experienced mentor! That should help a lot (and it explains this 'cheap access to expensive stuff' tone I've been hearing.) I was assuming (and I suspect so were others) that you'd be starting from scratch on your own... The worst part of homebrew double-sided boards, IMO, is the lack of plated through holes. Having to add wires and solder your vias isn't TOO bad (although it can prevent you from putting vias UNDER SMT parts, I think), but the places where the PCB assumes that the mounting hold for a TH component will carry a signal from one side of the board to the other are AWFUL; they now need to be soldered on both sides of the board, and that's just not possible with some components! You can design the PCB to correct for this (extra vias!), but it's not 'nice.' BillW

2009\01\23@110341 by Alan B. Pearce

>IMHO you're severely underestimating what can >be done with homebrew double sided. I don't believe anyone is under-estimating it. There used to be products out in the marketplace that used double sided PCBs without plated through holes. The connections that needed to be transferred from one side to the other were done by either the component legs or short tinned copper wire links that were hand assembled into the PCB and soldered both sides. But they weren't without problems ...

2009\01\23@163524 by Jinx

> 1: The reactions I noted are the major cause of reinforced > concrete bridge deck failures in the northern climates where > salt NACL is the common deicer. The common item is the > chlorine, iron, and the freeing, recombining of the chlorine Hi Carl, What you describe is not quite the same type of reaction. The sodium chloride dissociates to Na+ and Cl- which facilitates electrochemical oxidation (rusting) in the presence of water and oxygen Have a quick squiz at the short 'Iron corrosion' section http://en.wikipedia.org/wiki/Electrochemical Etching is a redox reaction, also electrochemical but water ions aren't involved, IOW, in this instance, the two metals exchange possession of the chloride ion Another redox reaction is thermite, where iron oxide is mixed with aluminium and ignited. The aluminium 'steals' the oxygen from the iron. The iron oxide has been reduced, the aluminium has been oxidised => redox. You might think of etching as aqueous thermite. Or you might not Do you recall the electrochemical series ? Generally a list of positive ions ranked in order of their ability to steal negative ions (donate electrons) from positive ions ranked lower on the list In this table you'll see that copper has a greater affinity for -ve ions than iron >http://en.wikipedia.org/wiki/Electronegativities_of_the_elements_(data_page)< The common practical experiment to demonstrate this is throwing alkali metals into water, the reaction getting more violent as you move down the periodic table (eg Mythbusters MacGyver Special) http://en.wikipedia.org/wiki/Electronegativity#Periodic_trends > 2: .......and I have smelled the gas slightly while etching I can only suggest contamination. With pure FeCl3 and clean copper there shouldn't be any significant chlorine release

2009\01\23@165409 by Jinx

> No agitation or bubbler, other than a gentle rocking of the flat pan > container back and forth. All done at room temps, say 70F. :) Raising the temperature even a little will speed things up considerably. The recommended maximum is ~ 55-60C. I haven't found out yet whether that's because the FeCl3 starts breaking down (if so, possibly the cause of your chlorine smell, but 60C seems a bit low for that) or whether the Fe/Cu/Cl interaction changes at an excessive temperature, causing the etching to be slower

2009\01\23@171636 by KPL

> > IMHO you're severely underestimating what can be done with homebrew > double sided. I don't care how much experience you have. I've seen > "experienced" people make some stupid mistakes consistently throughout > their career. Remember that thread about the EE who taught people to > cold solder joints? Ya. I have no experience doing it but I've seen my > teacher's end result on a home brew double sided toner transfer PCB. > It was pretty complex and came out very well, way more than what I had > expected. I was impressed. > Solarwind, there is a mailing list called Homebrew_PCBs on yahoogroups, they have huge collective knowledge on this subject, it may be worth to join that group and check their files area at least. -- KPL

2009\01\23@175201 by sergio masci

On Sat, 24 Jan 2009, Jinx wrote: > > No agitation or bubbler, other than a gentle rocking of the flat pan > > container back and forth. All done at room temps, say 70F. :) > > Raising the temperature even a little will speed things up considerably. > The recommended maximum is ~ 55-60C. I haven't found out yet > whether that's because the FeCl3 starts breaking down (if so, possibly > the cause of your chlorine smell, but 60C seems a bit low for that) or > whether the Fe/Cu/Cl interaction changes at an excessive temperature, > causing the etching to be slower I thought the problem with HOT etchent was that it damages the photoresist? Surely the ABSOLUTE maximum is 50C. Regards Sergio Masci

2009\01\23@175725 by solarwind

On Fri, Jan 23, 2009 at 11:00 AM, William Chops Westfield <RemoveMEwestfwTakeThisOuTspammac.com> wrote: > > On Jan 22, 2009, at 10:49 PM, solarwind wrote: > >> but I've seen my teacher's end result on a home brew double sided >> toner transfer PCB. It was pretty complex and came out very well > > Ah. You have a local experienced mentor! That should help a lot (and > it explains this 'cheap access to expensive stuff' tone I've been > hearing.) I was assuming (and I suspect so were others) that you'd be > starting from scratch on your own... It's a "former" teacher (they don't like the term "old"). I don't have access to him, just see him ocasionally around the school. He used to work there but he retired and only comes in as a supply when the main teacher gets sick or something. I am starting from scratch. I have no "mentors". {Quote hidden}> The worst part of homebrew double-sided boards, IMO, is the lack of > plated through holes. Having to add wires and solder your vias isn't > TOO bad (although it can prevent you from putting vias UNDER SMT > parts, I think), but the places where the PCB assumes that the > mounting hold for a TH component will carry a signal from one side of > the board to the other are AWFUL; they now need to be soldered on both > sides of the board, and that's just not possible with some > components! You can design the PCB to correct for this (extra vias!), > but it's not 'nice.' > > BillW -- solarwind

2009\01\23@175845 by solarwind

On Fri, Jan 23, 2009 at 5:16 PM, KPL <EraseMEkpl.listesspamspamBeGonegmail.com> wrote: > Solarwind, there is a mailing list called Homebrew_PCBs on > yahoogroups, they have huge collective knowledge on this subject, it > may be worth to join that group and check their files area at least. > > -- > KPL > -- Thanks, I'll check it out. -- solarwind

2009\01\23@175858 by solarwind

On Fri, Jan 23, 2009 at 8:32 PM, sergio masci <RemoveMEsmplxKILLspamallotrope.net> wrote: > I thought the problem with HOT etchent was that it damages the > photoresist? Surely the ABSOLUTE maximum is 50C. > > Regards > Sergio Masci I heard somewhere that one should heat to 100 degrees C. -- solarwind

2009\01\23@181228 by sergio masci

On Sat, 24 Jan 2009, Jinx wrote: > In this table you'll see that copper has a greater affinity for -ve ions > than iron I hate to correct you but copper is less reactive than iron. Iron has a greater tendency to lose an electron than copper does. If you look at it like this copper should be unaffected by iron chloride. This does tend to confuse people. However what you should be looking at is the tendency for iron2+ to go to iron3+ and copper0+ to go to copper1+ then you will see that copper0+ goes to copper1+ plus 1 electron and iron3+ plus 1 electron (from the copper above) goes to iron2+ It all comes down to the amount of energy required to remove a electron from an atom or ion verses the amount of energy liberated by adding an electron to another atom or ion. Regards Sergio Masci

2009\01\23@181728 by sergio masci

On Fri, 23 Jan 2009, solarwind wrote: > On Fri, Jan 23, 2009 at 8:32 PM, sergio masci <smplxSTOPspamspam_OUTallotrope.net> wrote: > > I thought the problem with HOT etchent was that it damages the > > photoresist? Surely the ABSOLUTE maximum is 50C. > > > > Regards > > Sergio Masci > > I heard somewhere that one should heat to 100 degrees C. I'm pretty sure this is wrong. I've been using ammonium persulphate at 45C which is the recommended upper limit. I have read that Iron Chloride is faster and needs a lower temp. Regards Sergio Masci

2009\01\23@190809 by Jinx

> However what you should be looking at is the tendency for > iron2+ to go to iron3+ and copper0+ to go to copper1+ Yes, that is the way to look at it, etching of copper by FeCl3 is a two-stage reaction

2009\01\23@194224 by Jinx

> I thought the problem with HOT etchant was that it damages the > photoresist? Don't know about that. What I generally use now is a Sharpie and I'd be guessing what's laid down would be carbon in quite a thin film, probably much like the toner method. Never seen a problem with it lifting or deteriorating. In fact it's possible to have the smallest whisker bridges or fine detail in the resist that will get through the etching undamaged > Surely the ABSOLUTE maximum is 50C The water-jacket method I use gets the etchant to about 60C, give or take, depends on the start temperature of the etchant Just to satisfy my own curiousity I'd like to find out why a limit of 55-60 is often mentioned And don't call me Shirley

2009\01\23@202115 by Peter

FeCl3 etching is always done at over 35 degrees C, else it takes too long and may cause pitting or other artifacts. The exact parameters depend on the required speed and on what the resist can take. Industrial resist is baked after solvent drying and will resist bath temperatures of over 70 degrees C (some resist can take over 100 degrees C). FeCl3 is a mordant for Cu and it will etch vertically (along the crystal grain) first, making pits. This is useful for litography and not useful for PCB etching. The etch direction can be controlled with additives (proprietary) and temperature. Higher temperature makes the etch more isotropic (smoother). See pg 32 - 37 here: dspace.lib.cranfield.ac.uk/bitstream/1826/1846/1/ Blondeau,%20Sebastien%20MSc.pdf (paste on 1 line) Peter

2009\01\23@202324 by sergio masci

On Sat, 24 Jan 2009, Jinx wrote: > > Surely the ABSOLUTE maximum is 50C > > The water-jacket method I use gets the etchant to about 60C, give > or take, depends on the start temperature of the etchant > > Just to satisfy my own curiousity I'd like to find out why a limit of > 55-60 is often mentioned > > And don't call me Shirley Roger Roger.

2009\01\23@211241 by Jinx

> dspace.lib.cranfield.ac.uk/bitstream/1826/1846/1/Blondeau,%20Sebastien%2 0MSc.pdf Interesting, thanks > > And don't call me Shirley > > Roger Roger "Huh ?" ;-) http://www.imdb.com/title/tt0080339/quotes

2009\01\24@185952 by bob.axtell

Hi Solarwind, I think trying to do this stuff is a great waste of time. Just layout the PCB & send it to AP Circuits in Canada or one of the myriad prototype houses. For the $75 you might save "rolling yer own" there is a LOT of grief attached. Are you married? Fooling around with Ferric Chloride will get you locked out of the house in a New York Minute. --Bob A On 1/22/09, solarwind <spamBeGonex.solarwind.xSTOPspamEraseMEgmail.com> wrote: {Quote hidden}> This dude gives a nice, simple guide to etching PCBs - > http://more.random.stuff.googlepages.com/howtomakepcbs > > Looks nice and simple and the results are perfect. > > However, the guys at systm http://revision3.com/systm/etching/ give a > lot of safety tips and make it sound like a very risky job. > > What do you guys think? > > -- > solarwind > -

2009\01\24@201628 by solarwind

On Sat, Jan 24, 2009 at 6:59 PM, <KILLspambob.axtellspamBeGonegmail.com> wrote: > Hi Solarwind, > > I think trying to do this stuff is a great waste of time. Just layout > the PCB & send it to AP Circuits in Canada or one of the myriad > prototype houses. For the $75 you might save "rolling yer own" > there is a LOT of grief attached. > > Are you married? Fooling around with Ferric Chloride will get > you locked out of the house in a New York Minute. > > --Bob A No, I'm not married. I want to, but unfortunately marriage can only be with one other person. I have too many girlfriends. -- solarwind

2009\01\24@202023 by sergio masci

On Fri, 23 Jan 2009, apptech wrote: {Quote hidden}> > > I can probably even make a system to sound an alert after the etching > > time has completed. > > The prior :-) noted - but, most home etching of PCBs of any complexity > benefits greatly from having an eye and brain in the control loop. > > Of course, real men use Pirhana, which etches faster than most people can > think. > > Is it done? > Maybe not. > Is it done? > Just about! > Is it done? > Oh bother!!! > > Use outside. > Ventillate well. > Have paid up insurance. > Fun though. > > > Russell Nah, real men use platimum pentafloride (the stuff that even reacts with noble gasses like xenon) You just threaten to use it on the PCB and it's done :-) Regards Sergio Masci

2009\01\24@204801 by Vitaliy

"Microcontroller discussion list - Public." wrote: > I think trying to do this stuff is a great waste of time. Just layout > the PCB & send it to AP Circuits in Canada or one of the myriad > prototype houses. For the $75 you might save "rolling yer own" > there is a LOT of grief attached. I was able to convince a student whose project we're sponsoring to have his PCB done professionally. Unfortunately, he decided to save some money, and sent his gerbers to a Chinese PCB maker (I forget the name, it was mentioned on this list recently). Murphy intervened, and they won't be able to ship the boards until the end of the Lunar New Year, which would in the best case leave him eight days to assemble, program, and test his project. For time-sensitive stuff, I would definitely go with a US-based manufacturer -- Advanced Circuits lets students buy PCBs for $33 each, and they don't take three week vacations. > Are you married? Fooling around with Ferric Chloride will get > you locked out of the house in a New York Minute. LOL! :) I am lucky to have a very patient and understanding spouse (in many ways, she's a saint). She just asked me if I could do the etching on the balcony, and clean the sink after use. CLR works wonders on the plastic sinks, you just let it sit for 15 minutes or so, and you can wipe the rust off with your finger. Solarwind isn't married, but FeCl3 can surely get him in trouble with his parents. :) Vitaliy

2009\01\24@211542 by Joseph Bento

On Jan 24, 2009, at 6:16 PM, solarwind wrote: > > No, I'm not married. I want to, but unfortunately marriage can only be > with one other person. I have too many girlfriends. Well, just choose one and beat the others off with a stick! :-) Joe

2009\01\24@213748 by solarwind

On Sat, Jan 24, 2009 at 9:15 PM, Joseph Bento <EraseMEjosephEraseMEkirtland.com> wrote: > > On Jan 24, 2009, at 6:16 PM, solarwind wrote: >> >> No, I'm not married. I want to, but unfortunately marriage can only be >> with one other person. I have too many girlfriends. > > > Well, just choose one and beat the others off with a stick! :-) > > > Joe Lol, if I chose one, it would get boring. Besides, the beating I'll be doing wont be with a stick. -- solarwind

2009\01\24@215416 by Sean Breheny

On Sat, Jan 24, 2009 at 8:16 PM, solarwind <@spam@x.solarwind.x@spam@spam_OUTgmail.com> wrote: > No, I'm not married. I want to, but unfortunately marriage can only be > with one other person. I have too many girlfriends. Sounds like a nice problem to have!!! > > -- > solarwind > -

2009\01\25@080706 by apptech

> For > time-sensitive stuff, I would definitely go with a US-based > manufacturer -- > Advanced Circuits lets students buy PCBs for $33 each, and they don't take > three week vacations. Chinese new year is usually 10 days. And it's by far the largest holiday taken. Outside that period you are liable to et them to work 8 days a week, sometimes 9. That said, it depends how westernised the firm has got. Some work Sundays without a qualm while others actually do do 40 hour weeks. Then others I've seen do 7 day 70 hour weeks ... . FWIW: I'll be back in China just after the new year celebrations end. Russell

2009\01\25@123749 by Vitaliy

"apptech" wrote: > Chinese new year is usually 10 days. > And it's by far the largest holiday taken. You've got to figure in the travel time, too. > Outside that period you are > liable to et them to work 8 days a week, sometimes 9. I work this kind of schedule myself. :) > That said, it depends how westernised the firm has got. Some work Sundays > without a qualm while others actually do do 40 hour weeks. Then others > I've > seen do 7 day 70 hour weeks ... . That *is* pretty crazy. > FWIW: I'll be back in China just after the new year celebrations end. I hope there will be more pictures? Vitaliy

2009\01\25@135528 by Richard Prosser

2009/1/26 apptech <spamBeGoneapptechKILLspamparadise.net.nz>: {Quote hidden}>> For >> time-sensitive stuff, I would definitely go with a US-based >> manufacturer -- >> Advanced Circuits lets students buy PCBs for $33 each, and they don't take >> three week vacations. > > Chinese new year is usually 10 days. > And it's by far the largest holiday taken. Outside that period you are > liable to et them to work 8 days a week, sometimes 9. > > That said, it depends how westernised the firm has got. Some work Sundays > without a qualm while others actually do do 40 hour weeks. Then others I've > seen do 7 day 70 hour weeks ... . > > FWIW: I'll be back in China just after the new year celebrations end. > > > > Russell > > Russel So will I - I'm in Shenzhen from the 5th to about the 18th, how about you? Richard

2009\01\25@212048 by Peter

William "Chops" Westfield <westfw <at> mac.com> writes: > > I can honestly say I've never smelled chlorine whilst etching As you may have read in the pdf document linked by me before, FeCl3 etches by releasing Cl ions into the solution. It is very likely that the presence of some impurites can cause HCl and other toxic chemicals to be released into the air bubbles that percolate through the solution. The FeCl3 bath has a peculiar characteristic smell, but that is not the smell of chlorine. Adding certain chemicals to the bath while trying to neutralize it can produce really bad fumes, however. Peter

2009\01\25@213250 by Forrest W Christian

Back when I was etching boards myself, I was a big fan of ammonium persulphate. Much less nasty than Ferric Chloride. -forrest Peter wrote: {Quote hidden}> William "Chops" Westfield <westfw <at> mac.com> writes: > >>> I can honestly say I've never smelled chlorine whilst etching >>> > > As you may have read in the pdf document linked by me before, FeCl3 etches by > releasing Cl ions into the solution. It is very likely that the presence of some > impurites can cause HCl and other toxic chemicals to be released into the air > bubbles that percolate through the solution. The FeCl3 bath has a peculiar > characteristic smell, but that is not the smell of chlorine. Adding certain > chemicals to the bath while trying to neutralize it can produce really bad > fumes, however. > > Peter > > >

2009\01\25@214901 by solarwind

On Sun, Jan 25, 2009 at 9:30 PM, Forrest W Christian <.....forrestcspam_OUTimach.com> wrote: > Back when I was etching boards myself, I was a big fan of ammonium > persulphate. Much less nasty than Ferric Chloride. > > -forrest I'll give that a try - thanks. -- solarwind

2009\01\26@032924 by Jinx

> persulphate. Much less nasty than Ferric Chloride. I agree but add that in any situation there is only potential for nastiness. What ? Well, FeCl3 is only nasty if you allow it to do something you shouldn'ta Treat it with care and pay attention. Wear a smock and eye protection, don't drink it, don't splash it around or use on a surface that you don't worry about messing up and dispose of it conscientiously Compared with most other life hazards, especially those around the workshop, it's not a biggie

2009\01\26@120915 by Isaac Marino Bavaresco

Jinx escreveu: >> persulphate. Much less nasty than Ferric Chloride. >> > > I agree but add that in any situation there is only potential for > nastiness. What ? Well, FeCl3 is only nasty if you allow it to do > something you shouldn'ta > > Treat it with care and pay attention. Wear a smock and eye > protection, don't drink it, don't splash it around or use on a > surface that you don't worry about messing up and dispose > of it conscientiously > > Compared with most other life hazards, especially those around > the workshop, it's not a biggie > I started using FeCl3 when I was 12 years old. Now I am 38 and don't think it affected may health in any way. In the early years, I used to stain my hands and clothes with it and breathing its vapors. The stains lasted weeks in the skin and forever in the clothes. Now I use the services of a local shop that makes photolithographic films and cliché (metallic stamp) for the printing industries. They provide a semi-professional PCB service (industry quality etched board without solder mask, silk-screen or drilling). I send them the Gerber files by e-mail and after +- 4 hours the board is ready. Usually each board below 5"x5" costs around US$7.00 (bigger boards cost a little more). I probably will never etch my own prototype boards again. I think other shops in this business that etch metal cliché may do PCBs either. Just go there and ask if they are interested in making prototype PCBs. Best regards, Isaac __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\26@141938 by solarwind

On Mon, Jan 26, 2009 at 11:41 AM, Isaac Marino Bavaresco <TakeThisOuTisaacbavaresco.....TakeThisOuTyahoo.com.br> wrote: > Now I use the services of a local shop that makes photolithographic > films and cliché (metallic stamp) for the printing industries. They > provide a semi-professional PCB service (industry quality etched board > without solder mask, silk-screen or drilling). I send them the Gerber > files by e-mail and after +- 4 hours the board is ready. > > Usually each board below 5"x5" costs around US$7.00 (bigger boards cost > a little more). > > I probably will never etch my own prototype boards again. > > I think other shops in this business that etch metal cliché may do PCBs > either. Just go there and ask if they are interested in making prototype > PCBs. > > Best regards, > > Isaac That certainly sounds interesting. So basically you give them a blank copper clad board and they do a single sided PCB for you? -- solarwind

2009\01\26@144514 by Isaac Marino Bavaresco

solarwind escreveu: {Quote hidden}> On Mon, Jan 26, 2009 at 11:41 AM, Isaac Marino Bavaresco > <TakeThisOuTisaacbavarescoKILLspamspamyahoo.com.br> wrote: > >> Now I use the services of a local shop that makes photolithographic >> films and cliché (metallic stamp) for the printing industries. They >> provide a semi-professional PCB service (industry quality etched board >> without solder mask, silk-screen or drilling). I send them the Gerber >> files by e-mail and after +- 4 hours the board is ready. >> >> Usually each board below 5"x5" costs around US$7.00 (bigger boards cost >> a little more). >> >> I probably will never etch my own prototype boards again. >> >> I think other shops in this business that etch metal cliché may do PCBs >> either. Just go there and ask if they are interested in making prototype >> PCBs. >> >> Best regards, >> >> Isaac >> > > That certainly sounds interesting. So basically you give them a blank > copper clad board and they do a single sided PCB for you? > They have already some blank PCB panels in stock. And they do double-sided also, I just need to drill it myself. __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\26@144538 by Isaac Marino Bavaresco

solarwind escreveu: {Quote hidden}> On Mon, Jan 26, 2009 at 11:41 AM, Isaac Marino Bavaresco > <.....isaacbavarescoRemoveMEyahoo.com.br> wrote: > >> Now I use the services of a local shop that makes photolithographic >> films and cliché (metallic stamp) for the printing industries. They >> provide a semi-professional PCB service (industry quality etched board >> without solder mask, silk-screen or drilling). I send them the Gerber >> files by e-mail and after +- 4 hours the board is ready. >> >> Usually each board below 5"x5" costs around US$7.00 (bigger boards cost >> a little more). >> >> I probably will never etch my own prototype boards again. >> >> I think other shops in this business that etch metal cliché may do PCBs >> either. Just go there and ask if they are interested in making prototype >> PCBs. >> >> Best regards, >> >> Isaac >> > > That certainly sounds interesting. So basically you give them a blank > copper clad board and they do a single sided PCB for you? > They have already some blank PCB panels in stock. And they do double-sided also, I just need to drill it myself. __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\26@153647 by solarwind

On Mon, Jan 26, 2009 at 2:44 PM, Isaac Marino Bavaresco <RemoveMEisaacbavarescospamBeGoneyahoo.com.br> wrote: > They have already some blank PCB panels in stock. > And they do double-sided also, I just need to drill it myself. What method do they use to produce it? -- solarwind

2009\01\26@174510 by Jinx

> Now I use the services of a local shop that makes photolithographic > films and cliché (metallic stamp) for the printing industries Isaac, don't get me wrong. For quantity and quality I always use the professionals, but etch my own one-offs, prototypes, test boards, and those funny little boards you sometimes need (like a little SMT to DIP).\ I go through a lot of proto boards for various ideas and products at different stages and if I couldn't do my own it would be very inconveneient. Breadboards are OK too but they have their limits Cost is not a significant factor, but in the time it takes to draw it all up with a CAD package and get it to the board house I can have a hand-made one ready to use. And that's not forgetting the several days waiting for the board house. When you need a board, any board, to work with and you need it, to quote Steve Martin, "right %#$^ing now", there's nothing wrong with a home-brew

2009\01\26@180521 by solarwind

On Mon, Jan 26, 2009 at 6:43 PM, Jinx <spamBeGonejoecolquitt@spam@spam_OUTclear.net.nz> wrote: > Isaac, don't get me wrong. For quantity and quality I always use the > professionals, but etch my own one-offs, prototypes, test boards, and > those funny little boards you sometimes need (like a little SMT to DIP).\ > > I go through a lot of proto boards for various ideas and products at > different stages and if I couldn't do my own it would be very inconveneient. > Breadboards are OK too but they have their limits > > Cost is not a significant factor, but in the time it takes to draw it all up > with > a CAD package and get it to the board house I can have a hand-made one > ready to use. And that's not forgetting the several days waiting for the board > house. When you need a board, any board, to work with and you need it, > to quote Steve Martin, "right %#$^ing now", there's nothing wrong with a > home-brew > > Well put. Thank you. -- solarwind

2009\01\26@194059 by Isaac Marino Bavaresco

Jinx escreveu: >> Now I use the services of a local shop that makes photolithographic >> films and cliché (metallic stamp) for the printing industries >> > > Isaac, don't get me wrong. For quantity and quality I always use the > professionals, but etch my own one-offs, prototypes, test boards, and > those funny little boards you sometimes need (like a little SMT to DIP).\ > For production batches, of course I use the service of professional shops, with components silk-screen, solder mask, plated holes (for multi-layer boards) and HAL Sn-Pb. > I go through a lot of proto boards for various ideas and products at > different stages and if I couldn't do my own it would be very inconveneient. > Breadboards are OK too but they have their limits > I usually draw a board and make a prototype, then adjust the circuit by cutting/bridging traces and changing component values. After everything is OK I rework the first design and make the final boards. If I´m not 100% confident I make one more prototype. It´s hard to breadboard or proto-board circuits with several 100-pin 0.5mm pitch ICs. I don´t like adapters also, and they are expensive too. And for some circuits proto-boards may introduce undesirable effects. I use proto-boards only to pre-test sub-circuits that I think may be hard to get right. > Cost is not a significant factor, but in the time it takes to draw it all up > with > a CAD package and get it to the board house I can have a hand-made one > ready to use. And that's not forgetting the several days waiting for the board > The shop I use for prototypes is here in my city and they make my boards the same day. I send them the files by e-mail in the morning and receive the boards by courier in the afternoon. > house. When you need a board, any board, to work with and you need it, > to quote Steve Martin, "right %#$^ing now", there's nothing wrong with a > home-brew > Of course it´s OK to etch your boards, but I found their services so convenient that I´m not compelled to do it myself anymore. Besides, I can´t reach their 8000+ DPI quality. Regards, Isaac __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\26@195351 by Isaac Marino Bavaresco

solarwind escreveu: > On Mon, Jan 26, 2009 at 2:44 PM, Isaac Marino Bavaresco > <TakeThisOuTisaacbavarescospamyahoo.com.br> wrote: > >> They have already some blank PCB panels in stock. >> And they do double-sided also, I just need to drill it myself. >> > > What method do they use to produce it? > They make the film in a laser photoplotter, then sensitize (cover) the boards with photoresist and expose the board to a special light, with the film on top of it. Then they use some nasty chemicals to remove the un-exposed resist and etch the exposed copper with FeCl3. To finish, the hardened resist is removed with caustic soda. The drilling I do myself. Best regards, Isaac __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\26@202809 by solarwind

On Mon, Jan 26, 2009 at 7:53 PM, Isaac Marino Bavaresco <isaacbavarescoEraseMEyahoo.com.br> wrote: > They make the film in a laser photoplotter, then sensitize (cover) the > boards with photoresist and expose the board to a special light, with > the film on top of it. > Then they use some nasty chemicals to remove the un-exposed resist and > etch the exposed copper with FeCl3. > > To finish, the hardened resist is removed with caustic soda. > > The drilling I do myself. > > > Best regards, > > Isaac Do they do through-hole plating? Also, if I were to look for one of these places in my area, how would I find it? -- solarwind

2009\01\26@205418 by Jinx

> It´s hard to breadboard or proto-board circuits with several 100-pin > 0.5mm pitch ICs Agree with that completely, but it's hard to ignore that little voice saying "Yeah, go on, you can do it". 1mm I'd have a look at, not 0.5mm. Tried and failed. Still, that's how you find out I think I do what most people would do. If it's a job you can do reasonably competently or better, then DIY. eg a lot of jobs I've done (to a good standard IMVHO) around the house. I wouldn't even think of getting a builder or a painter in. I wouldn't get an IT wiz to lay LAN cables either. There are times when you need professionals, times when you don't, and it's not always so simple as having or saving $$$ or being/not being capable of doing it yourself

2009\01\26@205958 by Isaac Marino Bavaresco

solarwind escreveu: {Quote hidden}> On Mon, Jan 26, 2009 at 7:53 PM, Isaac Marino Bavaresco > <RemoveMEisaacbavarescoEraseMEspam_OUTyahoo.com.br> wrote: > >> They make the film in a laser photoplotter, then sensitize (cover) the >> boards with photoresist and expose the board to a special light, with >> the film on top of it. >> Then they use some nasty chemicals to remove the un-exposed resist and >> etch the exposed copper with FeCl3. >> >> To finish, the hardened resist is removed with caustic soda. >> >> The drilling I do myself. >> >> >> Best regards, >> >> Isaac >> > > Do they do through-hole plating? Also, if I were to look for one of > these places in my area, how would I find it? > No, they don´t do through-hole plating. I´m in Brazil and speak Portuguese, but the English equivalent would be "photo-engraver". Try these keywords also: photolith film, flexography, photoplotter, etch. __________________________________________________ Faça ligações para outros computadores com o novo Yahoo! Messenger http://br.beta.messenger.yahoo.com/

2009\01\27@003147 by Peter

Forrest W Christian <forrestc <at> imach.com> writes: > persulphate. Much less nasty than Ferric Chloride. FeCl3 is used in industrial quantities in water treatment plants. It is not particularly nasty as a chemical (it is a close relative of common rust, so to speak). Don't drink it, don't get it into your eyes and don't worry about it. The nasty part is the copper salts that appear in used etching baths. That is toxic (the copper), not the FeCl3. Peter

2009\01\27@124638 by Peter

solarwind <x.solarwind.x <at> gmail.com> writes: > I want to build a simple tank with a heater because I want to make I used a tupperware/rubbermaid style hinged lid, tall, rectangular container to keep 1 liter of FeCl3 solution and made my boards in it for more than 2 years. The closed lid keeps air out and the solution viable for longer. Air will kill the solution faster than the boards you make. FeCl3 comes in pebble like rust colored lumps. You put them in the container and cover with water from the hot water kettle, and stir until dissolved. That's it mostly. If you want to be accurate get a liquid density gauge (the kind used for tomato juice is right) and adjust the density with water until it is just right (32 degrees Baume at 50 deg. C). Let it sit for a few hours before first use. My high tech way to do it X years ago was: 1. put a large pebble in the FeCl3 container so it won't float (see below) 2. put an old phone book on the floor (thermal insulation and spill soak-up) 3. put a 2-3l tupperware container on the phone book 4. pour +1l of boiling water from the kettle into the large container 5. put the weighted (pebble) etchant container in the large container 6. wait about 5-10 minutes for the etchant to heat up a little 7. put the board in the etchant container and etch for 20-25 minutes with occasional rocking. The board was hung by fishing line monofilament from a pencil or wood stick (brush handle) that sat on top the etchant container. Periodically remove the board to inspect it against a strong light for etching completion and problems. Drill a hole in the edge of the board to thread the monofilament through. The board should not touch the container while hanging in the etchant. My high tech way I did not implement (never needed it): 1. use a flat container for the etchant (tray like) 2. obtain a cardboard box that is slightly smaller than it 3. cut the lid off the cardboard box, line it with aluminum foil and mount a 40-75 Watt light fixture and bulb in it (wattage tbd) 4. duct tape the cardboard box to the bottom of the tray (around it) using heavy duty tape. The other sode of the box can be opened to change bulbs. 5. fill the bath with H2O, turn on the light, and use a liquid thermometer to get the right wattage that keeps the H2O at 45-55 deg. C indefinitely. 6. replace the H2O with FeCl3 solution and etch boards in style, while the light shining through the bottom of the plastic container allows etching inspection without removing the board, besides keeping the solution at the right temperature. 7. optionally add a $2 'cocktail stirrer' (with plastic stirrer paddle) to be clamped to the tray and agitate the solution. (you first saw it here) Peter PS: FeCl3 tends to corrode everything so it is a no shipping item. Obtain it locally from a chemical supply. It only costs a few dollars per pound/kg. PS2: Wrt toxicity and MSDS - compare the msds sheets of NaCl and FeCl3 :) :) (hint: salt is to be kept 'locked up' and is 'mutagenic to mammalian somatic cells' - the other ingredient of the solution is dihydorgen monoxyde, also dangerous when ingested in large quantities or inhaled)

2009\01\27@141021 by solarwind

On Tue, Jan 27, 2009 at 12:45 PM, Peter <@spam@plpeter2006RemoveMEEraseMEyahoo.com> wrote: {Quote hidden}> I used a tupperware/rubbermaid style hinged lid, tall, rectangular container to > keep 1 liter of FeCl3 solution and made my boards in it for more than 2 years. > The closed lid keeps air out and the solution viable for longer. Air will kill > the solution faster than the boards you make. > > FeCl3 comes in pebble like rust colored lumps. You put them in the container > and cover with water from the hot water kettle, and stir until dissolved. > That's it mostly. If you want to be accurate get a liquid density gauge (the > kind used for tomato juice is right) and adjust the density with water until > it is just right (32 degrees Baume at 50 deg. C). Let it sit for a few hours > before first use. > > My high tech way to do it X years ago was: > > 1. put a large pebble in the FeCl3 container so it won't float (see below) > 2. put an old phone book on the floor (thermal insulation and spill soak-up) > 3. put a 2-3l tupperware container on the phone book > 4. pour +1l of boiling water from the kettle into the large container > 5. put the weighted (pebble) etchant container in the large container > 6. wait about 5-10 minutes for the etchant to heat up a little > 7. put the board in the etchant container and etch for 20-25 minutes with > occasional rocking. The board was hung by fishing line monofilament from a > pencil or wood stick (brush handle) that sat on top the etchant container. > Periodically remove the board to inspect it against a strong light for > etching completion and problems. Drill a hole in the edge of the board to > thread the monofilament through. The board should not touch the container > while hanging in the etchant. > > My high tech way I did not implement (never needed it): > > 1. use a flat container for the etchant (tray like) > 2. obtain a cardboard box that is slightly smaller than it > 3. cut the lid off the cardboard box, line it with aluminum foil and mount a > 40-75 Watt light fixture and bulb in it (wattage tbd) > 4. duct tape the cardboard box to the bottom of the tray (around it) using > heavy duty tape. The other sode of the box can be opened to change bulbs. > 5. fill the bath with H2O, turn on the light, and use a liquid thermometer to > get the right wattage that keeps the H2O at 45-55 deg. C indefinitely. > 6. replace the H2O with FeCl3 solution and etch boards in style, while the > light shining through the bottom of the plastic container allows etching > inspection without removing the board, besides keeping the solution at the > right temperature. > 7. optionally add a $2 'cocktail stirrer' (with plastic stirrer paddle) to be > clamped to the tray and agitate the solution. > > (you first saw it here) > Peter > > PS: FeCl3 tends to corrode everything so it is a no shipping item. Obtain it > locally from a chemical supply. It only costs a few dollars per pound/kg. > > PS2: Wrt toxicity and MSDS - compare the msds sheets of NaCl and FeCl3 :) :) > (hint: salt is to be kept 'locked up' and is 'mutagenic to mammalian somatic > cells' - the other ingredient of the solution is dihydorgen monoxyde, also > dangerous when ingested in large quantities or inhaled) Your high-tech way is genious. Bud do you think an incandescent bulb of 40 - 75 watt will release enough heat to keep the solution at 50 degrees C? -- solarwind

2009\01\27@145332 by olin piclist

solarwind wrote: > Bud do you think an incandescent bulb > of 40 - 75 watt will release enough heat to keep the solution at 50 > degrees C? Incandescent bulb are crappy light generators, but very cheap and effective resistive heaters. 40 to 75 watts of incandescent bulb will get you 39 to 73 watts of heat or so. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000.

2009\01\27@153119 by solarwind

On Tue, Jan 27, 2009 at 2:53 PM, Olin Lathrop <EraseMEolin_piclist@spam@embedinc.com> wrote: > Incandescent bulb are crappy light generators, but very cheap and effective > resistive heaters. 40 to 75 watts of incandescent bulb will get you 39 to > 73 watts of heat or so. Wow. Time to make a light box. Damn ya learn something new every day. I searched and searched on Google but I kept getting the same old fish tank bubble results... I never get anything new or innovative like this. I've also searched for etching PCBs and I didn't hear of the direct inkjet-to-copper clad method till someone mentioned it on this list. -- solarwind

2009\01\27@170651 by Peter

solarwind <x.solarwind.x <at> gmail.com> writes: > > Incandescent bulb are crappy light generators, but very cheap and effective > > resistive heaters. 40 to 75 watts of incandescent bulb will get you 39 to > > 73 watts of heat or so. > > Wow. Time to make a light box. Damn ya learn something new every day. Actually an incandescent light makes for a crappy light box. Use an energy saving 'electronic' lamp for that, and a diffuser (calque drawing paper works in a pinch). As Olin has noticed, the incandescent bulb provides both light and heat, and about as much heat as an aquarium heater provides, which is about the right size for that kind of etching tray job. Peter

2009\01\27@171926 by olin piclist

solarwind wrote: >> Incandescent bulb are crappy light generators, but very cheap and >> effective resistive heaters. 40 to 75 watts of incandescent bulb >> will get you 39 to 73 watts of heat or so. > > Wow. Time to make a light box. It seems you got it backwards. If you want light, incandescent bulbs would be the last choice. I was trying to point out that they are far better heaters than light sources. If I remember right, something like 2.5% efficient light sources, which would make them 97.5% efficient heaters even if all the light escapes. A plain old resistor is a 100% efficient heater, but nowhere near as cheap and available as incandescent bulbs at 10s of watts. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000.

2009\01\27@171937 by solarwind

On Tue, Jan 27, 2009 at 5:06 PM, Peter <@spam@plpeter2006spam_OUT.....yahoo.com> wrote: > Actually an incandescent light makes for a crappy light box. Use an energy > saving 'electronic' lamp for that, and a diffuser (calque drawing paper works in > a pinch). As Olin has noticed, the incandescent bulb provides both light and > heat, and about as much heat as an aquarium heater provides, which is about the > right size for that kind of etching tray job. > > Peter Yeah, that's what I meant. I'll use it for its heat output. -- solarwind

2009\01\27@172455 by solarwind

On Tue, Jan 27, 2009 at 5:19 PM, Olin Lathrop <spamBeGoneolin_piclistEraseMEembedinc.com> wrote: > It seems you got it backwards. If you want light, incandescent bulbs would > be the last choice. I was trying to point out that they are far better > heaters than light sources. If I remember right, something like 2.5% > efficient light sources, which would make them 97.5% efficient heaters even > if all the light escapes. A plain old resistor is a 100% efficient heater, > but nowhere near as cheap and available as incandescent bulbs at 10s of > watts. I got it right, lol, I just used the wrong word. I meant heat box. Heat box. Yes. -- solarwind

2009\01\27@174422 by sergio masci

On Tue, 27 Jan 2009, solarwind wrote: {Quote hidden}> On Tue, Jan 27, 2009 at 5:19 PM, Olin Lathrop <olin_piclistspamBeGoneembedinc.com> wrote: > > It seems you got it backwards. If you want light, incandescent bulbs would > > be the last choice. I was trying to point out that they are far better > > heaters than light sources. If I remember right, something like 2.5% > > efficient light sources, which would make them 97.5% efficient heaters even > > if all the light escapes. A plain old resistor is a 100% efficient heater, > > but nowhere near as cheap and available as incandescent bulbs at 10s of > > watts. > > I got it right, lol, I just used the wrong word. I meant heat box. > Heat box. Yes. > Try again - you mean an oven :-) Regards Sergio Masci

2009\01\27@181300 by Peter

solarwind <x.solarwind.x <at> gmail.com> writes: > Yeah, that's what I meant. I'll use it for its heat output. You use it for both light and heat. The light will shine through the bottom of the plastic tray and through the board being etched and the solution, so you can see when the etching is about done, as well as small misplaced things and dirt in the solution. The light will go through the 1-2 cm deep solution and the board (where there is no copper). Peter

2009\01\27@193639 by Nate Duehr

Wow, I'm kinda surprised this isn't more widely known. I've seen people use incandescent bulb lamps under sinks in houses that were "closed up for winter" as poor-man's anti-pipe-freezing tools, and at least one radio club that was having radio problems with a mountain-top site that had plenty of power, but no built in heating system, use a 100W bulb and some judicious use of cardboard (around the radio, to keep the heat from rising up the cabinet), to keep a crystal on-frequency until repairs could be made the next summer. Drop-lights... they're not just for lighting anymore! (GRIN) Nate {Original Message removed}

2009\01\28@133717 by Alan B. Pearce

>Wow, I'm kinda surprised this isn't more widely known. Me too ... >I've seen people use incandescent bulb lamps under sinks >in houses that were "closed up for winter" as poor-man's >anti-pipe-freezing tools, ... I new of a guy who lived in Fiji, who used a 15W pygmy lamp in the bottom of the cupboard where he stored his photographic equipment, to keep the equipment at a temperature where the humidity was lowered enough to keep fungi from growing on lenses, and generally limit the effects of the humidity on the rest of the gear. This was all around 40 years ago.

2009\01\28@142855 by Bob Axtell

In my young engineer days at Texas Instruments I was sent on a field trip to repair a semi-custom piece of electronic gear in central America (Guatemala). For two weeks I lived in a house near the beach. There was a 75watt incandescent bulb always on in the clothes closet. I was told that if it were turned off or removed, the humidity and the insects would ravage the clothes. It seemed to work for me. The problem took a while to solve. It turned out that critical PCBs in the ailing system had to be sprayed with a plastic spray to prevent moisture from condensing on the PCB surfaces. I used Scotch (3M) polaroid film coating; its all I could find in that village. Fun stuff. --Bob On Wed, Jan 28, 2009 at 11:37 AM, Alan B. Pearce <RemoveMEAlan.B.Pearce@spam@spamBeGonestfc.ac.uk> wrote: {Quote hidden}>>Wow, I'm kinda surprised this isn't more widely known. > > Me too ... > >>I've seen people use incandescent bulb lamps under sinks >>in houses that were "closed up for winter" as poor-man's >>anti-pipe-freezing tools, > ... > > I new of a guy who lived in Fiji, who used a 15W pygmy lamp in the bottom of > the cupboard where he stored his photographic equipment, to keep the > equipment at a temperature where the humidity was lowered enough to keep > fungi from growing on lenses, and generally limit the effects of the > humidity on the rest of the gear. This was all around 40 years ago. > > -

2009\01\28@165437 by William \Chops\ Westfield

>> [incandescent lamps as heaters.] > I'm kinda surprised this isn't more widely known. It *IS* widely known. There must be hundreds of children's toys over the last 50 years that use a light bulb as the heating source for all sorts of oven-like devices, starting with your classic "Easy Bake Oven"... BillW

2009\01\28@174822 by Tamas Rudnai

> No, I'm not married. I want to, but unfortunately marriage can only be > with one other person. I have too many girlfriends. There are some countries where you can have up to 4 wifes if you have enough money. You may need to change location and religion :-) Tamas PS: For me 1 is too many sometimes, especially when I want to work on something late night :-) On Sun, Jan 25, 2009 at 1:16 AM, solarwind <.....x.solarwind.x@spam@EraseMEgmail.com> wrote: {Quote hidden}> On Sat, Jan 24, 2009 at 6:59 PM, <.....bob.axtellRemoveMEgmail.com> wrote: > > Hi Solarwind, > > > > I think trying to do this stuff is a great waste of time. Just layout > > the PCB & send it to AP Circuits in Canada or one of the myriad > > prototype houses. For the $75 you might save "rolling yer own" > > there is a LOT of grief attached. > > > > Are you married? Fooling around with Ferric Chloride will get > > you locked out of the house in a New York Minute. > > > > --Bob A > > No, I'm not married. I want to, but unfortunately marriage can only be > with one other person. I have too many girlfriends. > > -- > solarwind > -

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