Post by thread:[EE:]PCB Making

I have purchased RS Components Aerosol photo resist 198-9651. They suggest that I need to use a there "Universal Developer" 690-849. Is this really needed as it is expensive. I thought the UV light exposure would soften the photo resist enough for etching - but if this is not the case then what does exposing to UV do? I was just going to use the photo resist then etch it. ************************************************* Roy Hopkins :-) Tauranga New Zealand ************************************************* --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.708 / Virus Database: 464 - Release Date: 18/06/2004 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Hopkins wrote: > I have purchased RS Components Aerosol photo resist 198-9651. > > They suggest that I need to use a there "Universal Developer" 690-849. Is > this really needed as it is expensive. > > I thought the UV light exposure would soften the photo resist enough > for etching - but if this is not the case then what does exposing to UV do? > > I was just going to use the photo resist then etch it. > > ************************************************* > Roy Hopkins :-) > > Tauranga > New Zealand > ************************************************* The UV does not soften the photo resist, it hardens the exposed photo resist. You need some sort of developer otherwise the etchant will never get to the copper. -- -- Martin Klingensmith http://infoarchive.net/ http://nnytech.net/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> They suggest that I need to use a there "Universal Developer" > 690-849. Is this really needed as it is expensive. They suggest in one of their etching pdfs (232-3686) that sodium hydroxide can be used instead -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> > > They suggest that I need to use a there "Universal Developer" > > > 690-849. Is this really needed as it is expensive. > > > > They suggest in one of their etching pdfs (232-3686) that sodium > > hydroxide can be used instead Caustic soda / sodium hydroxide / lye is a common developer for some etch resists. It attacks the unexposed resist but works much more slowly on the exposed resist. Google has lots on this. You can buy caustic soda from grocery stores or "chemists". Typically people seem to be using 7 gm/litre (a bit under 1% solution). One of many refs http://www.xs4all.nl/~pquanjer/spectechn/photogravure.htm The exposed developer can often be removed after etching with acetone - or a scouring pad. RM -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

IIRC, in college we used cheap cheap cheap powder detergent. I'm pretty sure that the cheap cheap cheap stuff is mainly just NaOH with some cutting agent; obviously best to steer clear of things with scents and fabric softeners and what-not. This is me dredging data up from a single day's explanation of methods, from over four years ago, so naturally, YMMV. Mike H. {Quote hidden}>I have purchased RS Components Aerosol photo resist 198-9651. > >They suggest that I need to use a there "Universal Developer" 690-849. Is >this really needed as it is expensive. > > I thought the UV light exposure would soften the photo resist enough >for etching - but if this is not the case then what does exposing to UV >do? > >I was just going to use the photo resist then etch it. > >************************************************* >Roy Hopkins :-) > >Tauranga >New Zealand >************************************************* > > > >--- >Outgoing mail is certified Virus Free. >Checked by AVG anti-virus system (http://www.grisoft.com). >Version: 6.0.708 / Virus Database: 464 - Release Date: 18/06/2004 > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. _________________________________________________________________ MSN Toolbar provides one-click access to Hotmail from any Web page FREE download! http://toolbar.msn.click-url.com/go/onm00200413ave/direct/01/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Jun 22, 2004, at 7:07 AM, Mike Hord wrote: > IIRC, in college we used cheap cheap cheap powder detergent. Cheap replacement developers I've heard used include lye (sodium or potassium hydroxide) (rather dangerous and nasty), Washing soda (sodium or potassium carbonate), and sodium metasilicates (which are a common ingredient in harsher detergents.) Some simple tests might be in order. BillW -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

The stuff I used to use had an uncanny resemblance to dishwasher powder. RP On Jun 22, 2004, at 7:07 AM, Mike Hord wrote: > IIRC, in college we used cheap cheap cheap powder detergent. Cheap replacement developers I've heard used include lye (sodium or potassium hydroxide) (rather dangerous and nasty), Washing soda (sodium or potassium carbonate), and sodium metasilicates (which are a common ingredient in harsher detergents.) Some simple tests might be in order. BillW -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> From: Mike Hord[SMTP:spam_OUTgaidinmdTakeThisOuTHOTMAIL.COM] > Sent: Tuesday, June 22, 2004 10:07 AM > To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Subject: Re: [EE:]PCB Making > IIRC, in college we used cheap cheap cheap powder detergent. I'm pretty > sure that the cheap cheap cheap stuff is mainly just NaOH with some > cutting agent; obviously best to steer clear of things with scents and > fabric > softeners and what-not. > This is me dredging data up from a single day's explanation of methods, > from over four years ago, so naturally, YMMV. > Mike H. I remember using TSP or Tri-Sodium Phosphate as a resist developer. John Power -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

some commercial board makers also use sodium hydroxide and hydrogen peroxide as an etchant, for them keeping the right concentration of each is a problem but for small users you could just mix up fresh often. i don't remember what the preferred concentration of each is, but no doubt a quick google would tell. of course disposal is a problem, you need to make the copper come out of solution before you can dump the rest down the drain, but i also seem to remember there are tricks for this as well (simple tricks, like neutralizing the ph etc. and then filtering the copper particles out). Russell McMahon wrote: {Quote hidden}> > > > > They suggest that I need to use a there "Universal Developer" > > > > 690-849. Is this really needed as it is expensive. > > > > > > They suggest in one of their etching pdfs (232-3686) that sodium > > > hydroxide can be used instead > > Caustic soda / sodium hydroxide / lye is a common developer for some etch > resists. It attacks the unexposed resist but works much more slowly on the > exposed resist. Google has lots on this. You can buy caustic soda from > grocery stores or "chemists". -------- -- <http://www.informationclearinghouse.info/article3267.htm> proof that the U.S. media is now state controlled! Ask your' local tv station why the hell they aren't airing the news any more! Our system of government requires an informed public, with their eyes open. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads