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'Re (OT) Etchant (was :PCB exposure unit)'
1999\04\27@070258 by Stuart Meier

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>Use cupric chloride/hydrogen peroxide/hydrochloric acid as etchant. Clean,
>stable, infinite life, cause you can regenerate it time after time.

Sounds good - please tell me more

1999\04\27@135550 by Leo van Loon

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The recipe is as follows:
Chemicals
       35% hydrochloric acid,
       30% hydrogen peroxide,
       CuCl2
The bath contains  more than 50 g CuCl2 per litre 10% hydrochloric acid.
CuCl2 is not easy for sale and expensive, start a bath by dissolving 50 g
bare copper wire in 10% HCl with H2O2.
Put the copper wire in 1/2 L 10% HCl. Add 20 cc 30% hydrogen peroxide and 40
cc 35% HCl. Stir half an hour. Be aware of the possibility that chlorine gas
is formed, work outdoors!!!!!!! When the solution gets 'dark' green, add a
little bit H2O2 and twice as much HCl. Repeat until all copper is dissolved.

Mark the change in colour every time you add hydrogen peroxide. It is the
indicator in the regeneration process. Never add more hydrogen peroxide than
necessary to change the colour from dark to light green. When you add more,
chlorine is formed.
Regenerate by adding small portions of hydrogen peroxide, followed by twice
as much hydrochloric acid.

Use the bath at a temperature of 40¡C. The etching speed is mostly dependant
of stirring speed, as with all the other etchants. When more then a few % of
the CuCl2 is changed in CuCl etching speed drops fast, but regeneration is
simple. I stir with bubbles and etch in about 5 minutes. The bath is more
then ten years in use.

You produce cupric chloride. Neutralise the rinsing water and surplus of the
bath with caustic soda (developer). Let the precipitant settle and pour off
the water. The precipitant is quite pure copper oxide when dried.

{Quote hidden}

1999\04\27@155332 by Craig Lee

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Where can I get H202?

This process would sure beat the high prices for etchant charged at
the local electronic's store.

I've been using ammonium persulfate crystals, but I do notice that they
don't work as well as the Iron solution.

Craig

> {Original Message removed}

1999\04\27@155725 by mwestfal

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Craig Lee wrote:
>
> Where can I get H202?

Hydrogen Peroxide. Get it at your local grocery store.


--

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1999\04\27@163804 by Craig Lee

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Duh.  BTW, I'm a bleached blonde.

Ok.  The percentages, say 10% HCL.  Does this mean
10% HCL and 90% water.

For the peroxide, I have a bottle with the following:

Topical Solution 10 vol. U.S.P. 3% W/V

Is this in-fact a 30% solution?

How many ml in a cc?

thx,

Craig

> {Original Message removed}

1999\04\27@163812 by Sean Breheny

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At 12:56 PM 4/27/99 -0700, you wrote:
>99 01:44:23 pm@
>
>Craig Lee wrote:
>>
>> Where can I get H202?
>
>Hydrogen Peroxide. Get it at your local grocery store.

I think that 30% H202 is required for this etchant. The normal medical H202
is only 2%, 30% is quite a bit stronger and more reactive,they don't sell
it in any grocery store I have ever seen.

Sean


>
>
>--
>
>---------------------------------------------------------------------------
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>Mike Westfall N6KUY
>EraseMExyzzyspam_OUTspamTakeThisOuTacm.org
>mwestfalspamspam_OUTodc.net
>http://www.odc.net/~mwestfal/mike.html
>Linux religious dogma: "The Gates of Hell shall not prevail."
>---------------------------------------------------------------------------
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>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
\--------------=----------------
Save lives, please look at http://www.all.org
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1999\04\27@164137 by Dave VanHorn

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> Topical Solution 10 vol. U.S.P. 3% W/V
>
> Is this in-fact a 30% solution?

Nope, it's 3%  30% is around that a hairdresser or taxidermist would use.
Gloves are what you should use, this concentration is a bit nasty.

1999\04\27@165439 by Sean Breheny

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At 02:32 PM 4/27/99 -0600, you wrote:
>Ok.  The percentages, say 10% HCL.  Does this mean
>10% HCL and 90% water.

Yes, but I think its by mass,not volume. So, if I am correct,to get a 10%
solution from a 30% one (commonly available as a concrete floor
cleaner,"Muratic Acid"), you would do the following:

Take 100 grams of the 30% HCL,and add it to 270 grams of water (100 grams *
.3 = 30 grams HCL. 30 / (270 + 30) = 10%)

>
>For the peroxide, I have a bottle with the following:
>
>Topical Solution 10 vol. U.S.P. 3% W/V
>
>Is this in-fact a 30% solution?

No, as Dave answered already.

>
>How many ml in a cc?

1 ml = 1 cc, since a liter is a cubic-decimeter (1000 cc)

>
>thx,
>
>Craig

Sean


|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
\--------------=----------------
Save lives, please look at http://www.all.org
Personal page: http://www.people.cornell.edu/pages/shb7
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1999\04\27@171509 by Craig Lee

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thx.

Here's a stumper for you chemistry buffs:

What was the stuff Tommy Lee Jones was making with the coffee
maker in the movie Blown Away.

Craig

> {Original Message removed}

1999\04\28@042416 by Stefan Sczekalla-Waldschmidt

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Hi,

Leo van Loon wrote:
>
> The recipe is as follows:
> Chemicals
>         35% hydrochloric acid,
>         30% hydrogen peroxide,
>         CuCl2

What is the CuCl2 for ?

I used the following recipe multiple times with much success:

770 ml H2O
200 ml HCL 30%
30  ml H2O2 30%

It's pretty fast with compnents at room temperature, and faster if the
Water
more warm.

Disclaimer: Use of of this recipe on your own risk !

Kind regards,

       Stefan

1999\04\28@073218 by Sebastián Dols

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Where can I get H202?
<large-snip>
-------
H202 in a 60% commercial form (be aware and avoid quimical 100% H2O2 because
is *veryveryvery* reactive with light and degrades to  H2+O2, so is
*veryvery* explosive) is usually used by the hair stylists to decolorate
human (women? ;) hair. It looks like a white paste.

HCL 10% is usual as a industrial bath disinfectant (in Spain the name is
'salfuman', I don't know under what name is sold in English). It is light
yellow and smells bad, but don't confuse with ammonia, with the same uses,
that smells like urine.

I never used with the CuCl2, I only use 50% H2O2(hairstylist grade) and 50%
HCL(disinfectant grade). Really cheap, pretty quick mixture. But be aware
with the speed.. it can eat all the cupper of the board in 2 min or less if
too hot. No more than 35-40 Celsius (direct light with a close 100W bulb is
enough) if you appreciate your artwork.

Test it. It works.

1999\04\28@075129 by Stefan Sczekalla-Waldschmidt

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Craig Lee wrote:
>
> Where can I get H202?
>
> This process would sure beat the high prices for etchant charged at
> the local electronic's store.
>
> I've been using ammonium persulfate crystals, but I do notice that they
> don't work as well as the Iron solution.
>

I heard that ammonium persulfate workes best at 600 Celsius - but
I never tryed because the HCL-H2O2-H2O mixture I use fitts my
needs at 200 Celsius - means no need for additional heating.

Kind regards

       Stefan

1999\04\28@080555 by Sebastián Dols

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I heard that ammonium persulfate workes best at 600 Celsius - but
I never tryed because the HCL-H2O2-H2O mixture I use fitts my
needs at 200 Celsius - means no need for additional heating.

Kind regards

       Stefan
-------
mmmm.. 200 celsius degrees is 473'6 Kelvins. Where is the water at these
temperature?. At 600 Celsius maybe I would be able to pay to see it. It can
be really funny to put something into that...

1999\04\28@082248 by Stefan Sczekalla-Waldschmidt

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Hi,

Sebastian Dols wrote:
>
> I heard that ammonium persulfate workes best at 600 Celsius - but
> I never tryed because the HCL-H2O2-H2O mixture I use fitts my
> needs at 200 Celsius - means no need for additional heating.
>
> Kind regards
>
>         Stefan
> -------
> mmmm.. 200 celsius degrees is 473'6 Kelvins. Where is the water at these
> temperature?. At 600 Celsius maybe I would be able to pay to see it. It can
> be really funny to put something into that...

Ooooops -  the degree char is handled in a wrong way -

Text should be:

... workes best at 60 degree Celsius ...

and:

... needs at 20 degree Celsius -


Kind regards,

       Stefan

1999\04\29@020245 by Dr. Imre Bartfai

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Hi,
200 Celsius (!) is not a typo? Water begin to boil at 100 Celsius. Frying
pan is about 180 Celsius... It is interesting for me bcus I'd like to know
what did you mean.
Regards,
Imre


On Wed, 28 Apr 1999, Stefan Sczekalla-Waldschmidt wrote:

{Quote hidden}

1999\04\29@044646 by Leo van Loon

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{Quote hidden}

take 110 grams of 30% HCl, and add it to 200 grams of water:
100 grams * .3 = 30 grams HCl; 30 / (200 + 100) = .1 (10%)


{Quote hidden}

1999\04\29@165524 by Snail Instruments

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>Where can I get H202?

I would try drug store first, then pharmacy (maybe you get only 6% or 3%
dilute solutions there). Otherwise companies like Aldrich, Fluke, but these
may be quite expensive.

Josef Hanzal


======================================================================
Electronical devices for chemical laboratory, custom electonics design
----------------------------------------------------------------------
Snail Instruments                     Josef Hanzal, M. S.
Vojanova 615                          phone/fax: +420-311-24433
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Czech Republic                        URL: http://www.vitrum.cz/snail/
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1999\04\29@165708 by Snail Instruments

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>Use the bath at a temperature of 40¡C. The etching speed is mostly dependant
>of stirring speed, as with all the other etchants. When more then a few % of
>the CuCl2 is changed in CuCl etching speed drops fast, but regeneration is
>simple. I stir with bubbles and etch in about 5 minutes. The bath is more
>then ten years in use.

Just a little correction - I am almost 100% sure, that ceased etching
activity is more likely due to decompousing (and consuming) hydrogen
peroxide then to formation of CuCl. The dark green color is caused by
formation of complex [CuCl4]2- anions.

A little math shows, that you need about 0.75ml of 30% H2O2 and 1.25ml of
35%HCl to etch 1 sq inch of 2oz PCB, assuming 100% conversion. Since the
peroxide slowly decompouses, it is correct to use excess of it.

BTW, already mixture of HCl and H2O2 etches copper. The role of cupric
chloride is quite unclear, since it is the product of the reaction, not one
of the reactants.

Etching:
Cu + H2O2 + 2HCl --> CuCl2 + 2H2O

H2O2 Decompousing:
2H2O2 --> 2H2O + O2

Josef Hanzal


======================================================================
Electronical devices for chemical laboratory, custom electonics design
----------------------------------------------------------------------
Snail Instruments                     Josef Hanzal, M. S.
Vojanova 615                          phone/fax: +420-311-24433
266 01 Beroun                         e-mail: snailEraseMEspam.....iol.cz
Czech Republic                        URL: http://www.vitrum.cz/snail/
======================================================================

1999\04\30@063348 by Leo van Loon

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Never try!!

Leo van Loon
SBB simpeltronics
Netherlands
tel +31 (0481) 450034
fax+31 (0481) 450051
mail EraseMEsbb.simpeltronspamtip.nl
url http://www.sbb-simpeltronics.nl
SBB simpeltronics ontwikkelt technische projecten voor basisschool en
basisvorming.
SBB simpeltronics develops technical projects for children in primary and
secondary education.

{Quote hidden}

This list is not the place for this discussion, but there is enough evidence
in literature that copper plays the main role in this process. In fact in my
process, hydrogen peroxide is not present when etching.

But, a mixture of 35% hydrochloric acid and 30% hydrogen peroxide is deadly
dangerous. When hydrogen peroxide starts to oxidise the hydrochloric acid
you even don't have the chance to smell the chlorine gas. Sunlight, a trace
of iron or a hot spot can trigger this process.





> A little math shows, that you need about 0.75ml of 30% H2O2
> and 1.25ml of
> 35%HCl to etch 1 sq. inch of 2oz PCB, assuming 100%
> conversion. Since the
> peroxide slowly decomposes, it is correct to use excess of it.

Peroxide reacts very fast as oxidant

>
> BTW, already mixture of HCl and H2O2 etches copper. The role of cupric
> chloride is quite unclear, since it is the product of the
> reaction, not one
> of the reactants.

Who knows?

>
> Etching:
> Cu + H2O2 + 2HCl --> CuCl2 + 2H2O

This is the overall result anyhow


>
> H2O2 Decomposing:
> 2H2O2 --> 2H2O + O2

This happens in the H2O2 bottle. Do not screw the cap tight!



{Quote hidden}


'Re (OT) Etchant (was :PCB exposure unit)'
1999\05\03@043154 by Benjamin Petersen
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> >Where can I get H202?
>
> I would try drug store first, then pharmacy (maybe you get
> only 6% or 3%
> dilute solutions there). Otherwise companies like Aldrich,
> Fluke, but these
> may be quite expensive.
>
> Josef Hanzal

I pay $5 for 500ml in 40%

Regards
 Benjamin Petersen

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