Homebrew PCBs

I looked through the files section and didn't see what I am looking
for (it may be there, I just don't know one chemical from another).

I am looking for an etching solution that I can get or make from
common materials (hardware stores, etc.) that works good and is also
clear.

The stuff I have used so far came in the Radio Shack kit and was dark
brown in color - made it very difficult to monitor the etching
process. Others here have mentioned some chemical that is clear and
works good.

Hope you can help!

Chris

On Mon, 18 Jul 2005 21:13:11 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

> I looked through the files section and didn't see what I am looking
> for (it may be there, I just don't know one chemical from another).
> I am looking for an etching solution that I can get or make from
> common materials (hardware stores, etc.) that works good and is also
> clear.
> The stuff I have used so far came in the Radio Shack kit and was dark
> brown in color - made it very difficult to monitor the etching
> process. Others here have mentioned some chemical that is clear and
> works good.
> Hope you can help!
> Chris


You can make CuCl from common chemicals. It is sort of clear (green, but  
you can see clearly with a light).
look in the links.

ST

The clearest etchant I am aware of is ammonium persulphate (AP).  As
it gets consumed, it turns a rather pretty shade of blue but is still
clear enough to see through.

The next clearest is CuCl as stefan mentioned.  I have used it but
found it to be difficult for me to use and recently switched back to
AP.  Even though it isn't opague, I have to disagree with stefan on
the clearness aspect.  It turns an emerald green (also quite pretty)
and unless your etch tank is fairly narrow, it is hard to see through.
  My CuCl tank is about 3 inches wide and I had to lift my boards out
to determine progress.  CuCl also stains though not nearly like FeCl.
 it is also much more agressive to some plastics than the other 2
etchants - probably due to the HCl.  I also was not able to get better
than 30 minute etch times vs 10-12 with AP.

FeCl, which I think you used, is completely opaque and a totally
horrible substance...

I've used all three and much prefer AP even with the disposal issue. 
CuCl is cheap to make if you have an inexpensive source of hydrogen
peroxide but I don't.  Also, with CuCl, you don't have a huge disposal
problem.  AP is the priciest of the bunch (3X CuCl, 2X FeCl).  If I
was making a lot of boards per month, I'd probably go back to CuCl
because of the cost even though I'd have to play chemist.

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> I looked through the files section and didn't see what I am looking
> for (it may be there, I just don't know one chemical from another).
> 
> I am looking for an etching solution that I can get or make from
> common materials (hardware stores, etc.) that works good and is also
> clear.
> 
> The stuff I have used so far came in the Radio Shack kit and was dark
> brown in color - made it very difficult to monitor the etching
> process. Others here have mentioned some chemical that is clear and
> works good.
> 
> Hope you can help!
> 
> Chris

Hi Chris,
    The brown etchant that stains stuff like crazy is called Ferric 
Chloride.
Which is a common hobby etchant.  Another common etchant is Ammonium 
Persulfate
which is clear to start and turns a transparent light blue during the 
etching process. However the drawback with the latter is that
once it is mixed up it does not keep so once you have finished etching a 
batch of PCB's you have to discard of the etchant.

By your own admission "I just don't know one chemical from another" I 
would strongly recommend using the commercially
available etchant as they are not _that_ expensive. Mixing you own 
etchants involve using chemicals that are quite dangerous
if not handled properly.  For example, are you aware you should never 
add water to acid. ALWAYS add acid to water!  Once you
have the etchant there is more chemistry in correctly maintaining it.

If it is just increase visibility of the etching process then get 
yourself some Ammonium Persulfate. With this you can easily monitor the
etch process.

Cheers,
David





lcdpublishing wrote:

>I looked through the files section and didn't see what I am looking
>for (it may be there, I just don't know one chemical from another).
>
>I am looking for an etching solution that I can get or make from
>common materials (hardware stores, etc.) that works good and is also
>clear.
>
>The stuff I have used so far came in the Radio Shack kit and was dark
>brown in color - made it very difficult to monitor the etching
>process. Others here have mentioned some chemical that is clear and
>works good.
>
>Hope you can help!
>
>Chris
>
>
>
>
>
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBs
>
>If Files or Photos are running short of space, post them here:
>http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
> 
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>Date: Mon, 18 Jul 2005 19:13:11 -0000
>Subject: [Homebrew_PCBs] Etchant solutions - home-brew questions...
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>
>I looked through the files section and didn't see what I am looking
>for (it may be there, I just don't know one chemical from another).
>
>I am looking for an etching solution that I can get or make from
>common materials (hardware stores, etc.) that works good and is also
>clear.
>
>The stuff I have used so far came in the Radio Shack kit and was dark
>brown in color - made it very difficult to monitor the etching
>process. Others here have mentioned some chemical that is clear and
>works good.
>
>Hope you can help!
>
>Chris
>
>
>
>
>
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBs
>
>If Files or Photos are running short of space, post them here:
>http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
> 
>  
>  
> -0-0-0- 
>  
>

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> The clearest etchant I am aware of is ammonium persulphate (AP).  As
> it gets consumed, it turns a rather pretty shade of blue but is still
> clear enough to see through.

Is this (AP) something that you can make from common products or is it 
something you purchase for this purpose?

Thanks

Chris

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
> I looked through the files section and didn't see what I am looking
> for (it may be there, I just don't know one chemical from another).
> 
> I am looking for an etching solution that I can get or make from
> common materials (hardware stores, etc.) that works good and is also
> clear.

Heh, heh... you didn't look very hard. First folder:

http://groups.yahoo.com/group/Homebrew_PCBs/files/Acid_Etching/

I saved instructions someone posted on the list on making CuCL from
muriatic acid from the hardware store (brick and wood cleaner) and
hydrogen peroxide from the drug store.

Steve Greenfield

----- Original Message ----- 

From: "lcdpublishing" <lcdpublishing@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, July 18, 2005 11:36 PM
Subject: [Homebrew_PCBs] Re: Etchant solutions - home-brew questions...


> --- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
>> The clearest etchant I am aware of is ammonium persulphate (AP).  As
>> it gets consumed, it turns a rather pretty shade of blue but is still
>> clear enough to see through.
> 
> Is this (AP) something that you can make from common products or is it 
> something you purchase for this purpose?

You have to buy it.

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller


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In the usa it's around $15-18 per Kg and that make 4 liters of
etchant.  enough for about 40-60 smallish boards.

I've bought my last one from Frys for around $14 and you can get it
online for a bit more.  here, for example:
http://www.circuitspecialists.com/prod.itml/icOid/2825

Phil

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@b...>
wrote:
> ----- Original Message ----- 
> From: "lcdpublishing" <lcdpublishing@y...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Monday, July 18, 2005 11:36 PM
> Subject: [Homebrew_PCBs] Re: Etchant solutions - home-brew questions...
> 
> 
> > --- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> >> The clearest etchant I am aware of is ammonium persulphate (AP).  As
> >> it gets consumed, it turns a rather pretty shade of blue but is still
> >> clear enough to see through.
> > 
> > Is this (AP) something that you can make from common products or
is it 

> > something you purchase for this purpose?
> 
> You have to buy it.

On Mon, 18 Jul 2005 23:51:05 +0200, Phil <phil1960us@...> wrote:

> Even though it isn't opague, I have to disagree with stefan on
> the clearness aspect.  It turns an emerald green (also quite pretty)
> and unless your etch tank is fairly narrow, it is hard to see through.
>   My CuCl tank is about 3 inches wide and I had to lift my boards out
> to determine progress.


Ah yes, might well be too opaque with 3 inches. mine is onlyabout one inch.
If i don't etch when the sun is shining through the window i use a  
flashlight to see the progress.
No trouble seeing through.

ST

On Tue, 19 Jul 2005 00:36:33 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

>
> Is this (AP) something that you can make from common products or is it
> something you purchase for this purpose?
> Thanks
> Chris


Purchase as powder, mix with water, later discard.

ST

David Cureton wrote:
> 
> By your own admission "I just don't know one chemical from another" I 
> would strongly recommend using the commercially
> available etchant as they are not _that_ expensive. Mixing you own 
> etchants involve using chemicals that are quite dangerous
> if not handled properly.  

Depends what your making. If you decide to make some ammonium persulfate 
then it doesn't require or use dangerous chemicals at all, just boring 
old ammonium sulfate, the stuff for fertilizing your garden.


For example, are you aware you should never
> add water to acid. ALWAYS add acid to water!  Once you
> have the etchant there is more chemistry in correctly maintaining it.

Don't have to be acid. Every tried adding about equal parts warm water 
to sodium hydroxide ?   :)

Once I added a pinch of 99% sodium hydroxide to a few drops of 99% 
sulfuric acid. I wanted to see what happens when pure strong acid comes 
in contact with a pure strong base. Standing about 5 meters away when 
the NaOH the crystals were added they initially just floated without any 
reaction. About 10 seconds later the violent exothermic reaction 
started, giving cracking sounds which almost seemed to break the glass 
beaker. Most of the NaOH was blown away, but what did react caused a 
thick sulfuric acid mist to rise from the beaker and lingered for 
several minutes around the room.

Adam