Homebrew PCBs

On Thu, 22 May 2008 19:08:29 +0100, you wrote:

>Hello Group,
>
>I've been following this discussion with interest and would like to move away from etching pcb's with ferric chloride.
>I live in the UK and wonder if anyone knows of a supplier of the muriatic acid and hydrogen peroxide to home users. My local chemist was no help at all and didn't have a clue.

Home supply stores often have muriatic acid (HCl) for pool cleaning
supplies.  However, the last time I was in the UK, I noticed a
suspicious lack of such things.  You might find it used for cleaning
concrete or bricks, though.

If you have a Walmart or equivalent, you might find hydrogen peroxide
sold in largish quantities as a disinfectant.  It is also possibly
available from beauty supply stores in a higher concentration.


Harvey


>Any help greatly appreciated!
>
>Steve
>  ----- Original Message ----- 
>  From: Michel Baguet 
>  To: Homebrew_PCBs@yahoogroups.com 
>  Sent: Tuesday, May 20, 2008 5:05 PM
>  Subject: Re: [Homebrew_PCBs] H2O2 + muriatic acid etchant?
>
>
>  I'm using HCl for a years. 700cc of distilled water, 270cc of HCl highly concentrate (you can see smoke when the bottle is open) and 30cc of H202 at 30% concentration.
>  The only problem with this etchant is that H2O2 decompose with heat and light and if you etch another board a few days later, you don't know what part of H2O2 is still in solution. So I put the board to etch in the tank and take it out to see the color of the copper. If there is still enough H2O2, it must turn brown immediately.
>  If not, I add 10cc and son on but never more than 30cc (obvious !).
>  But the cost of HCl, H2O and H2O2 is so cheap that I often replace the etchant, to always get accurate results with small traces. A 200cm\ufffd double sided board with 35\ufffd copper take between 4 to 6 min. in bubble etch tank @ 45\ufffdC.
>
>  clintonlcorbin <clcorbin@...> wrote: Folks,
>
>  First, I want to say "Hi". I just recently started making my own
>  single and two sided PCBs and even more recently joined the group. 
>  There is a lot of great info here!
>
>  The question I have regards the etchant I have been using: 1 part
>  muriatic acid and 2 parts H2O2 (hydrogen peroxide). I found the
>  formula on a web page about (what else) DIY PCBs. As I was wanting to
>  try making my own PCBs and the materials were easy to obtain and low
>  cost, I decided to give it a try.
>
>  All in all, I have been quite happy with the results so far. I
>  haven't tried any real fine line etching yet and the smallest SMD
>  devices are 0603, so they are pretty big. The etchant is clear, so it
>  is very easy to keep your eye on the board during the etching process.
>  Plus, I have been doing all my etching at room temperature with no
>  heating at all. It generally takes about three minutes to fully etch
>  the small (2x3" are the largest so far) boards I am working with.
>
>  So the questions are:
>
>  1) How does this etchant compare to more traditional etchants?
>  2) Does it have over etch / under etch issues with finer lines?
>  3) Anything else I should be aware of?
>  4) Anyone else used this etchant along with the others that can give
>  a pros/cons?
>
>  Thanks for the help and all the info in this group.
>
>  Clint
>
>
>
>
>
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>
>
>
>   
>
>
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