Homebrew PCBs

Hi Adam - my chemist friend (who, incidentally, grew up near Bondi
beach) advised me some time ago to try this recipe. I did not get past
trying some copper in muriatic acide, and, expecting a quick reaction
and getting none, giving up. (He had no idea about the time frame
required, and no suggestions about what to do next). Here is his
recipe, FWIW:

"Dissolve 67 grams of copper in 100 gms muriatic acid solution (the
38% stuff). You could use an excess of copper to make sure all the HCl
is consumed, but make sure you can remove the residual copper. Add 100
gms muriatic acid and bubble the bejeezus out of it until it turns
green. Add an additional 90 gms of muriatic acid solution and 606 gms
of water and you should have about 900 mils of the recipe mentioned in
the Rex Allers article."

I think he got the 38% figure for the HCl from the article, since the
muriatic acid available in hardware stores here is 20 Baume, about 30%.

I don't know if that is helpful or not. He develops plastics for
Dupont, so this is off the beaten track for him.

Thanks for the idea for pumps for hydroponics - I will check  it out

Grant

--- In Homebrew_PCBs@yahoogroups.com, adam Seychell
<adam_seychell@y...> wrote:
> I did another test. This time I simply put clean copper 
> metal in the 20% acid and bubbled lots of air through it. It 
> took just over 3 hours to completely dissolve the copper and 
> produce a deep green colored cupric chloride etching solution.
> 
> makeup data:
> 
> 40 ml of  26%wt HCl acid
> 20 ml of water
> 8.7 grams of copper.
[snip]
> 
> Adam