Homebrew PCBs

dkesterline wrote:
> Well, I finaly got around to buyng a jug of acid and trying this out.
> 
> I bought a gallon of HCL (31.25%) from my local hardware store, $2.95 
> (USD) Stopped by the Pharmacy and bought a quart of 3% H2O2 for 
> $0.94. 
> 
> Plastic container, about 1/4 cup acid, stuck in a piece of circuit 
> board and started adding H2O2. At about 1/2 cup I could see some 
> green tinge and the copper started changing. I poured in a litle more 
> (about 3/4 cup total) and the copper etched in about 8 minutes.
> 
> About 1 cup total of etchant removed about 30 sq inches of copper 
> (surplus scrap, but I think 1 oz) before it was quite dark and slowed 
> considerably.
> 
> I think the amount of water in medical grade would prevent it being 
> used to recharge the etchant (to much dilution) but it certainly 
> started it fine. 
> 
> Even if I had to throw it away instead of recharging it, this is 
> still *much* cheaper than Feric Chloride. At these ratios a 94 cent 
> quart of medical H2O2 and a cup of acid would replace a $12 quart of 
> Feric Chloride. 
> 
> I did notice that it was much more unpleasant to be around (lots of 
> nasty fumes) But I can work around that.

Retail shops cost too much. I got my FeCl from an industrial supplier
for ~ US$2/Lt.