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Subject: RE: [Bulk] Re: [Homebrew_PCBs] Muriatic Acid and 3% Hydrogen Peroxide First Attempt

From: "Mike Law" <myclaw86@...>
Date: 2014-04-11

Just to chip in my 2 cents:



25% HCl (in the UK, maybe ask for "spirits of salt" at the hardware type
shop). 3% peroxide from the chemist. First etch - nice and quick. All
further etches, not worth bothering with - think overnight!



So I went on Ebay and got the food grade 35% H2O2 peroxide. Outside,
raining, temp not much above 10∗C (I was in the garage, so it wasn't raining
on my PCB!). Threw in H2O2 until it went the lovely emerald green colour.
Chucked in the board, got a stick to swish stuff around, and yeah - like
Dexter's Lab - bubbles, smoking, all very exciting.



For those with bubble tanks, etching many boards, I'd pay attention to
specific gravity and all the fancy sciency bits. For people like me who
want a board every once in a while: get the acid, throw in some stupidly
strong peroxide and swish it about a bit until it "looks right". Obviously
it doesn't go green until you've got some copper in there, so don't go made
to begin with. I like the foam brush idea, I'll try that (or a sponge) next
time. But don't faff about with 3% peroxide in my opinion, just throw in
something stronger and have fun with the bubbling and smoking! J



Mike



As an aside, HCl for cleaning stubborn stains from lavatory pans is
excellent. Throw it on, leave for 20 mins, rinse off. Sparkling loo, zero
effort!



From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Harvey White
Sent: 11 April 2014 03:21
To: Homebrew_PCBs@yahoogroups.com
Subject: [Bulk] Re: [Homebrew_PCBs] Muriatic Acid and 3% Hydrogen Peroxide
First Attempt





On 10 Apr 2014 11:09:00 -0700, you wrote:

>I just tried another version of etchant solution. 1. Lowels lumber yard
Crown Muriatic Acid and 2. Drug store version of hydrogen peroxide 3 % type.
Mix 1 & 1/2 cup muriatic acid and 3/4 cup hydrogen peroxide in a plastic
tupper ware container. My board size was equal to 4 in. times 8 in. Time
> around. 30 min. My question is I do not know the strength of the Crown
version
> of the muriatic acid. Is this time normal and is there a way to speed up
the time the board is in the tray

I think less muriatic acid and more H2O2, say 1 part to 4 parts or 1
part to 3 parts.

Harvey





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