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Re: gEDA-user: New user to PCB - what does this error mean?
DJ Delorie wrote:
>> the H2O2 is 35 % (hydroponics supply store).
> Most of us use the 3% you can buy in a drug store. 1 part 37% HCl to
> 2 parts 3% H2O2. If you use 35% H2O2 you can dilute it.
There's no need to dilute the 35% H2O2 -- I pour with gloves and goggles on though...and only add H2O2 to used etchant, never to
acid. 35% H2O2 in the mix does give you speed. You see metal coming off as you stir in the form of wisps of blackish liquid.
To make a new etch bath, add acid to at least 1 part water, dissolve copper in acid, add 10 ml at a time of acid and H2O2
to get colors right. Extra water is unwanted. Your air bubbling method
is probably better than 3% H2O2 for regenerating -- maybe some wait time, but no unwanted dilution. I'll be setting that up next
Blue-black or brown means spent and loaded with dissolved copper.
Emerald or yellow green will indicate enough acid. Bluish will need more acid as well as air or H2O2 to replenish.
Ecosensory Austin TX
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