On Sat, 03 Aug 2013 13:37:58 +1200, you wrote:
>On 3/08/2013 9:16 a.m., Philip Pemberton wrote:
>>
>> On 01/08/13 02:33, Harvey White wrote:
>> > Why bother to go that way when the copper from the boards you would
>> > etch would do the same, and get the boards etched? With a lot of
>> > oxygen available, you'll find that these boards will etch rapidly in
>> > the fresh mixture. As the O2 from the peroxide dies off, the bubbled
>> > air will substitute for that and you're building your CuCL2 etchant.
>>
>> I mixed the stuff up yesterday, but I think the etchant might be a bit
>> short on oxygen - after an hour or so it turned a dark brown and pretty
>> much stopped reacting with anything.
>>
>> I've left an aquarium air bubbler running overnight with the copper
>> removed. I'll see what that does but it doesn't look promising and I'm
>> out of H2O2... :-/
>>
>
>Try some sodium percarbonate, 1 teaspoon/50ml of water, readily
>available as a cleaning agent. Add very slowly as it releases CO2 and O2.
Not sure that this will work, but potassium persulfate is an etchant
in and of itself. In the states, it's used as a shock treatment for
swimming pools (the extra oxygen kills off stuff you don't want).
It's about the equivalent of 3 GPB per kilo, and as such (you need
almost that much for a single run), is rather expensive when compared
to muriatic acid/hydrogen peroxide mix. The rather expensive (when
new) etchant tank I have can't handle the HCL.
So does sodium percarbonate work as an etchant?
Ammonium persulfate and potassium persulfate (with trace ingredients)
are used as etchants. The trace ingredients come when you buy the
stuff to treat pools (and they don't tell you what is.....).
The persulfate etchants do not attack tin/lead, if I remember it
correctly.
Harvey
>
>> Thanks,
>> --
>> Phil.
>> ygroups@... <mailto:ygroups%40philpem.me.uk>
>> http://www.philpem.me.uk/
>>
>>
>
>
>
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