Etchant and PCB

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HCL + H2O2

This is a very active etchant and you should be able to get the hydrogen peroxide (not the pharma strength, more like beauty supply store strength) and hydrochloric acid pretty easily up in Northland. There is a thread at www.groups.yahoo.com/group/Homebrew_PCBs/
which discussed the chemistry.<p>I've heard of it being used, but never tried it.I guess the best thing
for you to do is try it yourself.<p><em>
In Australia, H2O2 is available from commercial hair dressing suppliers
in about 18% (wt) and sold in 250 ml to 5 liter. The HCl is brick
cleaner, ect and available in most hardware shops, in anything from
250ml to 25 liter and cheap too. HCl is almost always sold concentrated
about 30 to 35% (wt). So going by the reaction

H2O2 + Cu + 2HCl -> CuCl2 + 2H2O

and 30%(wt) HCl = 8.2 Molar, 18% H2O2 = 5.3 Molar
for every mole of H2O2 you need two moles of HCl. i.e ratio of hardware
store acid and hair dressing peroxide is approx.
volume acid * 8.2 = 2 * volume peroxide * 5.3
or
for every liter of 18% peroxide you need 5.3 * 2 / 8.2 = 1.3 liters of
30% HCl solution.
<p></em> I can't vouch for it, but if you do a google search the formula shows up over and over again.
 
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