15 Feb
2013
15 Feb
'13
12:47 p.m.
On 02/15/2013 12:26 AM, Dave McGuire wrote:
I've definitely heard of copper sulfate as an
etchant. I've never
used it, though, and don't know anything about it. Definitely heard of
it in that context though.
Then you're one up on me. I've used it in electroplating (pretty blue
crystals) and in etching zinc and tin, but not for etching PCBs. You
can use it as a source of copper ions to prepare a solution (usually
using HCl) with the [CuCl4]2? complex, which is an excellent PCB
etchant. But many copper salts--even elemental copper--can do that.
But I can put a PCB in a solution of CuSO4 and nothing remarkable will
happen.
Here's a nice video showing the chemistry of 10 PCB etchants. Some are
really nasty and you'd have to be out of your mind to use them. But
note that CuSO4 only occurs as a source of copper ions in the presence
of an acid or as a reaction product, not the etchant:
http://www.youtube.com/watch?v=Q4tWEse2rDI
--Chuck