Hi, I'm trying to etch a very fine pitch (0.5mm) aluminium stencil for use with SMT printed circuit board making. I've done some reading on the topic and found that the safest way probably is to use a saline sulfate etch and/or use saltwater electro etching.
Q1: I believe the saline sulfate etch can be used without adding electricity to it, but would it make sense to add electricity to a saline sulfate etch to speed up the process or should this only be done with a saltwater solution?
Q2: If I'm using the electro procedure the aluminium plate that should be etch is used as the anode, but what metal makes sense to use as cathode?
Q3: I like to know what chemical reactions that are going on, in order to be aware of any reaction that could led to hazardous/toxic compounds/substances.
So what is added to the solution is:
Al (alumnium anode) +
X (some metal cathode, not sure what to use) +
NaCl + H20 + CuSO4 (electrolyte solution)
(seen suggestions to also add NaHSO4, any reasons why this should help?)
All these are probably split into ions:
Al^(+3) + Na^(+) + Cl^(-) + Cu^(2+) + SO4^(2-) + 2H^(+) + O^(-2)
Know how can I tell which reactions that are going to take place? From googling+guessing i think i might end up with some of the following:
AlCl3 + Cu + Na(SO)4 + H20 + Al(OH)3 + NaOH + Cl
The reaction most likely to take place has something to do with number of electrons in the outer most shell? It has been 15 years since i have had chemistry in high school, so i cant remember much of this stuff any more. Hope you can help
Best regards
conner