Re: Questions about etching aluminum and copper plates
I never had good luck with acrylic inks as a resist using the copper sulfate mordant ... it always seemed to lift, no matter how well I cleaned the plate. I have used standard oil base inks with added cobalt drier. Paint the plate and leave it overnight to "dry". The only problem with oil based inks is removal ... try acetone or TSP if the paint has not been dried for too long. Do not use products containing lye, as that will etch aluminum. I generally do not do really fine line etching ... my favorite resist is ordinary shellac. Apply an even coat, let dry for 15 minutes, and you are good to go. It removes easily with d-limonene based cleaners ... i.e. citrus cleaners.
Cheers ...... Charles