Hello Mebo,
The latex paint you tried, was that normal house paint, or a special
type?
I ask because I still have some special latex ink here, which was
designed for rotring / steadler plotting pens. I once tried it on a
PCB and it seemed to be reasonable waterproof and adhere to the
copper. I also tried because I want to test already for a long time
printing using inkjet on a PCB.
The make of it was rotring, but I don't know if it's still in
production. Probably not, since most plotters are not.
I will hopefully find the time to continue on this project as well in
the near future, but in the meanwhile I follow your progress with
great interrest.
I also know this company
http://www.refillink.com/ do waterproof
inks, at least they do in the netherlands. It's for an HP type of
printer, but might as well work in the epson. Or maybe the stated
printer can be converted as well.
I will try to get some of this ink sometime to try it.
Regards,
Gertjan