Homebrew PCBs

Thank you for the reply, I found it very interesting.  As you say part of 
the answer is in cleaning or preparing the copper surface but most of my 
problems lay with the ink.  I got in contact with many ink manufacturers and 
we had some rewarding discussions about this application.  It basically 
boils down to the choice between a solvent based ink or an UV cured ink. The 
water solvent based inks I have tried so far, simply wash off in the acid 
bath. There can also be a problem with the solvent vaopurising and cloggung 
the head. I came to the conclusion that a UV cured ink may be a possible all 
round solution. These are actually resin based and offer a much more durable 
printed image. UV inks are available that will cure in a fraction of a 
second. So it might be possible to mount a fibre bundle from a UV light 
source to just behind the print nozzles as a low mass light cure source.
            Taking the idea one step further, it would also be possible to 
print, graphics, flux as well as acid resist direct onto the board. This 
leads us onto conductive inks, which already exist.  They normally require 
special for purpose heads, but seem to work well for most low power 
applications. I think for my own purposes a simple A5 flat bed printer, 
using UV cured ink would do the trick. Another advantage of UV ink is that 
it does not dry in the nozzles as solvent ink does. I have seen applications 
where multilayer boards have been produced using UV inks, with an insulating 
ink between layers ... and all of this printed on a flexible substrata. 
Anyway who says we have to have a purpose substrata since we can print onto 
anything!
             It is possible to convert the older models of Cannon printers 
into flat bed, I have one on the bench at the moment. Thanks again for the 
reply. .

John.
----- Original Message -----