Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, lists <stuart.winsor.lists@...>
wrote:
>
> In article <f2pf25+oulj@...>,
>    lcdpublishing <lcdpublishing@...> wrote:
> > Anyway, I ordered up some negative type resist chemical
> 
> If you're talking about spray on type stuff forget it. It's well nigh
> impossible to get an even coating of consistant thickness without
> pin-holes and other flaws.

It's been many years since I've made boards that way, but I didn't
have any particular problems with spray on negative resist.

BTW- black inkjet ink is not the most UV opaque. It has been posted
here several times in the past, I learned it from someone using an
inkjet printer to make photo films for Tshirt screens.

The basic idea: the ink that is most sensitive to UV fading are the
photo magenta and photo cyan. So OEM inks that have improved fade
resistant must have UV blockers. I even saw a website where someone
tested this, and he found that printing a light green resulted in the
most opaque (to UV) patterns.

Also, look at what pro Tshirt screeners use: vellum. They tend not to
use transparencies.

Check out http://boards.screenprinters.net forum.

Steve Greenfield