Are you using a real roller-coating machine?
Those photoresists (AQ3000) are intended for professional use and generally does not accept any kind of fake/hobbyiest process.
You could build a dip-coating machine which is much easier to apply than roller-coating.
--- In Homebrew_PCBs@yahoogroups.com, Larry Battraw <lbattraw@...> wrote:
>
> Hi, I recently bought the roller-coating version of this photo resist and am
> having a terrible time getting a board to cure properly. What generally
> happens is that the board will cure somewhat well except for a big, jagged
> "rip" through the center of the board's resist. It looks like a ragged tear
> in the resist and spreads out in sharp edges kind of resembling a lighting
> strike with the streamers of the defect branching out. If anyone is
> interested I can post a picture of the problem. Has anyone used this stuff
> and had any success with it? I've tried diluting it since it tends to
> capture bubbles like crazy when spread normally but that just results in a
> pool of concentrated resist in the center of the board and decreasing
> amounts as it reaches the edges of the board. I would really appreciate
> some hints since the stuff has great potential to coat large/thick boards
> that won't fit in a normal laminator with the dry film resist.
>
> Thanks!
> Larry
>
>
> [Non-text portions of this message have been removed]
>