Homebrew PCBs

Markus Zingg wrote:
> I created a little photoalbum showeing the process. I don't know if the 
> link below will work (had some troubles in the past with it here) and as 
> always, the group moderator first must aprove the pictures but still...
> 
> http://tech.ph.groups.yahoo.com/group/Homebrew_PCBs/photos/browse/b99e

thanks for the photos. I see you don't have problem with resist sticking 
to the copper at cold regions of the board.

> Note, Adam describes that he uses pliers to seperate the protection foil 
> from the laminate. I always use electric isolation tape for this 
> purpose. I cut two short pieces off, stick a very small part of one to a 
> corner of the laminate, then stick the second one to the oposite side 
> and tear the two apart. Since the tape sticks harder to the laminate and 
> protection foil than the protective foil to the laminate the two 
> seperate easily. I thereafter remove the tape. Note, I always use the 
> part of the foil that I stick onto the typewriter paper (see in the pics).

I once tried your method and found the sticky tape would pull the thin 
protective exposure side polyester film instead of the backing layer 
which is a thicker polyethylene film. Even so, you now have to safely 
remove the sticky tape that is now stuck to the exposure side film.

I found tweezers was the way to go. But then another problem was when 
peeling away the backing film is a good chance the photoresist film 
curling back on its self rendering it useless (similar to how sticky 
sides of sticky tape making contact, i.e impossible to separate). The 
dry film photoresist being held by water surface tension on to a sheet 
of laser printer transparency solved the curling back problem from ever 
happening again.


Adam