Adam,
It might be a question related to what kind of dryfilm resist one is
haveing. I so far only had the ocasion to try two different products.
One was from a british manufacturer (don't know exactly anymore) and now
I use OrdylAlpha (which is IMHO a product from somewhere in aisa). With
none of the two I ever had the case that the exposure side polyester
film came off first and I did many many many times already. In fact,
with the products I used so far, the backing layer comes of very easily,
that said I use those tape stripes probably for 10 PCBs up until I
change them. Removeing the sticky tape on the exposure side is no
problem either because it sticks in the area that I later press to the
typewriter paper (in other words to an area that is cut off anyways
after lamination). I may should also say that the average area that I
ever cover with tape is as smal as aproximately 5 x 5mm on one of the
corner sides.
I could not imageing doing this with tweezers, but this IMHO is a
perfect sample for the fact that many roads lead to rome :-) I mean the
most important thing is that the problem gets solved and I'm glad we
could show at least two ways to savely do it so anyone who is new into
this might pick the method he feels most comfortable with.
Markus
Adam Seychell schrieb:
>
> 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
> <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
>
>