Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Just attempted my first photofabrication and it failed at the
developing stage. Within 30 seconds of immersion the board was
completely devoid of resist...

Here's what I did (all M.G. Chemicals supplies)

-Printed out my circuit onto a transparency (IBM Laser
Transparencies, 24L5041) using a Samsung ML-1210 laser printer.
-Poured two litres of hot tap water into a tray.
-Poured 200ml of Developer into the tray of water (10:1 as per
instructions).
-Set up the UV light using the supplied stands (about 5-6" high).
-Placed the sensitized board blue side up. Positioned my
transparency (ink side toward the board) and placed the plexi weight
on top.
- Waited 5 minutes then turned out the light (actually probably more
like 5.5 minutes).
- Immediately put the board into the developer solution. I used the
supplies foam brush to agitate the water (didn't come within 1/2" of
the board itself, just slowly waved it back and forth at the
surface). Solution was about 95-100F by this time.
- About 5 seconds in I could see my traces through the clouds of
black ink. As the black ink cleared I could see traces starting to
fade out too. This is about 15 seconds into the process. I realized
the board was already toast so I waited to see how long it would
take to completely erase the resist - was about 30 seconds.

The instructions say it should take about 2 minutes to develop the
board. This was a LOT faster... I'm thinking perhaps the developer
was too strong? What about temperature? Should I just use developer
at room temperature instead - give myself more "OOOOP" time?

I guess its also possible that this laser's toner isn't UV opaque
but, the speed at which the board completely blanked and the fact
that I saw traces - even for a short time, makes me think its a
developer problem.

What do you guru's think?