Homebrew PCBs

"James" <jamesrsweet@...> writes:
> What are you using to hold your film to the blank PCB?

Thin glass plate with 3-8 in Hg vacuum.  Holds it very tight against
the PCB.

> You have to make sure the printed side is against the board,

Always do.

> printers have trouble getting a nice solid black on transparency
> film too, vellum paper tends to work better,

I didn't have any luck with vellum, the laser printer didn't put down
much toner and ink just smeared.  I'm using Jetstar film with an
inkjet, I can do 100% coverage at 2880 dpi and get *fantastic* prints
off it (even under a microscope).  Gives about 8 steps on the 21-step
scale so I know the ink print is good.

The UV film after developing looks great too, it just makes traces
that are smaller than the film by about 1-2 mil on each edge, which is
enough on a 6 mil trace to not leave enough surface area for the film
to hold on, and it etches completely through.  I figured maybe the
film's edge had something to do with it.