Homebrew PCBs

> Phil wrote:
>
> <SNIP>
>
> Before applying the film I  fill the holes
> with a mixture of drywall plaster and sugar,
> let it dry, and sand the board lightly to
> remove any plaster from the surface. This
> provides a flat surface for the resist film,
> and is easy to remove with water and a 
> water-pik (dental cleaner) after etching.
> The sugar resists the etchant in case any
> does come into contact, which otherwise
> would solidify the plaster making it
> difficult to remove.

Have you had problems with tenting?  How thick
is negative active film you are using?

Thicker film and a good contrast artwork should
make a tent that is plenty strong enough to
survive even vigorous hand developing/etching.