Royston Vasey wrote:
I'm trying to seal a printed circuit board into a PVC part I've turned out
on my lathe. The problem I'm having is the that the epoxy goes quite runny
as it goes through its curing process and some of it runs through small gaps
( 0.5mm) where I'd prefer it didn't.
I do this for vacuum feed-throughs and use Huntington Mechanical Labs
Vacuum Epoxy. It is much thicker that many other epoxies so it stays
put better. It is hard stuff, so it can crack if the assembly is made
to flex. The Huntington stuff is apparently the same as Varian's famous
Torr Seal, but about 1/4 Varian's price. Huntington has a minimum order
that may make this unreasonable for a one-off home project.

A trick is to seal up the bottom of the assembly with 3M magic tape
before applying the epoxy. it sticks just well enough to keep the epoxy
from flowing out the bottom.

Jon