"Jon Elson" wrote in message
...
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


Thanks Jon, yeah the magic tape works well, I've done that before. Heat
shrink tubing is useful as well - cut it off when the epoxy has hardened.

I've ended up using some hot glue to seal the base - its a bit messy but
do-able.