"Royston Vasey" wrote in message
. au...
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'm using CW177 resin & HY177 hardener in the 5:1 mix recommended.

The data sheet is he

http://www.meury.com.au/uploads/170666853166.pdf

I tried some rapid set epoxy (~90 seconds) but it turns to crap before I
can get it in where it needs to go.


It's not really practical to use anything else (like RTV, tape, hot glue
or wax etc) to seal the small gaps in the bottom of the assembly.

Has anyone played around with this type of problem?

thanks.

As Lloyd an others have suggested, straight epoxy is going to be a problem
if you need to overcome its tendency to run. In fact, it's inherently
anti-thixotropic -- just the opposite of what you want. Epoxy drools.

The two usual solutions are to add a thickener, which doesn't directly
address the problem but which slows down the running, or to add a
thixotrope. That's the better solution in most cases although you have to be
careful because the suppliers usually aren't very clear about what their
products actually do -- thicken it, or make it thixotropic. There are a
couple of other possibilities, like rotating the part slowly while it's
curing, or applying the epoxy in steps, to one plane at a time, and making
sure the plane to which you've applied it is held horizontal while it's
curing. I can't picture your application but it sounds as if these solutions
wouldn't work for you.

Not being up on the latest, I can't give any specific recommendations, but
I'd follow the suggestions of people who understand the difference between
these two properties.

--
Ed Huntress