"Ecnerwal" wrote in
message
...
In article ,
"Edward Hennessey" wrote:

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock,
the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Spread it out as thin as possible in your vacuum chamber (ie, a
bunch of
petri dishes would be much better than a beaker, say) and give it
some
time under vacuum. My personal analysis of the best way to do this
has
always proved more complex to implement than has been worth it
anywhere
I've needed to do this - that would be to pour the epoxy from one
container to another (or directly into the mold in the case of
molded
parts) while under vacuum, and thus gets into mechanical seals and
or
electrical apparatus to facilitate pouring while under vacuum. Can
be
done, just more money and bother than has been desired to expend on
this
detail.

--

E:

Vacuum degassing the resin in a flat dish would be possible. Any hint
at the level
of vacuum best used?

Because the fossil substrate that takes the pour is very large, the
prospect of building
a sizeable air-tight chamber is not one preferably contemplated.

Regards,

EH