In article
,
says...
I'll follow up the many helpful messages here.

So I will be sure to find some casting resin with a slow hardener.
Another method of cooling for very large castings is to have some
parting compound loaded copper pipes running thru the piece to get rid
of some more head. The shaker table is something I can probably rig
together quickly. The silane solution, well maybe I'll use it if I
don't get good results. I planned on doing a small test block.
Hopefully this will work out.




The real stuff from Philadelphia Resins, which someone else
mentioned, is not that expensive. IIRC, it's less than
$1/lb for a kit which includes the proper resin &
aggregate.

Ned Simmons