On Sun, 19 Oct 2003 23:49:33 GMT, "Brian D"
wrote:

Actually, if you mix microballoons into it until it looks very nearly thick
enough (soft peanut butter), then you'll find that only a little silica will
keep it from sagging. Estimating from my own work, I'd say about 85%
phenolic microballoons plus about 15% silica, by volume.

Brian

Exactly. Don't go mixing it with 100% silica just because it's
vertical. I've seen people do it. I think they're still sanding.

-m