"dadiOH" wrote:


I've been using glass & epoxy to effect some repairs. One surface
was very irregular so the plan was to trowel on thickened epoxy,
smooth on the glass squeezing out any thickened epoxy then add
unthickened epoxy if necessary to wet out the glass.

I normally use Cab-o-Sil to thicken but this time I used micro
balloons. After I finished there was maybe 1/4 - 1/2" of both
thickened and unthickened in little pot pie type pans. The thick
went off like gang busters...once it started, it got rock hard in
minutes. It also expanded by about 3X. Meanwhile, the unthickened
had barely gotten syrupy.

What's going on with that? The fast hardening and - especially -
the expansion.
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I'm clueless, but based on your description, sounds like thermal run
away caused the expansion.

I like to use slow hardener with microballoons and limit thickness to
1/4" max per pass.

Using Cab-O-Sil to thicken produces a patch that is a BEAR to sand.

Can you talk to your supplier's tech service group?

Lew