Hmm, I tried that and it seemed to clump up. Maybe its the brand of glue or the water or something. Or maybe it was the white microballon's? That may be it white glue doesn't seem to wet fiberglass too well so maybe it doesn't work with glass ballons only phenolic?

I will have to try that. That way you could use water to smooth it out instead of alcohol with epoxy and microballons.