How about diatomaceous earth as a filler.
It is the skeletons made of silica of microscopic creatures from long ago.
Has anyone tried this as a filler? I would think it would be good and cheap.

"John Cassara" wrote in message
...
I need to fair large deck surfaces in prep for paint. The repair thus far
has been all polyester, can I use microballons to create a polyester
fairing compound?

John