: I was going trough some of the pictures in Tom Yost's (Great) site.
: One is of a Sea Glider and part of the description reads:
: "The skin is canvas coated with varnish combined with talc
: powder, linseed oil, and natural pigments. "

: I get the rest, but what is the purpose of the Talc?

On first coats it helps fill the weave of the canvas and give a smooth base for finish coats. The talc is soft and can be easily sanded smooth. But it is usually mixed in with a paint rather than a pigmented varnish. Maybe the guy was trying to make his own paint.

Otherwise, I can't see much use for it in varnish.

PGJ