As an FYI, I realized recently that talc has one disadvantage as a filler. Being ground up rocks, it's really heavy. I realize that you shouldn't end up with much on the plane, but still...weight is weight. Next time, try zinc stearate. You can get it from chemical supply places or Tom Dixon in Atlanta.

And I am playing with #410 filler from West Systems right now and thinking it will be good, too. It is like 1/16th the weight of talc and sands very nicely.