> After building my Arctic Tern, I paid more attention to the technique used
> in other boats, especially the local Michigan-made Betsie Bay plywood
> kayaks. I was suprised at the size of the fillets that are generally used.
> The ones I put in my Pygmy measure only about 1/2" across, so there's
> still a fairly sharp transition as you go from panel to panel. But the
> Betsie Bays use very large fillets, measuring more like 1 1/2"
> across. There's a lot of epoxy there, but their boats are still very
> light-weight. I'm not sure what kind of fillers (wood flour, Cab-O-Sil,
> etc.) they use.

Micro-ballons problably.