Try Cabosil (fumed silica) instead of the cotton fibers. The silica will give nice, smooth fillet. Add wood flour to match color. To make it less messy, run a strip of masking tape down each side of the joint, defining the fillet area. Apply the thickened epoxy (peanut butter consistency), tool it to the desired radius (which should just reach the edge of the tape). Allow to begin hardening, pull the tape, then do any last-minute tooling to get a feather edge.

I think you'll be quite pleased with silica over the lumpy fibers. Good luck.

Ross

: Question: I am having trouble getting smooth fillets. If the epoxy is thin
: enough to lay smooth it runs and if it is thick enough to not run it is
: rough and hard to tool smooth. Does anyone have any tricks or ideas to
: make a smooth well formed fillet. Sanding after they are hard is not much
: of a solution... I've tried it.
: Background: I am building a 17' S & G Kayak and I am having trouble
: getting the fillets smooth and well shaped. The thicken epoxy clings to
: the tools( cotton filler in East System Epoxy) or if not so thick it won't
: stay in place on the inclined sides. Any comments would be appreciated.
: Thanks