: I taped my first attempt at an epoxy fillet and it proved more
: trouble than it was worth. Since the idea is to have the fillet
: taper out to zero, the tape can leave an edge when removed.
: Also, it needs to be removed while the material is wet or
: removing the final bits of tape can be difficult.
: Lately, I've been mixing a small batch of very thick epoxy (wood
: dough for brown, talc for milky white) and forcing the mix into
: a plastic syringe with a small flat stick. Then I snip the
: opening to about 1/8" and use it like a caulk gun. Slow
: steady pressure is the key to a nice even bead and you can do a
: final shaping with your gloved finger. The syringe just gets the
: mix in the corner without a lot of fussing. They are available
: at my Ace Hardware and possibly a drug store.

For wider fillets, you can put your thickened epoxy into a Ziploc sandwich bag (or similar), work the epoxy into one corner, and then snip the corner with scissors.
If you have ever used a baker's cake decorating bag, you will know the rest of the technique - just fold and squeeze.
For filling the bag (as in baking) put the empty bag into a coffee cup or similar container, and fold the edge over the rim. Then transfer the epoxy to the bag.

Like Ian, I've tried the tape idea and it never saved me much trouble.
A curved stick/spatula for forming the fillet (for wide thin fillets like a S&G keel-line, I just use a Bondo spreader curved in my hand) gives a uniform-looking fillet.

For cleaning up the edges, I make a couple of wood 'chisels' (piece of wood strip with bevel cut on the end with a sharp (steel) chisel. They do a great job of scooping up excess epoxy (or glue). That trick was one I learned from Sergei deJonge -cleaning up glue from the sides of guitar bridges, etc without scratching the surface.