Here's a handy tool that works.......for puttying inside corners prior
to overlapping
with class fabric and resin.

Go to K-mart, Wall-mart or Target and buy
two cheap, meat cleaver-shaped Japanese
vegetable chopping knives. Grind the front face of each knife so it
forms
a right angle with the sharp edge of
the blade. Now grind a nice rounded
fillet shape onto the front corner of
each knife, so one knife has a slightly
wider radius than the other.

The small diameter knife is perfect
for applying epoxy putty to an inside
corner, making a nice smooth
inside-corner-shape in the putty. But doing so makes two long beads
of excess squeezeout putty next the nice
round inside corner you wanted.

The second knife, with the slightly wider radius on the front corner,
is
perfect for scraping off the squeezeout. Because the radius of the
rounded corner is wider on knife number two,
you don't even have to be careful. It won't screw up the inside
bead you just made, no matter what.

Works like a champ.
You can fillet out the inside chine corner of a boat in a 2-3 minutes
work,
with near perfect results.