Sole fillets -- new recipe

No, this post is not about how to cook up the catch from your latest fishing trip -- it's about the boat again.  

After letting the epoxy cure from gluing down the cockpit sole (floor) I removed all the clamps and put a fillet of thickened epoxy around the edges.

I was able to reach over the edge of the hull from outside the boat to do the area between B3 and B4 shown below, but the area shown above was done from inside. Working on hands and knees does slow down the process.  I ended up doing this fillet in two sessions.

This was the nicest fillet I've done to date.  I did sand it a bit to remove a couple high spots, but otherwise would not have had to bother.  

This great result is due to using a new recipe for thickening the mix.  In the past I have used wood flour alone, wood flour with a little silica, and West Systems filleting blend #405.  All those options produced good strong fillets with a fairly rough surface.  The wood flour closely matches the plywood in color, and the #405 is much darker in color.

For these fillets, I made a mix of 2 parts silica, 2 parts microballoons, and 1 part West Systems #404 high density filler.  It takes quite a bit to thicken up the epoxy (about  2+ heaping plastic teaspoons-full for each pump of resin), but goes on nice and produces a smooth fillet that seems quite strong, and yet is fairly easy to sand.  

The fillet on the left is the new one, and the one on the right was West Systems #405 filleting mixture, which I then had to fair with a microballoons fairing mix because it was too rough.  I then scraped/sanded the fairing mixture smooth.

Bottom line is that the new recipe is highly recommended!