I have had good success using a very dry filler immediately before glassing (no seal coat). The dry filler does not soak into the wood and does not effect the wet-out coats ability to soak into the wood. It does not seem to have the problem Michael mentioned of bleeding out afterwards.

I mix wood flour, cabosil and micro-spheres with a small amount of epoxy to make a filler that is very stiff and dry. I force this into the crack with a putty knife and scrape off the excess.

I then procede immediately to the glassing.

: I'm just about to apply some epoxy/wood dust putty to a few gaps on my strip
: boat. It's my second boat (first kayak) and I want to avoid a mistake I
: made on the first one. The wood surrounding the area to be filled with
: putty seems to absorb a very slight amount of the resin from the putty,
: enough to seal the wood. The problem is that when I go to do a sealer coat
: on the whole boat with less viscous/more thin resin, more of the stuff
: absorbs and I get a difference in color between the wood surrounding the
: patched area, and the rest of the boat. Does anyone have any suggestions
: besides be more careful and apply the putty only to the gaps?

: I have already sanded the boat with 80 grit and have taken off as much of the
: wood as I need to. My plan at this point is to putty, sand with 100, then
: with 120, then apply a sealer coat.

: Thanks in advance,

: Lars Durban