The blue 3M Quick Release tape works well to mask both sides of the gap. Then pull the tape BEFORE the epoxy cures.

You could try to fill the gaps just before doing the sealer coat, but what happens is the unthickened epoxy from the sealer coat tends to liquify the thickened epoxy in the gaps and you'll get some bleed out (this is from experience). I think the tape is the best way to go.

As long as you don't have any scratches across the grain there is really no benefit to sanding any finer before the sealer coat.
: Greetings.

: 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