I dug up this out of my archives.

When I built my strip canoe I used Durham’s Water Putty as instructed in Gil Gilpatrick’s book “Building a Strip Canoe”. I discovered it is a very pale yellow color and it did not match the dark cedar I used to strip the canoe. So I used aniline dyes to color it which worked quite well. Aniline dyes are a water-soluble powdered dye available at wood working supply houses. It took very little dye to color the putty, 1/8 teaspoon per 4 tablespoons of putty. Dissolve the dye in a little water before adding it to the putty or color streaks will appear. I smeared the whole hull with the putty using a green scrub pad and then after it set I sanded back down to the wood. It filled every staple hole but it took a lot of sanding to get back down to the wood. Contractor supply houses carry Durham’s. It comes in a round red fiberboard can with a pry-off lid.

Most builders use epoxy and wood flour for filler. A lighter color of wood has to be added to your sanding dust or the filler will be darker than your strips.

Another method is to use thickened epoxy. Mix a little less than half the hardener with resin and let it set over night to gel. Add the balance of the hardener, mix and use it for the putty. It will take some experimenting to get the best proportion of hardener to resin to make the gel. Using thickened epoxy will create clear windows at the gaps.

And some builders just buy colored fillers. Don’t use oil-based putty. Oil interferes with the wood to epoxy bond.