Hi Todd,

Wood flour is fine, but will turn out a lot darker than the wood it came from, You can lighten it up to match your ply by adding some bakers flour (wheat flour). I mix up a batch, scoop it into a zip lock bag, snip the corner off and use this as an applicator. It's as easy as running a bead of silicon from a tube. Then I just run a gloved finger down the bead to smooth everything out.

Hope this helps,

Paul.