: If this stuff is what I think it is, could this be used to help mix with
: putty, glue or resin to help fill cracks and gaps in my cedar strips?

Randy, yes you can use it to mix with epoxy to fill cracks. It is very finely ground wood dust...don't go overboard filling cracks.....the epoxy will fill quite a bit by itself....and you are correct in your previous post about the difficulty of sanding the hardened epoxy spots on an otherwise uncoated surface......so put tape on both sides of the large cracks and fill them...be sure to scrap off any excess epoxy before it cures completely....the little cracks don't worry about....good luck