Wood Flour Wood Filler
Wood Flour, a fine sawdust that has been filtered so that there are no lumps, is excellent for creating wood glue and structural fillers and fillets. It is a fibrous filler that is also thixotropic. To make a smoother fillet, some users add a small amount of Silica Thickener.
Alternatively use SilverTip EZ-Fillet for ease-of-use.