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. System Three wood flour, a very fine, filtered, wood by-product is an excellent all around filler for creating glues and structural fillers. Wood flour forms a coarser "epoxy" than silica thickener. Phenolic microballoons are hollow, purple-brown phenolic spheres that are a great low cost, low density filler (ideal for areas requiring sanding). Wood fFlour and/or silica thickener may be blended with pPhenolic microballoons to prevent sagging.

• Excellent for creating wood glue
• Forms a coarser "epoxy" than silica thickener
• A fine sawdust additive with no lumps
• A fibrous filler
• Excellent all around filler