System Three Wood Flour, 1 Quart is a finely filtered sawdust designed to be of lumps, making it an i material for crafting wood glue, structural fillers, and fillets. This fibrous filler is thixotropic, meaning it becomes fluid when shaken, allowing for easy mixing and application. For an even smoother fillet, some users enhance it by adding a small amount of Silica Thickener. Each quart of Wood Flour can be combined with one quart of mixed epoxy and hardener to create approximately 1-1/4 quarts of a non-sagging, firm paste. Proudly made in the USA.