Abstract: The invention relates to a downdraft paint booth having an overspray filtering system integral with the floor grates, and to the floor grate filters themselves. The grates have a load bearing frame portion having enclosed within it an integral or removable recyclable filter. The filter is preferably metallic and of a construction that will withstand baking in a high temperature oven to reduce captured overspray particles to an inert ash. Alternatively, the combination floor grate filters may be cleaned of paint residue by immersion in a suitable solvent or chemical bath. The floor grate filters will have 95-99% efficiency at removing airborne particulates. Secondary filters may be used after the combination floor grate filters to remove any final over-spray passing the filters. Typically, the floor grate fillers will go through five to ten cleaning cycles before he secondary filters would need replacement.

Abstract: A filter frame and media capable of withstanding repeated heating to high temperatures in an oxidizing environment, and a method of cleaning the same for indefinite use in a method of operating industrial paint booths. Progressive density, heat resistant, and preferably metal media paint booth filters are provided for replacement of existing filters in industrial paint booths. The filters are structurally resistant to cyclic heating to high temperature in an oxidizing bake-off oven where the paint residue accumulated on the filters is reduced to ash. After cooling, the ash is removed, and the filters returned to service, and the cycle is repeated. The filter comprises a frame section and a mesh media section which has a plurality of mesh portions. The mesh portions are preferably arranged in a series M.sub.1, M.sub.n-1, M.sub.n, wherein n is a positive integer of 4 or more, that are sized with the free face area A.sub.