What is a Mill Finish? (with picture) - Info Bloom
If planning to apply a sealant or a silicone base adhesive to a mill finished piece of aluminum, the surface must first be wiped clean of any residue from the extrusion or rolling process. This residue will only be removed by wiping with a light chromate or a phosphate etching material. Simply wiping the reside off with a finger will result in the residue re-forming on the surface of the …