Delrin is a plastic product produced by DuPont, a large multinational company founded in 1802. Delrin is the trade name for acetal resin, which is part of the polyoxymethylene (POM) family of polymer thermoplastics. Delrin, in particular, is known for its stiffness, low friction surfaces and impact resistance. Other characteristics include ultraviolet radiation (UV) resistance, chemical resistance and physical stability. In many applications, Delrin and other POM materials are stronger than other plastics, and can often approach metals in terms of strength. With these properties, Delrin may represent a challenge if you wish to polish the surface.
Select a number of different sandpapers with very fine grits, at least 1,000 grit or finer.
Wet-sand the surface with a belt or disc sander. Start with the coarsest grit paper and work your way to finer and finer grit paper. This results in a surface largely without any scratches and should be quite smooth.
Rinse the Delrin surface with an appropriate solvent to remove any residue.
Buff the Delrin surface, once dry, with an electric buffer. Do not put too much pressure on the Delrin object during this stage.
Wipe the surface with a very fine cloth to remove any smudges or debris. Your Delrin object is now at a very high gloss level.
In high UV environments, Delrin can have a layer of chalk deposit over time. This chalk can be removed by wiping with a clean cloth, but only during early stages of deposition. If the chalk is left for too long, it is difficult to remove. A variety of acetal polishing kits and solutions are available from different companies. In some cases, general plastic polish may work in conjunction with the polishing procedure.
Never flame-polish Delrin, as this method is not effective and constitutes a workplace hazard.