Precision plastic
that behaves like metal.
Self-lubricating.

Delrin for: dimensional stability, low moisture sensitivity, precision gears, bearings under load, low-friction dry-running. Nylon for: higher strength when glass-filled, better impact resistance, lower cost, higher temperature service. A common heuristic: if the part needs to hold ±0.05 mm tolerance in varying humidity, use Delrin. If it needs 100 MPa strength and moderate tolerance, use nylon.

It depends. Homopolymer (DuPont Delrin) has slightly higher strength and stiffness but can develop internal porosity ("centerline porosity") in thick sections over 1 inch. Copolymer (Celcon/Ultraform) is more dimensionally stable in hot water/steam service and has no centerline porosity. For thick-section parts or hot water service, copolymer. For thin-section precision mechanical, homopolymer.

Gluing: Delrin is notoriously difficult to bond with adhesives. Surface preparation (plasma treatment, sulfuric acid etch) enables cyanoacrylate or epoxy bonding, but strength is modest. Welding: ultrasonic welding works. Hot-plate and vibration welding also possible. For Delrin assemblies, mechanical fasteners or press-fits are usually preferred over adhesives.

Delrin is attacked by strong acids (concentrated sulfuric, nitric, hydrochloric) and chlorine at elevated temperature. Swells in some ketones and aromatic solvents. Stable in most alcohols, hydrocarbons, dilute acids and bases, oils, fuels. For aggressive chemicals, specify PEEK or PTFE instead.

Yes — FDA-compliant Delrin grades (such as Delrin 100P NC010) meet FDA 21 CFR 177.2470 for food contact. Specify the food-grade variant explicitly when ordering for food processing applications. Most standard Delrin 150 and 500 grades are general-purpose and not automatically food-contact certified.