Delrin 100AF Plate, 13% PTFE Filled

Acetal homopolymer with 13 percent PTFE powder through it - a high-performance bearing and wear plate, and the direct alternative to the PTFE-FIBER filled grade. Same job, different filler form: powder rather than fiber, from a different mill, and usually at a lower price for the same thicknesses.

The two are worth comparing on your own part rather than on a datasheet. Powder disperses more evenly and tends to give a smoother machined finish; fiber reinforces as well as lubricating and holds up better under higher loads. Both run dry against metal. We stock the same seven thicknesses in each, so tell us the duty and we will quote both.

Specific gravity for shipping is 1.50, the published figure for the PTFE-filled homopolymer. One disclosure: we could not find a separately published density for this grade specifically. The rule of mixtures on 13 percent PTFE gives 1.49, so 1.50 is the conservative choice and errs heavy on freight rather than light. If an exact shipping weight matters, ask us and we will get the mill figure.

Where it goes: the same places as the fiber grade - bearings, bushings, wear strips, thrust washers, unlubricated gears and cams.

No food-contact claim is made on this grade, and that is not caution for its own sake. The FDA acetal sections clear the resin and a short list of adjuvants; the filler in this grade is not among them. Published compliance charts list the filled acetal grades as not FDA compliant. If you need a food-contact acetal, ask us about the unfilled or a purpose-built food grade and we will tell you what the certificate actually covers.

The warning worth more than any number on this page: CHLORINE ATTACKS ACETAL AT 3 TO 5 PPM. That is ordinary municipal tap water and ordinary sanitizing concentration. Acetal in a chlorinated circuit, a pool system or a sanitized wash-down line will craze and fail, and almost nobody prints this. Strong acids and strong bases attack it too, and the homopolymer's window is the narrower one. If chlorine is anywhere in the application, ask us before you machine it.

Machining notes. It is among the easiest engineering plastics to machine well and takes a genuinely fine finish - sharp tools, positive rake, generous chip clearance, coolant optional on light cuts. Thermal expansion is high for a plastic, so a part machined warm measures differently cold; let heavy sections normalize before the finishing cut. Homopolymer is the harder and more brittle of the two acetals, so inside corners want a radius.

Safety, and this is specific rather than boilerplate. Acetal evolves FORMALDEHYDE above 446F and also on contact with strong acids or strong bases. OSHA's permissible exposure limit is 0.75 ppm over eight hours with a 2 ppm short-term cap, and it is a sensitizer, so repeat exposure matters. Keep tools from overheating the cut, use local exhaust, and never let acetal swarf mix with PVC, because halogenated polymers can trigger sudden formaldehyde release from it. Ask us for the manufacturer's Safety Data Sheet and work to it rather than to this paragraph.

How this is sold: by the square foot, cut to the size you need. The mills supply plate in full sheets and we cut from them, so give us the dimensions and we will quote the cut piece rather than making you buy a whole sheet.