Posts Tagged ‘identification’

One of the most common questions the DIY community has is trying to figure out what type of plastic they have or need. Maybe you have an old part or sample and you forget what it is? Perhaps the two plastics people most want to differentiate between are acetal and UHMW (or other polyethylene). But they both come in white and black and they kind of look similar, so what to do? Well, if you’re familiar with the two plastics UHMW or HDPE will feel different: more waxy and lighter than the acetal which almost feels like more of a metal than anything.

There’s another way to identify polyethylene though as long as you can disfigure the sample. Take a sharp knife, such as a steak knife, and start scraping the plastic, give it some gusto with long strokes. If the plastic shaves off in curls then you have polyethylene. Acetal and other plastics will not do this, an example of polyethylene with this type of shaving is pictured here: