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Identifying plastics?

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WCraig

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Hi:

I got a box lot cheaply at an auction filled with what appears to be 4-5 types of plastics. How could I figure out better what I have? Couple of pictures follow:

IMG_2956.JPG IMG_2957.JPG

I have a little project where I think a couple of small pieces of UHMW would be ideal (low friction, easy machining). Would the whiter pieces in the middle of the second picture possibly be UHMW?

I wondered if I calculated weight per volume if that would help?

Thanks for any help,

Craig
 

RJSakowski

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MatWeb is a good source for information on various plastics. You will have a difficult time distinguishing various types of polyethylene by density alone.
I usually do a burn test as a first pass. Different plastics smell differently when I heat them with a soldering iron. Polyethylene and polypropylene have a candle wax odor to them. Nylon has a very distinctive odor, as does Delrin(acrylic). Acetone will attack PVC and ABS but not polypropylene, polyethylene, Nylon, or Delrin. Teflon os another fairly common plastic but there are several formulations. Teflon will resist the burn test.ro aq large extent. Hardness is another test that can help identify plastics.

To complicate matters, there are numerous plastic alloys as well as some exotic engineering plastics like Ultem and PEEK.

https://modernplastics.com/wp-content/uploads/2015/03/how-to-identify-plastics.pdf
 

WCraig

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I'll dig out a soldering gun and try those tests.
 
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