Density worked. Took some measurements, did some weighing .. all my materials came out to the expected products within about 1% error.
Lots of UHMW as expected, some PTFE, and couple of 1/2" thick 4" wide, 18" long sheets of Delrin, and one nice 12" x 6" x 1/2" sheet of Ketron Peek. Surprised, about $1000 worth of exotic plastics (at McMaster prices) .... most of that stuff came from people that donated it cause they know I make a lot of projects, or scrap that I picked up at auctions.
Already laminated the density chart to go in my shop info binder
Shame the Delrin is in 1/2" sheets, would be a pain to machine into bushing.