Hi, im planing on building a small pneumatic piston motor for a water mixer, and was considering making it out of UHMW, mainly for some fun and experiance with the material.

And I was wondering just how likey is a UHMW piston to surive a long time unlubed in a UHMW cylinder if speeds are not excessive?
Or maybe I should do something like a stainless steel or aluminum block and a UHMW piston that gets replaced?