On Thu, 14 Feb 2008 00:59:26 -0600, Richard J Kinch wrote:

npwbill writes:

I'm using a 2" UHMW piston in a PVC cylinder and the wear seems to be
OK, but I really feel there's something better and probably "slicker"
against one another out there than what I'm using now

UHMW-PE is self-lubricating but the PVC may have filler that is
abrasive.

Teflon is pretty prohibitive for cost, ...

You can get bondable PTFE sheets to line things with for ultimate
lubricity at low cost.

Small Parts, Inc. has PTFE o-rings. Dunno what your price point is
between 'affordable' and 'prohibative', but a couple of them on a piston
will be cheaper than a whole piston.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html