Teflon rod as piston material?

[davesisk]

I've seen Telfon (PTFE) mentioned several times as piston ring material...how about Teflon rod for the actual piston material? Here's a link to a supplier:

http://www.onlinemetals.com/merchant.cf ... op_cat=181

I looked up the properties...looks like Teflon has a max working temp of 260 degrees C / 500 degrees F.

Thoughts?

Dave

[Chriske]

I think it's not workable because of the expansion, caused by the engine's heat.
Never tested it myself...
Other thoughts....?

Chris

[Ian S C]

If you'v ever pulled a car shock absorber to bits (great resource of parts for engines)you may find a plastic piston ring, some have cast iron rings, with some teflon sheet about 1mm thick, make a strip the width required and say 6mm longer than the circumference, then either cut the end diagonally,or make a stepped end, leave a little gap lengthwise to allow expansion. An aluminium piston, with a Teflon ring, or maybe two would be OK, Aluminium on its own has too high friction (got to get rid of as much as pos). Ian S C