A couple of things. Coefficient of thermal expansion will be important as
well as chemical resistance of Delrin to the hydraulic fluid. The modulus
of the Delrin is rather low for this purpose so you might want to look at
fiber reinforced, either glass or carbon, for modulus and also reduced swell
of the polymer which will better retain properties. Check out
www.mcmaster.com under raw material plastics for more information. I would
also consider the carbon filled PEEK as an alternative, more expensive but
also much more metal like in it's strength and properties, especially high
temperature.
Bill King
Formerly of E.I. DuPont De Nemours, Inc. manufacturer of Delrin Acetal
Resin. Presently joint ventured with DuPont Dow Elastomers, LLC.
On Mon, 18 Jun 2001 20:06:19 -0400, Paul Tegler wrote:
> This was/is a brand new slave cyl on the Midget...
> on spanking new rebuilt ribcase from Ted S.
> Less than a year old... maybe 500 miles tops....
> and it leaks badly.
>
> Upon inspection I see the inner walls badly scored
> and the piston inner end all scratched up.
> seal is fine.
> This is RIDICULOUS!
>
> QUESTION:
> Has anyone ever considered making a piston
> out of nylon or Delrin?
> Seems like it would be fairly easy to lathe one up
> that couldn't scratch the inner cyl.
>
> anybody prepared to make up a batch? interested in one?
>
>
> Paul Tegler ptegler@cablespeed.com
> www.teglerizer.com
>
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