PTFE in Flame-Licker

[t_ottoboni]

Hi!

Is there anything wrong in using Teflon (PTFE) to make the piston and internal valve in Jan Ridders internal vale vacuum engine? I know that the max temperature for teflon is around 250oC or 480oF. Does the temperature inside the engine goes above this?

Thanks a lot!
Tarik

 

[GailInNM]

Tank,
There is no problem with the temperature degrading the PTFE, but it will work poorly as a piston.

The temperature rate of expansion is much higher than than metals. If the piston is fitted at room temperature, then as the engine warms up enough to run the piston will expand more than the cylinder and bind in the cylinder. If you cut the piston undersize to allow for this, then there is too much leakage at starting for the engine to run. There are some filled PTFE products that reduce this effect but not enough to make a good performing engine.

Gail in NM

 

[mklotz]

Also, before you start heating pieces of plastic, acquaint yourself with what gases might be so produced. I think some of them can produce some really nasty stuff. Check the MSDS sheets for the chosen material.