Originally Posted by skier219
I think this primarily affects skis with a metal layer *near the base* (normally right under the ptex). With heat, it expands and lengthens. Being near the bottom of the ski, it ends up curling the ski opposite to the camber.
Interesting theory. Have a look at some actual numbers:http://www.engineeringtoolbox.com/li...ents-d_95.html
We notice the TCOE for
polyethylene - 72 EE-6 in/in*(degF)
ABS - 55 EE-6 in/in*(degF)
aluminum - 12 EE-6 in/in*(degF)
epoxy - 10 EE-6 in/in*(degF)
wood (oak) - 3 EE-6 in/in* (degF)
So, your theory could be fairly correct for the case of Aluminum/oak core mismatch. The ski would be build as a base(matching layer)metal(epoxy)wood.
If the core is some sort of (non-epoxy, non-crosslink) plastic foam, the expansion of a uniformly heated ski with metal near the base would go the other way (making more camber).
|I imagine that if you could heat the upper surface of a ski with a metal topsheet, it would curl the opposite way. Cool stuff.
I'm surprised Phil hasn't tried this yet with FMJ Volants. Oh, wait, steel's pretty low on the list. Well, if he gets some Dynamics or Atomics with the magnesium topsheet it could work.
I'm getting several interesting thoughts from this thread.
One of them is that maybe we should sinter PE into bases with some sort of fiber reinforcement in the bases (steel whisker?) running along the bases. I vaguely remember something like this being done somewhen but can't remember where.
The other thought is that the PE number may not be for HDPE, which might conceivably be lower, but I am not happy about the thought of putting PE into 'cutting board' binding lifters anymore, not without metal backing sheets.