Paul,
  I found a place called SCI Laboratory Specialties (
  http://www.scicominc.com/teflon_sheet_stock.htm) that has 3/8" x 12 x 24
  teflon sheet for $134.  Not a great price, but beats McMaster-Carr's price
  by $40.  Maybe I can sell two strips of it to some others on the list for
  their slide throttles.  Everything else needed I can buy locally.

  Mark


 The important feature of the McMaster Carr sheets is the finely finished
 surface.
 I don't see any reference to finish quality, and it is extremely important.
 If they can match the finish for that price, I'll be happy to split one
 with
 you.
 Craig Smith


 Paul I googled high temp plastic and found

www.professionalplastics.com


which had pricing on plastics and machinable ceramics ( like the
westinghouse ceram air valves) and 1600 degree service temp is absurdly
expensive. They do have  a reasonable price on teflon. 3/8 X 12 X 24 is
$149.49 and they also have down to .031 thickness , have tried to attach
their advice on bonding teflon to other materials, remember this is a
non-stick material once used on cookwear. It envolves etching. this site has
mechanical properties  on pages of materials with online pricing.

george grimes


Teflon PTFE - Etched
Etched PTFE Teflon
Teflon PTFE is an amazing non-stick material, but what about when you
need to glue it to the suface of another material ? In order to bond
standard PTFE to another surface such as stainless steel, a process
called "etching" is required. Typical applications would include the
lining of chemical process tanks or other equipment used in caustic
environments. When bonding is needed, sodium ammonia etching is usually
the most economical answer. This process uses of a mixture of sodium
and ammonia that is formulated to create a bondable surface both quickly
and efficiently. Sodium/ammonia etching service complies with all
applicable commercial, military & federal specifications for the
surface treatment of all fluoropolymers including:
PTFE (Teflon), PFA, FEP, ETFE, PCTFE, PVDF, PVF, & ECTFE.
# From microchips to full size rolls, fluoropolymers of any shape
or complexity, including tape, sheet, tubing, molded shapes &
machined parts of any configuration can be etched & bonded. This
treatment can be accomplished on one or more surfaces, or
selectively within close tolerances. Note: Etched surfaces
will discolor to a grown appearance.
May be Etched on One Side (EOS)(Standard) or Two Sides (E2S)

http://www.whitetrout.net/Chuck/Teflon/teflon.htm