On Monday, May 18, 2015 at 2:38:43 PM UTC-7, PBA wrote:
Back on topic...is there good material to protect the underbelly of a sailplane?
I would be interested in protecting the base of the wing spar opening on the fuselage. Years of assemblies have started to wear a groove and it's getting thin. Something Teflon Based? I see from a previous post, not an easy material to bond to something else.

The material for that is UHMW PE tape, available in various thicknesses and widths, with either rubber or acrylic adhesive. Common thickness ranges from about .005" to .020". Available from McMaster-Carr or Amazon etc.

Note that as you approach 10 mills, the tape starts getting more rigid and is suitable mostly for flatter surfaces. For lining the fuselage spar openings, you'll want .005" (or there'bouts, and acrylic adhesive).

UHMW PE is almost as slick as Teflon, but has much higher mechanical strength. Teflon, will slippery, is not nearly as wear resistant or useful as an anti-abrasion liner. For tough jobs, UHMW is best.

bumper
I probably have a dozen rolls of UHMW PE in various calibers in my hangar :d)