Consider a TPU window for your convertible

February 1, 2012 | By Richard Prince


I have a 1966 Ambassador convertible with the original top and Plexiglas rear window. The top has some tears in it and I would like to replace it. My upholstery guy says he can make up the material for the top, which has an exterior grain like a vinyl top over canvas. The big problem is that I can’t find anyone who can attach the Plexiglas rear window into some top material so I can continue to use it instead of the typical plastic rear window that yellows over time.


I don’t know exactly how the Plexiglas window that’s in your old top is held to the top but even so I can’t think of any reason why it can’t be held in the new top the same way it’s held in the old one.

You may be able to use a product called IPS Weld-On to glue the Plexiglas window to the top. This is a two-part acrylic monomer-based glue that forms extremely strong bonds. Another option is to go with a new plastic back window made from thermoplastic polyurethane (TPU) rather than the traditional polyvinyl chloride (PVC).

The first production convertible to use a type of TPU for a convertible rear window was the BMW Z8. Other OEMs and betterquality aftermarket tops have since begun to use TPU rear windows as well. Compared with PVC, TPU won’t scratch as easily, is more resistant to discoloration, and won’t become brittle as quickly because of plasticizers leaching out.

(Editor’s note: That’s Ken’s Ambassador at the top of the next page.)