Dan,
Extruded window rubbers, after cut to length and fitted to your taste, glue them with Loctite "Black Max 380".
It is from the family of superglues so take care not to glue your fingers.
It is perfect for bonding rubber ends together. Very strong bond.
Can be had at most industrial supply stores that sell Loctite products.
Not all carry it in stock, it is easy to get though. After use, store in fridge, it will prolong the life of the remainder in tube.
Rick M.
