[Bellerophon]

When the fillet was made at Bristol it was over size both on the outside
that fits into the steel frame, and on the inside where the roof lining is
trapped between the wood and the aluminium finishing strip.
The method of fitting the wood frame which has two functions first to hold
the glass in position and secondly to form an attachment point for the roof
lining, is to use a spoke shave or similar tool to obtain a fit of the
wood in the frame. The inner side can then be formed using the aluminium
finishing strip as a gauge and allowing for the thickness of the roof lining.
When the car was made the window was sealed using a mixture of 50% Bostic C
and 50% Dum Dum, however there are modern materials now.
These wooden frames only fail when the seal gives way and lets in the
water, this can be detected by water finding its way into the boot, so if this
is the case act on it before you loose too much of the frame.
Hope this is of help, my regards,
Bellerophon