[Geoff Kingston]

I think perhaps using a bonding type material rather than a sealer may not be a good idea especially as the original mix was flexible.
I was very lucky to have an original wooden frame made by Bristol and bought many years ago and even luckier that Dave Ralls who has done some trimming work on my cars was able to make up a jig to reproduce them. Made in the same was as the original the only departure is that after realising that most of the adjustment, as they were made oversize originally,is on the inside of the frame is that Dave makes them in two pieces with a small number of the inside laminations separate to reduce the amount off work if the inner alloy frame is larger than average, I have four of those alloy trims here and none of them are the same size or shape though reassuringly all the frames are a snug fit in the surround in the body. If anyone needs his contact details please let me know.
Going back to the sealants there are a lot of choices on the market and perhaps asking one of my friends who used to have an ocean going trimaran might be an idea as there would have been sun movement and salt water thrown into the mix.