[PeterL]

I haven't touched a gun since Her Majesty no longer required me to do so some seventeen years ago and my knowledge of such things is limited, but it will have to be something itself flexible if you are not to store up more problems for later on. The materials natural tendancy to flex will remain whatever you do. I would suggest fixing a plastic brace to the inside surface with an epoxy rather than cyano. You could try welding plastic to plastic with a low heat soldering iron but you would most likely end up ruining the thing.