Corporal Jones wrote:
That is the good thing about good quality silicon, it is flexible.
I have used it for donkeys years (well at least the last 30) to seal
vacuum pipes that start at atmospheric and pull down to 5mb, you can
visibly see the flexible pipe shrink and stretch at 15 cycles per min.
but the silicon holds the seal.
For this use I use "Wacker" or "GE RTV", the sheds sell inferior products

Thanks, Corporal, re. Wacker and GE RTV. Have looked them up on the web
and they would clearly suit my job well.

Eddy.