[blamazon]

In that case I think you want something that will 'vulcanize' with the material in the gasket, rather than being adhered... I don't know if that's feasible for your exact material but I know there are methods of rubber patching that are more akin to welding than glueing.

[vfinn]

Yes, something like that crossed my mind also, but it could be that it's not feasible in small diy work. Have to check.