Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

That is an intersting approach.  It has potential.

But, JB Weld is not very flexible, it seems to be somewhat stiff and brittle in nature.  The boiler is thin, and will flex with pressure.  It seems that JB Weld is much more likely to leak than a rubber or silicone seal that would allow flex and expansion with heat..

Have you made that repair and had it work ok over time?