Make sure to drill stop holes at the ends of the cracks first.
I saw some high temp refractory paste online today while looking for materials to make v2 hog gaskets out of. But the paste was expensive over $100.00 for a pint.
Interesting. I'll check that out. I'd like to repair it with steel plate, but if I can't find a specific kit to do that, I may consider a product like the paste. I can build with wood, but I don't have the experience with metal repair. Thanks much!!