I bought a used 18.5 WSM that had a bad chip in the lid.
Looked like a lawnmower threw a stone at it and made a direct hit, even tearing the cover fabric slightly.
I read everything that I could find on porcelain repair and nothing really sounded very promising.
Heat range was the deal-breaker.
I finally saw where one guy used High Heat JB Weld for a filler so I thought that I would give that a go.
It's supposed to be good for 500F and that's well above where I will operate the WSM.
The Damage (about a 2" in diameter)
Had to bang out the dent first....used a 16 oz hammer and piece of 1x (3/4" wood) and carefully worked it out.
The Kit
Wet Sand 220/320 (JB is hard...do not apply it heavily)
The blue tape helped to keep my sanding "inbounds"
Ready for Paint (used 4/0 steel wool to clean off JB at perimeter)
Paint Shield ....elevated about 1/2"-5/8" to control paint feather....this worked...better than spraying freehand and very likely enlarging the repair area.
The Result (Rustoleum Engine Enamel 500F High Gloss Black)
After 3 applications of JB and lots of sanding, it's much better than looking at that battle damage, not perfect but not bad.
Did some edge touch up while I was mobilized