I believe the general consensus I've seen is that JBW works fine in moderation, just not around the fire box. I was going to use it once and searched here and other places heartily, but ended up having a friend weld it. There's another kind rated to a much higher temp designed for automotive applications but the name escapes me. I'll post back if I can find it.....
Edit: CarGo ThermoSteel, rated to 2400 degrees vs JBW good to intermittent 550 degrees.
Kettleheads Anonymous Charter Member