Koen - I think it’s a great idea to have a dedicated thread for nozzle designs, even if it leads to some double posting.
I just started experimenting with a charcoal gasifier for the first time a few weeks ago, and promptly melted two steel nozzles. They lasted less than 15 minutes each.
My current design is an alumina ceramic tube wrapped in a thin ceramic blanket, and stuffed into a steel nipple. The alumina tube extends beyond the steel nipple about 2 inches.
Only have about 40 minutes on this nozzle. So far, so good, although I might be able to discern a hairline crack starting to develop.
Will let you know how it holds up.
