Propane burner made with 1″ pipe, 1-1/4″ to 1″ adapter, M10x80mm bolt, M10 nuts and large washer and 0.8mm mig welder nozzle. All found for cheap at the home improvement store. Tested with gas at 0.5bar (around 7psi). It can run a bigger flame by increasing pressure but I think like this is enough to heat a forge or furnace. I can adjust propane flow with pressure regulator between gas tank and burner.