This is easier than it looks, and is it best to practice on a wrecked burner to gain confidence. This was done on an Coleman burner, where trying to remove the broken nipple as in Part 1 proved impossible. Cut off the two tubes containing the nipple seat with a hacksaw. Do NOT clean up the cut surfaces. The photo below shows the results of trying to remove the broken nipple threads on this burner using the technique outlined in Part 1. First drill out the old nipple using a 4mm drill, then re-thread with a 4.5mm tap (0.5mm pitch). Test fit and then remove a normal size nipple Flux and 'tin' the two cut surfaces (Easyflo flux, Silver Flo 55 braze) Flux the un-tinned cut surfaces and fit the burner together again. when you are happy with the alignment, wedge the pieces together and then reheat until the braze melts all around the joints, adding more braze rod if necessary. Clean up the joints and leak test underwater. (I fit a blank jet, and use a bicycle pump connected to the threaded end of the burner). Refit the jet, refit the burner to the stove and test. IMHO, this is a much easier repair than Part 1.