[TheForge] Propane burners

[Shannell]

I was watching one of my UMBA videos and a guys was doing a propane forge
talk. He mentioned using a slight reduction in pipe diameter as the burner
flare enters the forge. So you have your 1:12 flare with the last 1-2mm
necking down. This is a 1992 or so tape, Ive never heard of using this mod
on these Reil type burners before, it helped combustion and prevented any
blowback by increasing velocity, Im thinking of maching up a small ring and
pressing it into the end of the flare, anyone else tried this ??