On Wed, 03 Sep 2003 13:03:03 -0500, "Matthew P. Cummings"
wrote:



I agree it's odd, and I won't be doing as the volunteer at the EAA welding
forum suggested because everything he said flies in the face of what the
rest of the world is doing. He was the guy who said to crack the valves.
I don't have an opinion one way or another on it, but the other guy said
to not crack it at all, and by that he meant a quick open and shutting of
the valve. He claimed that the Acetylene might blow up if you crack it
and the other problem was you released that gas in the shop you are going
to weld in. I can't disagree with that however.

Acettlene goes unstable when the pressure goes above something like
15? psi undisolved. It is stored disolved in Acetone. Cracking the
valve gently, and closing it gently, will NOT get free acetylene
anywhere close to the critical point, and will make sure you do not
get dirt into the regulator, which CAN cause the reg to stop
regulating, and put free acetylene over the critical pressure.

How much gas are you going to release?? The average welder likely
releases as much every time he lights his torch.