crb wrote:
I recently invested in a new Portaflame MAPP/Oxygen gas welder.
Results to date have been encouraging, and I am slowly improving my
technique. The only problem I have is that on shutting down, by
closing the torch controls for the MAPP and the oxygen a little at a
time in turn, I always end up with a loud and unsettling high-pitched
POP as the flame extinguishes. Can anyone give guidance on why this is
happening, and whether it is likely to cause damage/injury?
TIA.

CRB

=================
BOC used to supply a welding guide (Publication TC 1430) with their
'PortaPak' welding equipment.

The lighting up procedure specified in the guide is, acetylene on first
adjusted 'until the flame just ceases to smoke'. Then slowly feed in
oxygen 'until the white cone of the flame is sharply defined with the
merest trace of acetylene haze.'

Shutting down is the reverse - shut off the acetylene completely and
then shut off the oxygen.

These were the instructions supplied about 30 years ago and as far as I
know they're still the same today.

Just in case nobody else has told you - don't use any oil on the gauges
/ threads etc. It can be verydangerous.

Cic.