Things that make me say hmmmmm

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On a standard TIG machine with the gas solenoid in the machine and a tig torch of average length I would think between welds the hose from the solenoid to the torch tip would become filled with just straight air?   When you start up again wouldn't there be air hitting the weld or is that what pre-flow eliminates?  Do the torches have some kind of check valve near the tip?
Reply:No, but it takes a while for the argon to leak out.  That's what the purge is for, when you start up.
Reply:It's exactly what pre-flow is for.  To exit all the air the may have entered the gas line up to the solenoid in the machine.  It would be nice for tig torches to have a check valve to prevent the gas hose from dissipating the argon that fills it, but alas that is just wishful thinking. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:If your torch is a "V" (has a valve) you can turn off the gas when you stop welding. No reason why you can't have a solenoid and valve, just remember to open the valve before you start welding again.GravelThe difference between theory and practice is that in theory there is no difference.
Reply:Always give the pedal a little pop to get the gas flowing before you go start up your puddle, purges the line out and prevents you from having a bad start to your day.