Myles1970
Member
- Messages
- 900
- Location
- Monaghan, Ireland
Do you mean purging the gas line? I thought pre-flow was intended to shield the weld area?Pre flowing the gas is more something you do with a proper torch rather than one with the gas valve in the torch. With a proper torch MB15/25 etc the gas valve is usually in the machine and you'll have quite a length of pipe before the tip, so lots of room for contamination from air thats replaced the shielding gas in said pipe. With the valve in the torch there is only about 4 inches of air to contaminate which gets blasted out pretty much instantaneously when you press the trigger.