Practical answers on choosing, setting up and looking after an argon regulator for TIG welding.
What argon flow rate should I set for TIG welding?
There is no single figure. Maker guidance links flow to the welding current and the size of the gas nozzle, so start from the torch or machine maker's chart for your set-up. Smaller nozzles and lower currents need less; larger nozzles and higher currents need more.
Larger gas lens cups can need more again, so follow the torch maker's data where it exists. Run a test weld and adjust. If you are unsure, our team can help you match a regulator range to your torch and work.
Is more gas always better for TIG shielding?
No. Too much flow causes turbulence, which can pull air into the gas stream and contaminate the weld, so turning the flow up is not a cure for poor shielding. Too little flow leaves the weld exposed, which often shows as a dull bead, small holes or crater-like pits, or blue, purple or straw discolouration on stainless steel.
Set the flow for your nozzle size and current, then check for draughts and leaks before changing it again.
Is there a danger from the argon itself when welding?
Yes. Argon is colourless and odourless and is heavier than air, so it can collect in tanks, pits and other low-lying areas and displace the oxygen people need to breathe. HSE says an atmosphere with no oxygen causes loss of consciousness in a matter of seconds, with little warning, and people trying to rescue a colleague often get into difficulties themselves.
HSE also advises that safe systems of work should not rely on a heavy gas staying low, because air movement can mix it. Be especially careful with leaks from hoses, regulators or torches inside tanks and other confined spaces. Make sure there is adequate ventilation, and follow your risk assessment and the HSE guidance on asphyxiation hazards in welding.
Why are my welds contaminated even though the gas is on?
The usual causes are too little flow, too much flow causing turbulence, draughts, and air being drawn in through a leaking joint or damaged hose. Argon also settles in corners, so the flow needed can vary with the joint and with the shelter around it.
Block any breeze, keep the torch over the end of the weld until the gas stops, check every joint between cylinder and torch for leaks, and confirm the flow at the nozzle. Check the consumables and the cleanliness of the metal too, as these also cause porosity.
How accurate is the flow reading at the torch?
The reading at the regulator is a guide rather than a guarantee of what leaves the nozzle. Makers of nozzle-end flow testers note that the actual flow at the torch can differ from the setting, particularly with long gas hoses.
If consistent shielding matters, a flow test device fitted at the nozzle shows the real flow. If it reads much lower than the regulator setting, check for a leak, a kink or a blockage between the regulator and the torch, and follow the torch maker's guidance.
How do I open and shut down the regulator safely?
Check the regulator is the right one for the gas, that its inlet and threads are undamaged and clean, and that the cylinder is secured upright. Wind the adjuster off before opening the cylinder valve. Do not stand directly in front of or behind the regulator, open the valve slowly until gas starts to flow in, then open it fully.
When you finish, close the cylinder valve and let the pressure drain until both gauges read zero, then wind the adjuster off. Never remove a regulator while either gauge shows pressure. Keep the cylinder valve closed whenever the regulator is not in use.