Practical answers on torch switches, cable covers, stick-out gauges, back caps and gas or water adaptors for small TIG torches.
How far should the tungsten stick out of the gas cup?
There is no single figure. How far the tungsten should stick out of the gas cup depends on the joint, the cup size and whether a gas lens is fitted, so follow the torch maker's guidance for your torch.
Flat butt joints generally need less, so the cup stays close and the shielding gas covers the pool well. T-joints and fillets often need a little more, because a close arc is needed to reach the root without the cup bumping the work. More stick-out reduces gas cover, particularly without a gas lens, so use the shortest extension that gives the access you need and increase gas protection or use a gas lens if you must extend further.
What does a gas lens do compared with a standard collet body?
A standard collet body releases the shielding gas through a few small holes, which can create turbulence and patchy cover. A gas lens replaces it and passes the gas through fine mesh screens, giving a smoother, more even flow over the arc.
Because the cover is better, a gas lens usually lets you extend the tungsten further for access and visibility, which helps in tight corners and on materials such as stainless steel where clean shielding matters. It still uses a standard collet, needs a cup made for it, and the parts must match the torch and the electrode diameter.
Why fit a cover over the torch cable and hoses?
A water-cooled torch has several separate lines running back to the machine, and an air-cooled one has a cable and gas hose. They are easily damaged by abrasion and sharp objects as they are dragged around the workshop, and by spatter. A cover protects them from wear and bundles the lines so they are less likely to tangle.
It also makes the lead easier to handle. A cover does not replace regular inspection, so still check the cable and hoses underneath for damage, kinks or wear before use.
What is the difference between 2T and 4T when using a torch switch?
These are trigger modes set on the welding machine. In 2T, pressing the switch starts the arc and releasing it stops the arc, so you hold the switch for the whole weld. In 4T, you press to start the gas flow, release to ignite the arc, press again to end the weld, and release to finish the post-gas.
4T suits longer welds because you do not hold the switch down, while 2T is simple and suits tacks and short welds. The exact behaviour, including slope and start current, varies by machine, so check the machine manual.
How do I check a torch gas hose and fittings for leaks?
A gas leak wastes shielding gas and can draw air into the stream, which may cause porosity in the weld. Start by making sure all torch fittings are tight and looking over the hoses for cracks or damage.
If you cannot find the leak, a leak-detection fluid recommended for your gas equipment, applied to the hose and fittings, will show bubbles where gas escapes. Tighten or replace the faulty part, then rinse and dry. HSE guidance for gas equipment also advises leak testing whenever connections are made or a leak is suspected. Replace damaged hose rather than patching it.
What daily checks should I make on the torch cable, switch lead and connectors?
HSE guidance says the welder is responsible for daily equipment checks and for reporting defects. Look at the insulation on the welding cables, plugs and the torch itself, and make sure connectors are clean, undamaged and correctly rated for the current.
That includes the torch switch cable and any remote lead. HSE notes that the shock risk with TIG is much lower than with stick welding because the current is switched by the trigger or foot control, but it is not zero. Do not use damaged or taped-up leads; have them replaced by a competent person.