TIG Collet Body vs Gas Lens: Differences and Selection

TIG torches come with a number of interchangeable consumables, and the collet body is one of those. Even though they seem like insignificant pieces, the consumables in your torch can make a difference to the quality of your weld.

Each consumable can be changed: the back cap comes in different lengths, you can get clear cups to see the weld better, and you can swap your collet body out for a gas lens. But, what’s the difference between a collet body and a gas lens, and why would you swap?

Collet Body

A collet body is one of the standard consumables that make up the assembly of a TIG torch. They do two things at once: hold the electrode in place and allow the shielding gas to blow over the weld.

But just because they’re what comes standard in a TIG torch, does that mean they’re the best?

A conventional collet body distributes shielding gas through openings around the electrode. It is not a gas-purifying filter.

A standard collet body can give adequate shielding when correctly set up for the joint.

A gas lens is an alternative when more uniform gas flow or additional electrode extension is useful.

Gas Lens

A gas lens replaces the collet body in the assembly of a TIG torch (but not the collet itself!), so it does the same things for the most part. It holds the collet in place and distributes shielding gas over the weld.

However, unlike a collet body, rather than a few holes, a gas lens comes with a diffuser and a mesh screen (it looks like a mesh doughnut around the centre, where the electrode sits). The diffuser and mesh screen means that the gas is dispersed evenly across the weld pool in a laminar pattern, with way less turbulence.

Advantages of a Gas Lens

• More gas coverage
• Less turbulence in the gas
• Longer electrode extension is useful only while shielding remains adequate for the electrode and weld pool.
• The mesh helps straighten gas flow; it does not remove chemical contamination from the shielding gas.

Choose the setup for access, visibility and gas coverage. A gas lens is useful in many applications, but is not compulsory for a sound TIG weld.

Match the lens, collet, cup, insulator and back cap to the torch family as well as the electrode size.

Reference diagrams: UNIMIG. Original source attribution is retained.