Straight answers to the questions people ask most when choosing and fitting TIG torch parts.
What is the difference between a collet and a collet body?
The collet is a small slotted sleeve that grips the tungsten electrode. The collet body is the larger part it sits in, which screws into the torch head and has holes that let the shielding gas flow around the tungsten towards the cup. When the back cap is tightened, the collet is pressed into the collet body and clamps the tungsten.
Both must match the diameter of the tungsten. A collet and body that do not match, or are worn, will not grip properly and can cause poor electrical contact.
What is a gas lens and how is it different from a standard collet body?
A standard collet body lets gas pass through a few holes, which can make the flow a bit turbulent. A gas lens body has a fine mesh or stack of screens that smooths the gas into a steady column. That gives better coverage, so you can often use a lower flow, and it lets the tungsten stick out further for a better view into tight joints.
Gas lens parts are a common upgrade for stainless steel, aluminium and awkward joints. They need clean, dry gas, because the mesh can clog.
How do I choose the right cup for my TIG torch?
Cups are made in ceramic (alumina), clear glass and other materials, and in a range of sizes and lengths. The size depends on the tungsten size, the current and the joint. A bigger cup covers a wider area with gas, but is bulkier and can block your view. A longer cup helps with reach but needs a suitable gas flow.
The cup must fit your torch series, and a gas lens usually takes a cup designed for it. Glass cups let you see the weld better, but they can crack with heat or knocks.
Why do my collets burn out or twist?
Collets burn and twist when the electrical contact is poor or the heat builds up. Common causes are a collet that does not match the tungsten size, a loose or worn collet body, a back cap not tightened properly, or running a torch beyond its current rating.
Check that the collet, body and tungsten sizes match, make sure everything is clean and tight, and consider a better fitting or higher-quality design if you weld at high current for long periods. Replace damaged parts, because a poor collet can overheat the torch head.
Will these parts fit my torch?
Not necessarily. Torch makers use their own part sizes and numbering, and parts that look alike can differ in thread, length or diameter. Do not assume that a part will fit just because it looks right or has a similar name.
Check the data plate or the manual for your own torch, which should give the model and a parts list. Match the thread, the tungsten size and the length of each part against it. If you are not sure, our team can help you identify what you need.
What does a long or short back cap do?
The back cap screws into the rear of the torch head and presses on the collet to clamp the tungsten. Standard back caps are long enough to take a full-length tungsten. Short back caps allow you to use a shorter tungsten and work in tighter spaces, or reach into places where a long torch will not go.
The back cap has an O-ring or seal that keeps air out and gas in, so check it for damage. Use the style designed for your torch series.