MRO Magazine

Make 'Em Last: Tips for selecting and maintaining TIG welding torches


Industry

August 23, 2010
By PEM Magazine

Having the right equipment for your maintenance and repair operation is critical to completing the job correctly and efficiently — and welding equipment is no exception. From the power source to the torch or gun and consumables, every piece of the welding system plays an important role.

Torch Maintenance Tips
Remember to conduct routine inspections and undertake some simple maintenance to make them last. Here are some helpful tips:

Tip 1: Use a woven nylon cable cover to protect hoses and cables from damage and to prevent high-frequency problems that may lead to premature failure.

Tip 2: Remove the collet and collet body periodically and wire-brush them to remove oxides. Doing so helps prevent an erratic arc and can extend its life.

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Tip 3: Check that all components in the TIG torch are tightened properly. Secure connections prevent problems with electrical conductivity that can damage the torch’s front-end parts.

Tip 4: Examine the nozzle for signs of wear, including distortion, cracking or blackening, as these problems can lead to poor shielding gas coverage. Replace nozzle if damage is evident.

Tip 5: Inspect for cracks in the handle by inserting a wooden dowel or your finger into the back end of the torch. Replace the handle if damaged in order to avoid shocks. Do not use tape to repair the handle!

Tip 6: Check the silicon rubber insulation surrounding the torch body for any cuts. Or if you have a phenolic torch body, inspect it for cracks. Replace if irregularities are found.

Tip 7: Looks for cracks or signs of deterioration on the insert, or O-ring, attached to the back cap. If needed, replace the O-ring to prevent aspiration as it can lead to weld defects.

Tip 8: Keep the threads connecting the back cap and torch body clean, look for any signs of wear on the threads and replace as necessary.

Consider the tungsten inert gas (TIG) torch in a TIG welding system, responsible for carrying and directing the welding current to the weld joint. Without it, the welding process cannot be completed. For that reason, selecting the right TIG torch for your application and maintaining it properly is key to making this equipment function properly and last longer.

1. Consider the two options of hose and cables: vinyl or rubber. Vinyl is less expensive and is practical if you have light-duty TIG welding repairs. Rubber hoses and cables, especially braided ones, tend to last longer, offer higher performance, provide good heat resistance, resist kinking and maintain flexibility and durability in cold environments.

2. Select the correct torch body. If the power source you are using does not have a gas solenoid, choose a torch body that includes a gas valve control, as it can be turned on and off as needed to control your shielding gas usage. Also, look for a torch body that has good insulation, which helps protect against damage and can protect against high frequency leakage. Most TIG torch bodies feature silicon rubber insulation, including the high-dielectric type. High-dielectric silicon rubber withstands higher voltages without breaking down, again lengthening the life of the TIG torch. Silicon-rubber-insulated torch bodies are also more resilient than hard phenolic torch bodies (another torch body option) to resist cracking if dropped.

3. Ensure good arc stability with a torch body with heavy copper construction, along with highly conductive copper components, such as collets and collet bodies. As a rule, collets and collet bodies composed of a tellurium-copper alloy offer the best conductivity and are also more resistant to heat than standard copper ones. They also resist twisting or elongating to hold the tungsten more securely, which in turn ensures a steady arc and good weld quality.

4. Consider the backcap, responsible for placing pressure to the back end of the collet to force it against the collet body while also holding the tungsten in place and sealing the torch head from the atmosphere. A good rule of thumb is to select a backcap that is composed of compounds that fit the amperage requirements of your application. For more demanding applications, choose a backcap with a higher thermal resistance. Also, be certain to choose the proper length backcap for the job; use a shorter backcap for applications with limited joint access and a longer one when access is not an issue.

5. Consider adding a gas lens if you are making TIG welding repairs on a joint with limited access or if you require greater shielding gas coverage. Gas lenses replace the collet body in the torch and are designed to increase shielding gas coverage and reduce gas turbulence to improve weld quality.

6. Select the correct nozzle. For low to medium-amperage welding repairs, alumina oxide nozzles are a good choice. To gain the best performance and a longer life span, look for ones with no less than 95-percent alumina content. Conversely, lava nozzles offer good crack resistance for medium to high-amperage applications.

Take time to select a durable torch and components with features that get the job done right and minimize downtime.


Joshua Sprinkle is a regional manager with Weldcraft. For more information, visit www.weldcraft.com.