Backcaps are composed of an assortment of phenolic compounds which have varying degrees of heat resistance. Select a backcap that is composed of compounds that fit the amperage requirements of the application. For example, if the GTAW torch is used for general-duty applications, a backcap made of a low-temperature phenolic compound will suffice. A backcap with a higher thermal resistance should be selected for more demanding applications.
If greater shielding gas coverage is required for the GTAW application, or joint access is limited, you should add a gas lens to the GTAW torch. Select a gas lens comprised of a durable porous media (as opposed to multiple thin screens). These are more expensive — but they last longer and provide improved gas coverage while reducing unnecessary downtime.
Selecting the right nozzle for the application is also an important factor. Lava nozzles offer good crack resistance for medium-amperage applications, while silicon nitrate nozzles are suited for high-duty cycle GTAW applications that are also higher-amperage. Both are more expensive than alumina oxide nozzles, which are appropriate for low amperage applications, but they better resist cracking and melting.
Beyond the components
Components aside, you’ll also need to determine whether an air- or water-cooled GTAW torch is best. As a rule, an air-cooled torch is a good option for lower amperage applications (under 200 amps) and a water-cooled torch would be used for applications requiring more than 200 amps.
Air-cooled torches are heavier, as they rely on the surrounding air to cool them. Select one with a comfortable handle; it will help make the GTAW torch easier to maneuver. Consider where the welding will take place, too. Outdoor applications lend themselves to the more portable air-cooled GTAW torch, whereas shop applications can better accommodate a water-cooled torch and its accompanying water cooler.
Also, there are flexible necks available for most GTAW torches. These can be ordered factory-direct from most GTAW torch manufacturers and should be considered when you have particularly tight joints to weld or for welding in awkward positions.
Some torch body styles feature a modular design, which allows not only a flexible neck to be added, but also different head angles. These types of modular GTAW torches work well for complex joints and/or for applications with a variety of different angles that need to be reached. They can also help lower costs by allowing you to customize a single GTAW torch according to application, instead of having to buy a different torch for each application.
Remember, a GTAW torch, no matter the application, plays an important part in the overall welding process. Take care to select one that meets your needs and that complements your power source. It will save time, money, and a lot of headaches.
Jack Fulcer is product and marketing manager at Weldcraft, (800) 752-7620, www.weldcraft.com.
10 Easy Tips for Maintaining Your GTAW Torch
Once you’ve chosen the most appropriate GTAW torch and components for your application, routine inspections and some simple maintenance can help make them last.
1. Use a woven nylon cable cover with a plastic zipper to protect hoses and cables from cuts caused by dragging, and to help avoid high frequency problems that can lead to torch damage.
2. Periodically remove the collet and collet body and wire brush them to remove oxides that can lead to an erratic arc and shorten consumable life.
3. Make sure all threads on connecting points of the torch are tightened properly to prevent problems with electrical conductivity that can damage the torch’s front-end parts.
4. Visually inspect the nozzle to look for distortion, cracking, or blackening, as these are signs of wear that can lead to improper shielding gas coverage. Replace the nozzle if any such damage is evident.
5. Check for cracks in the handle by inserting a wooden dowel or your finger into the back end of the torch; this increases the diameter of the handle and makes for easier visual inspection. Replace (do not tape!) the handle if damaged in order to avoid injury from shocks.
6. Visually inspect the silicon rubber insulation surrounding the torch body for any cuts. Check a phenolic torch body for cracks. Replace either torch body if any irregularities are found.
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