September 12, 2006
Once you know some basic information about the equipment on the front of your GTAW torch, you can get the right parts for your application and start improving your welding performance.
An industry-standard manual gas tungsten arc welding (GTAW) torch package includes a torch body and a cable set, either 12-1/2 or 25 feet long. Front-end parts generally aren't included. While it may sound like the manufacturers are being cheap, it's really in your best interest, because it lets you customize your torch for the job at hand or to use front-end parts already in stock.
Everything from the handle forward is considered a front-end part. This includes gaskets, nozzles, collets, and collet bodies that make the torch functional. Typically, the torch body in a package will have the Teflon® gasket installed (see Figure 1). The gasket insulates the torch body from the gas nozzle. A torch package also may come with a back cap—but it may not be the one you need.
The most common styles of torches are the 17, 18, and 26 series that use the 10N series front-end parts (see Figure 2) and the 9 or 20 series torches that use the 13N series front-end parts (see Figure 3).
Most of these parts are standardized, meaning that a part from one manufacturer will fit another manufacturer's GTAW torch. Be sure to ask before you buy, though, because some torch manufacturers make parts that fit only their torches.
This 20 series GTAW torch has a medium back cap and a Teflon gasket.
To determine which front-end parts you need, first decide the type and thickness of the material you'll be welding. This will help you select which tungsten electrode type and diameter you'll need and, in turn, which size nozzle you'll need. For example, if you plan to weld 1/8-inch aluminum you'll probably choose a 3/32-in.-dia. pure tungsten electrode (AWS Classification EWP, green band), so you'll need the 3/32-in. collet and collet body and a No. 6 or 7 nozzle. On the other hand, you might choose a rare-earth tungsten (AWS Classification EWG, gray or cream band) instead.
Many equipment manufacturers offer GTAW calculators on their Web sites, in their operations guides, or as a pocket reference chart at little or no charge. These calculators are a good place to start and usually include additional information, such as recommended shield gas flow rate and amperage, but you'll need to test to be sure.
This 10N series collet and collet body are shown with a Teflon gasket.
This 13N series gas lens collet body and collet are shown with an alumina nozzle and Teflon gasket.
GTAW nozzles are measured at the side of the nozzle farthest from the torch body in 1/16-in. increments at the inside diameter. For example, a No. 4 nozzle is 1/4 in.—or 4/16 in.—in diameter. With the exception of a specialty torch, such as one for microwelding, the smallest nozzle is the No. 4 and the largest is a No. 16, or 1-in. nozzle.
Nozzles can be made of alumina, lava, Pyrex®, or quartz.
This 13N series collet and collet body are shown with an alumina nozzle and a Teflon gasket.
This 10N series gas lens collet has a lava nozzle and a Teflon gasket.
Most GTAW torch manufacturers offer basic accessory kits that include a short back cap, a basic set of alumina nozzles, an assortment of tungsten electrodes (usually 2 percent thoriated), and collets and collet bodies in the most common sizes: 0.040 in. to 1/8 in. These accessory kits usually are a good place to start, but when you're ready to optimize your torch for a variety of applications, you'll need more front-end tools in your box and on your torch.
With basic torch knowledge in hand, you should be armed and ready to find the best grouping of front-end parts to help improve your GTAW performance. The following are three steps you can take to enhance your GTAW experience:
|Parts Versus Consumables|
| The word consumable traditionally has referred to material that's consumed within the weld or in the process of welding. Wire, rod, tungsten electrodes, and shielding gas are consumables. Front-end parts often are considered consumables because they wear out or break and need to be replaced. |
While they may not be the most inexpensive, well-manufactured GTAW torch accessories are engineered to work together, eliminate tolerance stack-up problems, provide proper torch insulation, and prevent gas leaks.
Make sure all the parts of your torch fit together properly to ensure that oxygen doesn't leak into your weld zone and cause contamination.
Note: if you're grinding thoriated tungsten, make sure to control and collect the dust, have an adequate ventilation system at the grinding station, and follow manufacturer's warnings, instructions, and material safety data sheets.
Jennifer Simpson is marketing manager for Arc-Zone.com Inc., 2091 Las Palmas Drive, Suite C, Carlsbad, CA 92011-1551, 800-944-2243, firstname.lastname@example.org, www.arc-zone.com. Introductory photo courtesy of Miller Electric Mfg. Co., Appleton, Wis.
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