March 7, 2006
George Bright and David Anthony were two welders with the same goal: to upgrade their GTAW system. Learn about their experiences and gain some insight into what you need to know to upgrade from an air-cooled to a water-cooled GTAW system.
|David Anthony, who builds custom choppers from sheet metal, learned GTAW to gain more control of the entire design process. In using GTAW, he found that upgrading to a water cooling system was necessary.|
What does a retired 65-year-old in New Mexico have in common with a young custom chopper designer in San Diego? Not much, except when it comes to gas tungsten arc welding (GTAW).
George Bright retired "from a lot of things" a couple of years ago: 20 years in the U.S. Air Force, an upholstery business, and his position as manager of an Albuquerque school district data center. Restoring old Volkswagens led Bright to welding. After he rebuilt some aluminum seats on his boat and burned his hands a couple of times, he realized it was time to upgrade to a water-cooled GTAW torch.
Four years ago David Anthony started designing custom choppers in San Diego. At first he bought prefabricated parts and contracted out custom work. Two years ago he taught himself to gas weld, and soon after he learned GTAW.
Anthony also got tired of burning his hands, "especially when you're doing a long run on a seam. I'd be in a hurry to finish before my torch got too hot." He also decided to upgrade.
As Bright and Anthony did, you'll need to keep several considerations in mind if you want to upgrade your GTAW system successfully.
First you'll need a water-cooled GTAW torch. Several types of torches are on the market, but generally the most popular is the 20 series. These torches deliver 250 amps; the torch body weighs 3 ounces; and the torch handle diameter is 3/4 inch.
You'll also need a method for directing cool water into the torch head. You can hook up your torch to your city water supply or buy or build a water cooler.
Hooking up to City Water. The most inexpensive option is to hook your torch up to your city water supply. Whether you're connecting your torch to an outside spigot or a sink inside your weld shop, you'll need to get tubing and a variety of fittings. You can get some couplers at a hardware store, but only welding supply stores sell those that connect your water lines to your torch.
You'll also need to drain the water by running a line from your torch's water return out to your garden, floor drain, or sink. Be sure to get a water pressure regulator for water entering your torch, because high water pressure can damage the torch.
In all, these parts cost about $30; many fabricators have used this method successfully for years. Although it's inexpensive, it does have some disadvantages. You will expose your torch's cables and small internal passages to minerals and additives in the water, which can clog and ultimately overheat your torch. Also, it's easy to forget to turn the water on or off. In addition, handling the lines in and out of your weld shop can be cumbersome.
Building a Closed-loop System. A closed-loop system can provide cooling for your torch with a low risk of introducing contaminants or particulates that can clog it. Both Bright and Anthony wanted the benefits of a water cooler, but each chose a different path.
Bright didn't want to spend $700 for a water cooler or even $400 for a small, light-duty unit, so he decided to build his own. He started with his wife's 1970 model turkey roasting pan that holds three gallons of water and a lot of advice from fellow fabricators, courtesy of Internet chat boards. Then he had to get a pump, motor, radiator, and fan, and figure out how to put them all together.
Although Bright knew he could construct a water cooler without a radiator if he had a reservoir large enough, he also knew it would take up a lot of space. He wanted something more compact (see Figure 1).
"Some of the guys [on the Internet] are using pond pumps. I thought about using a bilge pump, but went with a PROCON® pump instead," Bright said. Most manufactured water coolers use a Series 1 PROCON vane pump with an integral inlet strainer that keeps particles not only out of the pump, but also out of the torch.
A new pump would cost more than $200, while a refurbished pump would be a little more than $100. Bright got his pump and motor from eBay for about $40, including shipping (see Figure 2).
Bright learned through his research that many PROCON pumps sold on eBay are manufactured for beverage dispensers and don't have a strainer. In addition, the default relief valve pressure setting is 250 pounds per square inch (PSI). Water cooler pumps usually are shipped preset at 60 PSI for gas metal arc welding (GMAW). For GTAW, he advised setting the pump at 50 PSI, the recommended maximum output rate for GTAW torches, and a flow rate of 1 quart per minute.
Bright spent about $170 and 20 hours "mostly trying to figure out what I wanted," he said. For him, it was an opportunity to learn and make something for himself. He said he'll try it out as soon as his 20 series GTAW torch arrives (see Figures 3and 4).
Buying, Hooking up a Closed-loop System. Anthony didn't even consider building his own water cooler; he had bikes to build and customers waiting. Time spent away from welding meant he would lose income.
When his welding supplier recommended adding a small, 10,000-British thermal unit (BTU) water cooler to his power supply and a new, weld-ready 20 series GTAW torch package for about $700, Anthony was intrigued. When the supplier offered to let him make payments, it was an offer he couldn't refuse. When his order arrived a couple of days later, Anthony said he set up his new torch and water cooler easily (seeFigure 5).
When you're setting up your system, be aware that industry-standard water-cooled GTAW torches come with three lines. One has a right-hand thread for gas hookup; another, which is sometimes blue, has a left-hand thread for cool water from the water cooler. The power cable, which goes back to the power supply, also carries the warm water, with a red water return line coming off the international-style connector to hook into the water cooler (see Figure 6).
Since upgrading to a water-cooled system, Anthony has noticed a significant savings in his argon consumption. "When you actually stop a weld, there's a five- to 10-second period when the gas is still going. If you're stopping a lot [with an air-cooled torch], you're using a lot of gas," he said.
In addition, Anthony can hold his torch comfortably with a steady hand, wearing just a thin deerskin glove. He's not in a hurry to finish a seam anymore either.
"I can wait longer, let the puddle form and just push it along. And the weld seams are so much nicer," he said.
And for a fabricator known for his stainless steel gas tanks, getting a nice seam impervious to gas vapors is critical.
|10 Tips for Setting up, Maintaining a Water-cooled GTAW System|
PROCON is a registered trademark of Procon® Products, 910 Ridgely Road, Murfreesboro, TN 37129, 615-890-5710, fax 615-896-7729, www.proconpumps.com.
The FABRICATOR® is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1971. Print subscriptions are free to qualified persons in North America involved in metal forming and fabricating.