[Editor’s Note: This article originally appeared in the August 2013 issue of Grassroots Motorsports.]
Anything is possible with enough sheer force. From lifting a car to building skyscrapers to putting a man on the moon, humanity has used this technique to overcome every obstacle–even connecting two pieces of metal.
Welding used to take a blacksmith hours using a process called forge welding. The process is simple but labor-intensive: Heat two pieces of metal in the forge, put them on top of each other, and hammer them together. Force, once again, had solved a problem.
This simple process kept humanity advancing until the end of the 19th century, when it became apparent that something better was needed. Arc welding, oxy-fuel welding, and electric resistance welding were invented as quicker, easier ways to join metal.
Today, the average shade-tree mechanic can be a welder–no forge or sheer force required. Quality metal inert gas welders are simple enough that even a 10-year-old can use one. MIG welders have turned tasks that would have been impossible 150 years ago, like building a roll cage, into fun weekend projects.
However, if MIG welding is so common a kid can do it, why hasn’t tungsten inert gas, or TIG, welding become easy and accessible?
Lincoln Electric, a company with welding at its core, says it has. And in the last few years, prices for TIG machines have come down.
Before we talk too much about the intricacies of welding, let’s take a moment to review the basics.
Welding is a way to join two pieces of metal together. To melt the metals, heat is applied, usually in the form of an electric arc. This arc melts the metals into what is referred to as a weld pool. A filler material is then melted into the weld pool.
After the weld cools, the result is a strong, compact, reinforced joint. Besides producing a lighter result–and often being an easier process–than other means of fastening two metal objects together, welding also allows for much more intricate joints than bolts or rivets.
MIG Welding: MIG and TIG welders share two letters of their names, both use an electric arc to melt metal, and both look similar to the naked eye. However, they fuse two pieces of metal using very different methods.
In MIG welding, the electrode is also the filler rod, and it’s automatically fed into the weld pool by the welder itself. After the operator chooses the right setting, MIG welding is basically a point-and-shoot process: It’s quick, self-contained, and can easily create strong welds.
However, what MIG welding boasts in speed and ease, it lacks in control. Once the welder strikes an arc, the machine maintains exactly the same power and feed rate. This makes it poorly suited for temperamental metals like aluminum or thin steel, which require a bit more finesse.
TIG Welding: TIG welding gives the operator much more control over individual events in a weld: how much power is added at any one moment, the timing and placement of the filler rod, and the speed at which the filler rod is inserted.
If this sounds more complicated than point and shoot, it is. But with this difficulty comes the opportunity to create perfect welds in almost any material. “Almost any material,” of course, includes aluminum.
Plus, which sounds cooler: “I’m a MIG welder,” or, “I’m a TIG welder–who also wrestles bears”? See? The choice is a no-brainer. If metals were people and welders were suits, then MIG would be the gray off-the-rack special. TIG would be the custom-tailored show-stopper.
Coincidentally, training to wrestle a bear is analogous to learning how to TIG weld. Both require an expert to explain the ropes, so Ron Lenz offered to share some tips. Custom fabricator by day and welding instructor by night, Ron was willing to show us how he teaches TIG welding in just one evening–yes, one evening.
Ron basically lives behind a welding mask, and he’s even appeared as an expert on Spike TV’s “Search and Restore.” Could he really pass along those skills in a single night? We’d see.
Before we began, though, we had to set up our new welder, a Lincoln Electric Precision TIG 225. Lincoln bills it as one of their best consumer TIG machines. Compared to the starter TIG machines, this one can handle aluminum as well as metals beyond mild steel.
First, we gathered the consumables–which Ron details in an itemized, color-coded list: 100-percent-tungsten electrode, 100-percent-Argon gas, 3/16-inch aluminum filler rod, and a new stainless-steel wire brush.
Assembling the machine wasn’t hard at all, and we soon had the gas bottle hooked up, the electrode installed in the torch, the filler rod unwrapped, and the machine plugged in. We were ready to weld–or so we thought.
It’s true that we could have technically started welding the instant our machine was turned on. But without any safety gear, that would have been one very memorable welding session.
When operating a welder, you’re subject to burns–and not just the obvious flash burns from the bright arc or the kind that come from heat. Welding produces intense ultraviolet light, so being covered from head to toe is paramount (unless you’d like to get a nice cancer-tan while you’re welding).
Our TIG welder was set up. Our human welder was suited up. And our (also human) instructor was present. It was finally time to start welding! What would our first project be? An aluminum space frame? A cool gauge bracket? A bear?
Nope. Our first project was to finish setting up the welder. We had already connected our new gas bottle, but as it turns out, we needed to adjust the regulator. We made sure we had a steady 15 CFH, or 20 psi, of Argon when the welder’s solenoid was open. When we weld materials with different requirements, we’ll need to adjust this gas flow accordingly.
Then Ron pointed out that we still needed to “ball the tip” of our electrode. The electric arc is produced by the electrode, and forming the tip into a ball makes a reliable, consistent arc easier to obtain. We accomplished this by using very high DC positive power, which melted the electrode into a shiny ball. Now we were finally ready.
How We Did It
1. Lincoln’s Precision TIG 225 could be considered overkill for our initial foray into TIG welding, but we didn’t want to be limited by our choice of welder. We don’t like outgrowing our equipment.
2. We used a simple, air-cooled torch. It gets quite hot during prolonged welding sessions, which is why many pros, including our teacher, Ron Lenz, use more complex water-cooled units.
3. Unlike MIG welders, which use a hand trigger to modulate power, TIG welders use a continuously variable foot pedal. It allows for precise adjustments on the fly.
4. The most important parts of any weld are a stable work surface and a great ground. We used a vise and a spare piece of aluminum as our base.
5. Ron Lenz is an automotive expert with a knack for TIG welding, so he was the perfect teacher for us beginners.
6. Our new welder came with a high-quality regulator. This is a great thing, as we’ll need to adjust it as we weld together all sorts of different projects.
7. Just like racing, welding requires safety gear from head to toe. Lincoln Electric supplies more than just welders, as they also offer fire-resistant welding jackets and gloves as well as helmets with automatically darkening visors. They even have a comfortable welding hat that prevents chafing. We completed the package with sturdy jeans and closed-toe shoes, which should always be worn in the garage.
8. Step one of any weld is to get the surface as clean as possible. We devoted a brush to only aluminum, which should reduce contamination.
9. We bent the ends of each fill rod, as they are sharp and can poke unsuspecting onlookers.
10. Finding a comfortable welding position is vital. For Ron, this means wrapping the torch around his arm a few times, sitting in chair, and holding the torch like a pencil. Each person will have a slightly different method, so experiment with different positions.
11. Holding the torch at a slight angle allows the operator to see the weld better.
12. Lincoln provides a handy cheat sheet specifying how to set up a TIG welder for each type and thickness of material.
13. First, Ron had us practice simply striking an arc and moving the torch across the metal. Once we mastered that, he promised, we’d advance to using filler rod. This was way harder than it looked.
We spent at least an hour moving the torch in little circles. The hardest part was something we hadn’t expected: constantly varying the welder’s power. We needed lots of power initially to start the arc, then much less, modulated precisely, to keep it the same size.
Once the torch had reached the end of the weld, the job still wasn’t done. We had to slowly back off the power because suddenly dropping the arc creates a depression, weakening the weld. TIG welding would be merely hard if it only consisted of modulating a pedal. However, we had to simultaneously manage the torch and the weld pool, making it all nearly impossible. TIG welding was eerily similar to patting your head while rubbing your belly (or bear wrestling). But after a lot of trial and error, we were able to create the “stacked coins” welding pattern Ron expected of us.
14. With Ron’s continued guidance, each attempt was looking better and better. Some even looked like a sentient being had produced them. Then there was huge flash of light, and the weld stopped. We dropped the torch, yelped, and tore off our helmet to ask Ron what had just exploded.
To our surprise, he was laughing: We had simply “dipped the torch” and contaminated the electrode. This happens whenever the electrode touches the material during a weld. To fix it, we’d have to grind the contaminated tip off our electrode, then ball it again.
15. With the electrode fixed and more practice under our belts, it was time to add fill rod. This new, even harder task ruined what little confidence we’d gained, but after another hour or so of practice, we were comfortable making little raised bumps on the flat aluminum sheet. The process ran like poorly made clockwork: Hold the torch near the metal, floor the pedal, yelp when the arc starts, back off the pedal, move the torch in little circles across the metal, and dab a little fill rod into the weld pool every so often. We were finally beginning to feel like TIG welders.
16. It was time for a real welding task: “Weld two pieces of flat aluminum to each other,” Ron told us. So we bravely struck an arc, waved the torch, and deposited the fill rod. The result was a passable, if not perfect, TIG weld. Did this mean we could finally start making suspension parts?
No, as it turns out. Ron picked up our work, felt the raised weld with his fingers, then easily snapped the two pieces apart. “Aluminum is hard to penetrate; it dissipates heat very quickly,” he said. Yet again, our excitement had been crushed.
17. Upon examining the pieces, we could see what we had done wrong. We needed more power and more fill rod, along with a steadier foot controlling the power.
18. After several more tries, we were able to produce a passable weld. It will be a long time before we start making parts for F1 cars, but no aluminum door handle bracket will ever stand in our way again.