From http://www.Weld.com and http://www.kevincaron.com – Wyatt “Mr. TIG” Swaim and Kevin Caron tackle when to use TIG and when to use MIG welding ….
Caron says TIG welding precise and clean – there is little or no clean up. He does his structural welds with his TIG, but if he has 10 or 15 feet to weld, the TIG is much slower. He probably has to use his angle grinder to smooth the weld, but he gets his work done.
Swaim likes the precision, the ability to weld aluminum, stainless steel, etc. with the same machine and the same gas. He says MIG welding steel makes sense, but he finds MIG welding aluminum very difficult.
Caron says they do have push-pull guns that have another set of rollers to help pull the wire so you can do about a 15-foot welding run. But the push-pull gun is almost the same size as a spool gun and is expensive.
Caron shows the TIG torch and the pedal, because this torch doesn’t have a trigger on it like some TIG welding torches do. Just like a car gas pedal, the harder you push the pedal, the more electricity goes to the torch, the hotter the arc, the faster you weld. The torch has body and a gas lens. The graphics show the gas with and without the lens, illustrating how straight and smooth the gas comes out when using the lens.
Then he shows the tungsten. Swain says he carries tungstens of many sizes at TIGDepot.net, from 20/1000s diameter up to 1/4 inch diameter for heavy duty welding. Caron then shows the collet body and the collet, then the back cap. Then he shows how the tungsten goes inside.
Then he adds the TIG cup to control the flow of the argon gas. The cups come in different diameters. Caron adds that a smaller cup also lets you get into tighter spaces, while the bigger TIG cups give you wider coverage.
Then Caron shows the MIG gun, or MIG torch. It has a trigger and a nozzle. It also has a tip, or electrode. He shows the brass connector that holds the liner in the cable that the wire feeds through to make it easier on the feed roller. There are also holes to allow the inert gas to come through the nozzle to shield your work.
Caron explains you normally use 75% argon and 25% CO2, which is commonly called a MIG mix, or MIG gas. Occasionally you’ll use what’s called a tri-mix, which is argon and carbon monoxide with a little helium to boost the heat a little for harder metal.
Then there’s filler rod. With TIG, you have a three-handed process – or two hands and a foot. You have to hold the torch, feed the filler rod, and run the electricity with the foot pedal. So when you want to tack, you need another hand to hold it in place. Caron says Swain is probably a lot better tacking with the TIG welder. Caron likes to have both machines, so when he tack welds, he reaches for the MIG, because you use one hand for the gun and the other hand to hold your work. Then he does his finish work with the TIG. The MIG has a little splatter. It’s not nearly as bad as using a stick (arc) welder as there’s no slag to clean up.
They have a Lincoln SP-135 Plus 110-volt MIG welder with solid-core wire and gas, as well as some 16 gauge and some 1/2″ plate to show what it can do. Inside, it has a spool of wire, a feed roller that sends the wire out the gun. There’s a positive and negative connection that is switched to accommodate solid-core wire or flux core wire (flux core is used without gas). The connections are also changed when you use a spool gun. On the front of the machine is the on-off switch, an arc-volts dial, and a wire speed dial.
With a pull of the trigger, he MIG welds the 16 gauge easily. Now he turns up the voltage all the way, turns up the wire speed, and welds the 1/2″ plate. For the 1/2″, Caron would usually use a 200- or 250-amp machine, although he has preheated thick metal with the oxygen-acetylene torch and come back with a lower powered machine to weld it.
Caron says if you can afford a little more power, get it. It’s still a handy machine, though, even for Caron when he has to go outside or places he doesn’t have 220.
For more how-to videos, visit http://www.kevincaron.com and http://www.weld.com , where you can ask questions on the Weekend Warrior forum.
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