MIG Welding Technique
The Voice: Hey, Kevin. You often talk about TIG welding, MIG welding, oxygen acetylene and stick welding. Can you demonstrate what MIG welding is?
Kevin Caron: Sure. I can show you how to do MIG welding. Would you like to look inside the machine at all the MIG welder parts? Here, let me show you - this is my Miller MIG welder.
It's a 251, if you want to go look that up on the Internet. It's got a voltage control, and pretty lights. This part sets the voltage, this is the wire feed speed; how fast the wire comes out when you pull the trigger. And here is the on/off switch.
This part is the connector for the aluminum welding gun; the "spool gun," as they call it. That's the part you plug in.
This is the little connector for the trigger in the steel welding gun. Let's take a look inside the welding gun, beginning with the ground. This is the ground. Most of them have a big spring clamp, but mine wore out so I put this little magnet on it.
It's a welding magnet, and all you have to do is hold it up to some nice, clean metal, such as this piece I'm working on in the studio for an outdoor sculpture commission, or whatever piece of steel you happen to be welding. You simply turn that little knob and there you have your ground.
Make sure you clean off the metal before you place your ground. Wherever you're going to attach it, make sure you clean it off with your grinder or a file to make sure you've got a good ground. Otherwise, you're going to have trouble.
Take a look inside this part at this big spool of wire. This is a 30-pound wire; it's steel welding wire: mild steel. But it has a copper coating on it, just to help preserve it so the wire doesn't rust.
This part is the drive unit, where the wire comes off the spool and feeds through. It goes out into the cable that goes out to the gun and eventually comes out on the other end.
Begin by unspooling a little wire from your reel, feed it through to the other end, get it stuck through this part then close it and that section locks closed.
This is a tension knob to adjust how much tension is put on the wire so that it feeds correctly. It's pretty straight-forward and easy to do.
Let's now talk about how to set your voltage and your wire feed. The Miller is really nice in that it comes with information such as what's on this big sheet. It indicates what type of wire to use when welding various materials and types of projects.
It also suggests the type of gas, the different diameters of the wire, and the thickness of the metal: half-inch, three-eighths, quarter inch and so on, all the way down to 22 gauge.
The specs also tell you what to use for eighth-inch steel, suggesting 35 thousandths wire, which is what I have in the machine. They go on to suggest 20 volts and 220 inches per second. That's what they suggest you start at.
You may have to make changes for your specific welding conditions. For example, you'll need to consider where you are: are you inside, outside, vertical, etc. I consult the specifications continually while working on my steel sculptures.
However, if I'm doing a lot of MIG welding on one big project, such as Arabesque, one of my large sound features, I can normally set it and the settings pretty much stay where they are.
But if I'm working on a number of little jobs, such as my smaller home and garden sculptures, or if I haul it outside to fix a trailer hitch, or out front to fix the fence, then yes, I'm adjusting the knobs and doing different settings on it. Also, I frequently look at the specs on the chart just to remind me so I don?t have to remember all of that in my head.
This machine runs solid-core wire, so I've got shielding gas in this big tank. It contains argon and carbon dioxide. You can also run straight carbon dioxide. It doesn't make as nice of a weld, doesn't give as much penetration. The mixed gas works better.
There's even a triple gas. It's a blend of argon, carbon dioxide, and helium. It works a little better than this does, but the cost is a little more.
Let's talk about the regulator, it shows you the amount of pressure in the bottle and your working pressure for how much gas is actually coming out of the end of the nozzle. We?ll need 110. We're now ready to make sparks and weld metal together.
Time to put on some leather safety gloves, and I'll show you how to do MIG welding. Here's some eighth-inch plate that I got out of the scrap barrel. You can see it's all shiny because I cleaned it up with a big handheld grinder. It's important to get all the rust off, and all the scale. Nice, clean metal works a lot better.
We're using a couple of little pieces of stainless steel to play with. Begin by clamping them to your workbench. It helps keep them from running away while you're welding. I don't recommend grounding it to your metal workbench, because you can get in between the ground and the weld and get shocked.
It's a lot better if you take your ground and put it right on your work. That's what makes the magnet so valuable while welding. If you've got a big piece of metal and no place to clamp a ground, you can always stick on a magnet.
Remember, there will be lots of sparks and lots heat. Put those leather gloves on and no sneakers. Turn your machine on. Make sure your gas is turned on. As soon as you pull the trigger, the wire will start to come out and you'll start welding.
You don't have to scratch it, and you don't have to tap it like an old stick welder. Just get within about an eighth to a quarter inch of clearance from your metal, pull the trigger, and away you go. Watch out!
It's that quick and that easy. Practice, practice, practice!
See you next time.
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