Choosing a Welder: MIG, TIG, Arc or Oxygen-Acetylene?
The Voice: Hey, Kevin. What are you doing?
Kevin Caron: I'm just playing around with a couple of pieces of metal here in the studio, part of a contemporary art sculpture I'm working on.
I had a question the other day from one of my YouTube video subscribers: How do you choose which welder? Do you MIG it? Do you TIG it? Do you arc it (a stick welder)? Do you oxy-acetylene it? How do you choose, assuming you have the capability?
I thought that was a good question to explore in a how-to video on welding equipment.
When you have short pieces of metal with a really nice fit; a nice, tight seam; I would probably use a TIG welder. It's quicker, better looking, and has better penetration. There's less to clean up.
For thicker metals of up to about a quarter-inch, I would TIG it, for little short runs like this.
If you've got a thinner piece - this is eighth-inch plate, and this is sixteen gauge metal - I wanted to tack these two pieces together, but you can see that it's not a very good fit. There's a little gap in there that I could come in and tack with a MIG welder. It's one-handed, so I've got a hand free to do my work and get it the way I want. It's quick and it's easy.
Then I can come back with the TIG later, once I've gotten a better seam on the other side; my outside. Once I've got it all tacked on the inside, I can come along with the TIG and get a nice bead on the outside that's nice and clean, with very little to grind.
The TIG has a foot pedal, so I can keep it cooler as I'm welding. I can control my temperature with my foot pedal; whereas with the MIG it's set on the machine, so I'd have to stop welding and go back over there.
The Voice: How about filling gaps?
Kevin Caron: Let's take this little gap in the metal right here. With the MIG I can easily turn the voltage down a little. I can turn the wire feed up a little, so I'm filling a little quicker and I can come in and slowly fill that gap in rather than having to cut it oversize, then cut a patch, put the patch inside and then fill that back in.
Now, keep in mind, this is something you would do on a sculpture, a piece of metal art - something that is not critical, such as a bridge or an airplane or something like that.
With the TIG, you can do that also, because you can cool it down as you're working along. I would probably do it with the MIG because it's a little quicker, a little easier. Then I could always come back with the TIG and get all the little spots later.
The Voice: How about for a long run?
Kevin Caron: For the long runs, that's where the MIG really excels, because you've got something like three miles worth of wire to work with. I don't know how many yards it is, but it's a bunch, allowing you to sit here and weld all day long and never lift your finger off the trigger, thanks to all that wire.
With the TIG, you've only got one little stick. When you run out of this stick, you have to stop and get another stick, or somebody's got to hand you one so you can keep going. After a while that torch gets so hot that you can't even hold the torch. So, it depends on what you're doing.
The Voice: How about stick? When would you use a stick welder; an arc welder?
Kevin Caron: I only use the arc welder anymore when I'm working outdoors in the wind. That's where the arc welder really comes into its own; it's because there's no gas. It's got the flux already on the rod. It works outside; works in the rain. I've done it a couple of times. That's what it's best for.
But when I'm inside, I'll use one of the gas-shielded machines simply because I get a better-looking weld out of it than having to deal with the flux, then chipping off the flux and grinding.
The Voice: How about oxy-acetylene?
Kevin Caron: When you look at the sizes of the tips on the TIG, and on the MIG, notice they have a very small area where there's actually flame. There's where your heat is; where your welding is going on. It's a very tiny area that you're actually going to heat compared to oxy-acetylene. Oxy-acetylene is a much bigger flame, so you're going to heat the area that much more.
With the thicker metals, that's OK. You can get away with it. With the thinner metals, the oxy-acetylene will warp the metal because of all that extra heat. These (TIG and MIG) are a little bit colder than the oxy-acetylene is. With thicker metals, I'd use oxy-acetylene; outdoors I might use oxy-acetylene. If I was going to weld and bend the metal, I would definitely use the oxy-acetylene.
So that's how I would look at it: nice fit, use the TIG. Got a little gap, a little rough edges, or, if I had cut it with the plasma cutter and not ground everything perfectly smooth and my fit was a little wobbly with holes to fill in, I'd use the MIG. I'd turn up the wire feed a little bit so I can make up for all those little gaps; all that poor fit in there.
The Voice: How about the fun factor?
Kevin Caron: The fun factor? Wow. Both machines are actually a lot of fun to use. I enjoy using both of them.
The MIG, because of that long run, allows you to stand there and just weld and weld and have a lot of fun with that, watching the weld as it's happening.
The TIG is much more skill-oriented. It takes much more patience, but it sure is fun when you're welding and can see the flame off the tip and watch it melt the metal. You can melt your base metal around it and add your filler rod and you can actually see it going on inside there. That's always cool. It's like holding a lightning bolt in your hand and you're melting this metal together.
Both of them are fun. I prefer TIG over MIG, just for the fun factor of it, though. That's personal.
Well, let me play with this welding tool a little more. I'll see you next time.
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