How to Weld Thin Metal to Thick Metal
The Voice: Hey, Kevin. What are you playing with?
Kevin Caron: I got a question from a YouTube subscriber the other day: How do you weld really thin metal to thick metal? He's been working on his race car, and it just keeps blowing right through the door skins and making a mess!
I thought I would show you a couple of tricks...
I just cleaned up the eighth-inch metal plate a little; this is the 22-gauge. Now I'll just hold it together, put a couple of little tacks on it, and then show you how to weld it.
First, there's something you've got to keep in mind when you're working with the thin and the thick. Come and look down here.
Because this metal is so thin, the 22-gauge sheet, the door panel - whatever it is that you're working on - you're going to want to do this: instead of coming down your joint, or trying to weave back and forth like you would on a normal weld such as this piece of eighth-inch steel plate, you'll want to keep all your heat over here on the thicker plate. Then make sure you work along the edge of your joint just enough so that the puddle can come up and get into your thinner metal.
It's tricky. It takes a little practice to do it, so let's put the goggles on and take a look at it.
As I mentioned, you're going to start on the thick metal and just let your puddle kind of lap up a little. You're not going to want to sit here and weave back and forth like you would on a thicker piece.
Here we go. (welding)
Just a little bit. Now I'm going to come around and get it here. (welding)
Eh, let me get it one more time. (welding)
Did you see what I was doing? It's just enough to keep the heat down on your thicker metal, wherever that may be. Then you can go ahead and splash it a little. Let the puddle just flow up a little; catch it with the edge of the puddle.
Now put your helmet back on and we'll just run a little bead along there so you can get a better look at it. (welding)
Did you see how I was doing that? Keep all your heat - most of your heat, a good 80 to 90 percent of your heat, down low on your thicker metal.
Remember, you have to have your amperage set or your voltage set for your thicker metal because you have to be able to get penetration into that; you know you're going to get penetration into the thinner stuff, so don't turn your welder down too far. Make sure you get enough penetration for your thick stuff.
Right now my 251 Miller is set at 19 and a half volts and 283 inches. And this is 035 wire running on just a mixed gas: carbon dioxide and argon.
Let me go ahead and get this one last little piece. Put your helmet back on so you can watch some more. (welding)
You see, it even caught me one time. There, right there on the edge, right here in the corner where it blew through on the thinner metal? It got just a little too hot; came up a little too high and snapped right there.
So, just remember, keep most of your heat on your thicker metal. Keep your welder set for your thicker metal. Don't stand still - keep moving and you should be fine.
Hope that answers your question. See ya.
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