How to Bend Metal Using Oxygen Acetylene
The Voice: Hey, Kevin. What are you doing?
Kevin Caron: I'm here in the studio putting some more bends in this piece of one-inch, solid metal rod. It's a tree bark pattern that I use to make some of my home and garden sculptures.
To bend it I'm going to need the oxygen-acetylene torch, because you just can't bend metal rod by hand. So, we'll heat it up in a couple of places. Do you want to watch?
The Voice: You bet.
Kevin Caron: Come over here and see this great little vice. Not only does the head swivel in all different directions, but it's got this great little pipe jaw inside, so I can put my piece down in there and as soon as you tighten the jaw, that doesn't swivel anymore.
Let's get our dark welding glasses, oxygen-acetylene torch and this tip. Come in close so you can see this. This is called a rosebud tip or a heating tip. They come in several different sizes.
This one is a number 4. This one is a number 8. The only difference between the two is one has two more holes than the other, which allows you to get a little more flame out of it. This one heats up a lot quicker (a lot bigger area) than this one will. But this one uses gas a lot faster than this one will. So, we'll use this one today.
Because the piece is so short, I?ll use my mechanical fingers.
When I start to heat some especially thick metal such as this, I'm going to stay right in one spot until it starts to get red. Some people like to work all around and up and down. I think it heats up a little quicker if I just hold it right there and let it get red hot, then I can move around.
The Voice: How do you know when it's hot enough?
Kevin Caron: With the dark glasses on, it looks more orange right now than it does red. So once I get this up to a nice, bright red, with the glasses on, then I think it's ready to bend. It doesn't take a whole lot of pressure. Anybody can do it, as long as you get it hot enough.
As you can see, once you start your bend, you can start moving up around the heat. Move up to where you've got it red hot, then move up to where it's a bit colder and get that hot, letting the other end start to cool. And you can control your bend a little better to get a nice, smooth bend in it, rather than all herky-jerky. And, yes, that's a technical word.
The Voice: Can you burn it if you raise the flame on there too much?
Kevin Caron: Oh, yes. If you get too close to it or you hold your flame in one place too long, you'll actually start to burn the carbon right out of the steel. It will actually turn it more back into iron, like the iron ore rather than steel, which has the carbon mixed into it. And that makes it brittle; it ruins the tree bark pattern and makes it look it a little different. It's not a good thing.
Now my wrench is starting to get hot, so I'm going to get that out of the way until I can get it hot again; then can I go back in and get a little more bend on it. If I was going to be doing this a lot; several pieces or a big, long piece, I'd have a bucket of water so I could drop my wrench down into it and let the wrench cool off.
The Voice: Do you ever cool the piece itself as you're heating up?
Kevin Caron: Well, that's another way to control the bending. You can take a squirt bottle, come on the back side of the heat and squirt it with a squirt bottle. That cools that area down so you can get it hot somewhere else. It's another way to control the bend.
Notice all this stuff flaking off right here; this is just the scale from when they manufactured it at the foundry. Now I'm just burning the scale off.
So I'm just getting it a little bit hotter; got my torch out of the way. Now I can come back and grab it with both hands, but I don't want to grab it right now.
And that's bending metal with the oxygen-acetylene torch, using different sized tips; all kinds of cool metal working equipment.
Hang on a minute. Just to show you how hot it is - this is an infrared thermometer. It won't even register on the three-digit gauge, which means it's up over a thousand degrees. Yeah, that'll leave a mark.
Well, I'm going to go get this cold now in the sink so I can go back to work.
I'll see you all next time.
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