How to Bend Tube and Pipe
The Voice: Hey, Kevin. What are you playing with?
Kevin Caron: One of my welding video subscribers posed the question: What's the difference between metal pipe and tubing?" It's a good question and it's pretty easy to show you using some samples I have here in the studio.
Can you see the wall thickness? Notice the difference between the two of them?
The Voice: Yes.
Kevin Caron: Pipe is thicker than tubing. You can use pipe in a hydraulic bender. Tubing, on the other hand, you would use in a mandrel bender or another pipe bending tool such as a conduit bender, like when you're running electrical wires.
The Voice: What's a mandrel bender?
Kevin Caron: A mandrel bender is a big piece of hydraulic equipment, and it's got a plug that goes down inside the tubing. You would put that plug down in and as you start to bend it in the machine, that plug is what keeps the pipe from collapsing because you're trying to shrink it on the inside of the bend and stretch it on the outside of the bend and keep the top and the bottom the same while trying to bend it around the corner.
That mandrel goes inside to help keep the pipe, or the tubing, the same diameter. Without it you would end up with the kink; that's why they put the mandrel down inside.
Here is another bending tool: the conduit bender. You can pick up one of these tools at Home Depot or Lowe's, if you want to do electrical work on your house. Electrical conduit is the tubing that you would run the wires through. You would you would put this flat on the ground, then pull on the handle at the same time, and that thing would just bend right over.
It's got a little level in it so you can go from horizontal to vertical and it shows you when you get a 90-degree bend. There are different sizes for the various sizes of conduit or tubing.
This pipe bender is a mechanical or a hand version rather than a hydraulic version.
The Voice: Can you bend metal tubing in the hydraulic bender?
Kevin Caron: You can, but the problem with doing it in the hydraulic bender is that it requires the right size die, or shoe, as it's called, to fit the tubing.
This one is a little loose inside, so when I try to bend it in the hydraulic bender, it's going to deform; it's going to flatten out a little and kink as I bend it around the corner. You've got to have the right bending machine for what you're doing - you can't just put it over your knee and give it a crank.
Some guys fill the tubing with sand and water. They seal one end, hold it up, fill it, wet it, cap it, and then that keeps it from kinking. But you really have to pack it down tight inside. It's quicker just to have the right tool to do the job of bending metal pipe and tubing.
I hope that answers your question.
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