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misterW
01-30-2011, 04:29 PM
I need to bend some copper pipe to about 90 degrees. I have bent pipe in the past using a torch and a rounded object to bend it against, but I heard it mentioned that one can do this using ice as well. That is, freezing water inside the pipe and then bending it while the ice prevents kinks.

However, I am wondering if there is more to it than that. It seems the ice would break and then perhaps allow the pipe to kink. Somebody on the internet mentioned using a frozen ice/detergent mixture...

Anyone ever used the ice method for bending pipe? I'm curious to see how it works, and upstate NY in winter is a great place to freeze pipes.....

johnpost
01-30-2011, 04:55 PM
you don't need heat to bend just a right angle on a curve.

sand does work with a curve to bend against..

Chronos
01-30-2011, 05:16 PM
There are pipe-bending tools with a circular cross-section groove that fits the pipe and is bent around a curve, with a hook to hold the pipe in place and a long lever arm. The sides of the groove prevent the pipe from kinking, since a kink would be wider than the groove.

misterW
01-30-2011, 07:36 PM
I'm aware of the sand method and the bending tool method.

Just curious if anyone out there is knowledgeable about the ice method.

rbroome
01-30-2011, 08:08 PM
I have no idea how hard it is to obtain, but check out Woods metal:
http://en.wikipedia.org/wiki/Wood%27s_metal

Canadjun
01-30-2011, 08:56 PM
However, I am wondering if there is more to it than that. It seems the ice would break and then perhaps allow the pipe to kink.

Even if the ice shattered (as I assume it would), it is still occupying the space, is incompressible, and is held in place by the ice around it. For the pipe to kink it would have to be able to reduce the space that the ice is occupying.

Surreal
01-31-2011, 01:04 AM
For most common materials (especially very ductile materials like copper) you can bend a full 180 degrees without kinking provided your bend radius is at least 1.5X the OD.

I've not heard of using ice to bend pipe but I have heard of using low melting temperature metals such as solder and tin.

longPath
01-31-2011, 07:30 AM
I saw a segment on one of thiose "How it's Made" programs where they showed a trumpet being constructed.
The tubing was filled with soap and water (Quite a thick solution), frozen to =41, then bent in a jig.

Here is a link to the item: http://www.youtube.com/watch?v=kh7RrlazaRc

The bending operation starts at about 3:15.

Moonshiner
01-31-2011, 08:31 AM
If you fill a copper pipe with water and freeze it the pipe will split.

That's probably why the trumpet makers use a soap solution. They're trying to keep it from freezing solid.

misterW
01-31-2011, 09:52 AM
If you fill a copper pipe with water and freeze it the pipe will split.

Even if the pipe is open on one end?

electronbee
01-31-2011, 07:27 PM
Even if the pipe is open on one end?

It can. It depends on how much water and the diameter of the pipe. I had an aluminum lamp post, that water got into, and it split from ice formation on the bottom near the ground. When I looked in the water was only a quarter of the way high.

Different material, I know.

johnpost
01-31-2011, 08:09 PM
If you fill a copper pipe with water and freeze it the pipe will split.

Even if the pipe is open on one end?

when the water surface freezes it then becomes a closed pipe.