How to bend a pipe, please.

mental4astro (Alexander) · #1 22-02-2013, 01:53 PM

Fellow IIS'ers,

Again I impose upon your collective knowledge.

I have a small project, and I need to put a small bend in 30mm steel pipe. Being without a pipe bender, how can I do it without causing the pipe to crush? The bend would be between 30 & 40degrees. Wall thickness of the pipe is 1mm.

Many thanks,

Mental.

Wavytone · #2 22-02-2013, 02:07 PM

Hi Alex, you have no chance unless you use a pipe bender. Thin wall stuff especially.

As a one-off, one way would be to ring around a few plumbers and find one that can do it if they're in the neighbourhood for a case of cold ones...

mental4astro (Alexander) · #3 22-02-2013, 02:12 PM

Thanks Wavy.

Any other trades I could try? Would a panel beater or car exhaust mob do it?

Larryp (Laurie) · #4 22-02-2013, 02:13 PM

Car exhaust mob should do it easily, Alex

Steffen · #5 22-02-2013, 02:38 PM

Kennards hire out pipe bending kits.

Apparently, filling the pipe with dry sand and plugging both ends lets you bend it without folding, 30 to 40 degrees should be doable that way. Some heat will probably help, too.

Cheers
Steffen.

EDIT: Also: http://www.metalgeek.com/archives/2005/05/01/000047.php

rogerco (Roger) · #6 22-02-2013, 02:52 PM

Yes to the sand, definitely heat especial the area that will be the outside of the bend because you are going to be stretching the steel. In a plumbing hardware store you will find long springs that are used instead of the sand, they go inside the pipe and stop it from crushing. But definitely heat otherwise you are trying to do what steel does best, resist stretching.

mental4astro (Alexander) · #7 22-02-2013, 03:01 PM

Blow torch ok? I have an oxypropane one.

PCH (Paul) · #8 22-02-2013, 03:34 PM

Hey Steffen,

that's very intuitive. I have a pipe bender from my days on the tools, but I confess I'd never have thought of sand. Very clever.

Quote:

Originally Posted by Steffen

Kennards hire out pipe bending kits.

Apparently, filling the pipe with dry sand and plugging both ends lets you bend it without folding, 30 to 40 degrees should be doable that way. Some heat will probably help, too.

Cheers
Steffen.

EDIT: Also: http://www.metalgeek.com/archives/2005/05/01/000047.php

leon · #9 22-02-2013, 08:17 PM

Yep sand will do the job nicely, especially with such a thin walled pipe.

Leon

LewisM · #10 22-02-2013, 08:53 PM

Wood's metal (Cerrosafe / Cerrobend etc) is another VERY effective way. It's an alloy of lead with a LOW melting pint (under 80° C by memory). You need just enough to fill the bend area and into the straight area again. Melt it, pour it in (bunging one end), let it solidify a little (but not completely cool, as it shrinks when cold - hence easy removal in most applications). Bend pipe. Heat again, pour it out.

DAF used to employ this technique for bending all the tubes in Beaufort airframe production in ww2 - gives an EXACT bend. They used to melt it merely in boiling water - no need for flames to vapourise the already poisonous lead and cadmium vapours.