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bending copper pipe

I would like to bend copper pipe rather then solder all those elbows.
The pipe is 1/2" (ie 5/8" outside diameter)
standard L straight pipe (not the soft rolls).
I have one of those springs for bending the pipe.
I tried to bend to a 6" diameter approx and the
pipe just rips apart.

What is the trick?
Should I try M thickness pipe?
Does this only work with the soft rools of pipe?



  • emma
    emma Member Posts: 1
    Replacing old cast iron(steam) radiator with baseboard

    I am looking for a replacement for an old, cast-iron radiator. I have found a baseboard but it does not have cover and it'll be hot. I need something with covers for kids.
  • hr
    hr Member Posts: 6,106
    I've got the bends

    Regular type L copper sticks work best. Type M kinda works but ripples a bit.

    I use a REMS Curvo powered bender. They also make a hand ratchet model.

    I also have there expander tool and tee puller to make all my fittings.

    The bracket on the wall is a primary loop and Munchkin boiler stand in one :)

    hot rod

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  • Dale
    Dale Member Posts: 1,317
    Conduit bender

    I use an electric wiring old conduit bender and it works if your radius isn't too tight. There is a hand version of what HR has, anyone who sells refrigerant tools carrys them.
  • Robert O'Connor_7
    Robert O'Connor_7 Member Posts: 688
    Your bent!

    Years ago we benefited from using bending tempered copper. I belive it only came in L or K (straight lenghts). Technically, according to certain codes (and a matter of x-tream interpretation??) its no longer allowed unless its use is accessible and allowed by the AHJ. I think thats why its not available any longer and many architects have made a point of specifically addressing it in the specs ( at least in the GREAT state of NJ, that is)...Robert O'Connor/NJ
  • Weezbo
    Weezbo Member Posts: 6,232
    Hot Rod..

    I like the swoopy 90's ,and i have been looking at the idea in my mind a long time now,so to day i am all into getting the electric curvo...only thing is,i happen to like 1" swoopys also ...will it work on 1 & 1/8 th ?
  • Ken_8
    Ken_8 Member Posts: 1,640
    If you only have a few to do

    simply heat up the pipe til dull red for about a 6" lenth where you want the bend and then use your spring bender.

    By heating the pipe you take the "temper" out of it and render it "soft" (annealed).

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  • hr
    hr Member Posts: 6,106

    Yes it will do 1-1/8" with the formers in the kit. REMS built me a 1-3/8" former to try, and it bends 1-1/4" copper just fine. A bit wider radius. That Munchkin rack is all 1-1/4" type L

    The 1-1/8" former will actually bend 3/4" schedule 40 steel pipe. So you can build some heavy duty mini-bike frames :)

    hot rod

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  • isn't conduit larger

    I saw those conduit benders. They are pretty cheap but I noticed that 1/2 steel conduit is slightly larger than 1/2 copper pipe. Does it matter that the pipe does not sit
    perfectly snugly in the form?

  • hmm

    my assumption was that bent copper should be more leak proof than sweated elbows. On the other hand now that I see how thin the walls become and then rip (when I tried to bend it) maybe I see why it might not be allowed anymore.
    Does anyone else know that its not allowed in there area?

  • bob young
    bob young Member Posts: 2,177
    pipe bending

    if you are ever on a u.s. navy ship you will see some very serious pipe bending techniques. in the shipyards we made templates out of 1/4" wire and bent the pipe with hydrolic benders. we used mostly couplings--very few fittings
  • hr
    hr Member Posts: 6,106
    When you think about it

    the copper ells we use every day start out a straight piece of pipe. They are formed that way in the factory with mandrel benders.

    Page 40 of the Copper Tube Handbook, published by the CDA has a section on bending it states "Copper tube properly bent will not collapse on the outside of the bend and will not buckle on the inside. Tests demonstrate that the bursting strength of a bent copper tube can actually be greater than it was before bending" www.copper.org

    The key here is proper bending! I think it needs that mandrel and follower to assure the tube does not egg out or kink. I don't believe a condiut bender will bend hard drawn copper with softening it as Ken mentioned.

    Cerro copper and others still offer several tempers of copper in straight and coil.

    All the tubes in AC condensors, evaporators, tube and shell HXers are bent from straight copper tube.

    As far as codes, yeah you best check in your area.

    When T-Drills first came into this market there was concern about the strength of that small pulled area. I see now T-Drill has all the approvals including the tough Federal and military specs met.

    Ever seen the machines that spin copper tube ends shut. I watched the machines at Sioux Chief spin those ends shut and with stand tremondous pressure tese without even soldering the ends! These are accepted by all the codes I have worked under in hydronic and plumbing applications.

    Copper is a very "form-able' material. Long may it live :)

    hot rod

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  • Steve Eayrs
    Steve Eayrs Member Posts: 424
    A related question???

    Does anyone know of a way to harden soft copper?? May sem like a odd question, but I have been wanting to experiment w/ soft copper and bend it, (maybe make a heated towel bar?), but would have to either harden it, or coat/dip it. Any ideas for hardening?

  • Paul Cooke
    Paul Cooke Member Posts: 181
    Hardening soft copper

    A 3rd generation plumber once told me that a piece of soft copper or a copper water flex connector will harden over time after it bounces around in the back of your van or truck for some time. Sounded strange to me, but there may be something to it.

    Has anyone else ever heard of this?

    Maybe you can build your towel bar and then vibrate it to harden it.
  • aha

    thats the project that I started this thread for.
    I want to build a heated towel rack.
    I think that you can never get the soft copper rolls
    to be perfectly straight so I wanted to
    use hard copper and bend it.
    I had in mind a serpentine pattern without all the ugly joints that you would get with elbows etc.


    well, something like that, with 8 loops.

  • Carl PE_2
    Carl PE_2 Member Posts: 42
    Work Hardening

    Same thing that happens to any metal when you bend it back and forth. Yes, it becomes harder, but more brittle.

    I'm skeptical that the towel bar really needs any hardening after it's built.

    So how were you going to finish it? clear-coat? chrome? bare?
  • John Shea
    John Shea Member Posts: 247
    Certainly not practical for the field, but

    couldn't you fill copper pipe with lead and bend it as if it were bar stock. This might provide a 'proper' bend if you're willing to go through the operation.
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443

    I just tried a piece of 1/2" L and a piece of 1/2" M, and got the same result. The M had ripples on the inner surface of the bend. I don't do much copper, but I have Ridgid ratchet benders for 5/8", 3/4" and 7/8" steel or stainless steel tubing. These things will bend heavy wall stuff, and cost a bundle new. I picked mine up used, because I don't use them enough to justify new. You can also get just ordinary lever benders for soft material like copper as well. I'm not sure about 7/8", but I know I've seen 5/8" and 3/4". 1/2" and down are the non-ratcheting style for any type of tubing.

    Just a note for the guys who are getting into bending tube - there's a scale on benders marked "45", "R" and "90". You always need to work with end to centre measurements on the tube. For example, if you need a piece 10" end to centre, align the mark on the pipe or tube to the "R" if the measured section is pointing out of the benders to your right. ("R" for "right".) If the measured section is pointing out to your left, move the line on the tube to be bent to the "90" mark. It doesn't matter for a 45*.
  • Weezbo
    Weezbo Member Posts: 6,232
    Place a cap on the end of soft Cu ,and it wont harden :)

    it embrittels itself in open air thats why it is wise to tape off the ends of underground K copper water lines that are left in the weather .... i think air makes the copper "dirty" over time...
  • Ed Lentz
    Ed Lentz Member Posts: 14
    John had a thought

    The lead might not be practical, but what about sand? Hard enough to keep its shape and loose enough to get out when you are done. I to want to make a towel bar somehow.

  • Dale
    Dale Member Posts: 1,317
    Sand works fine on steel

    My old father in law worked with German plumbers in Argentina after WWII, he said they packed iron pipes with sand heated with a torch and bent them whenever they needed a turn.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Why not try? You don't have much to loose.
  • newlove
    newlove Member Posts: 13
    Steve\"s question

    soft cu can be hardened by stretching 1 to 2% with
    a come a long.
  • Steve Eayrs
    Steve Eayrs Member Posts: 424
    Sounds interesting

    I think I will try it on a piece and then start the bending of things second, if possible. Will let you know what I find out.

This discussion has been closed.