Bending type M rigid copper

Discussion in 'Shower & Bathtub Forum & Blog' started by Mr. Overkill, Jul 15, 2005.

  1. Hi all, I hope you can help.

    CX from John Bridge forum sent me over here.
    I have 2 threads going over there:

    I've been construction phase of building a house for over a year now doing alot of the work myself.

    I'm back on the shower project after taking a sabbatical to accomplish a few other projects around the house like changing toilet drain locations and squaring up doors and windows from drying lumber and cement settling.

    I am now tackling the rough-in plumbing for the steam shower and ran into a few problems with the routing of the copper lines and stud warping.

    1st the stud problem:
    I have already replaced 3 studs that were the worst off (warping inwards or outwards of the shower) and blocked another 2 that were warping side to side. The 3 studs I replaced are already warping after only being in for 3 weeks. I am now officially sick of fixing and replacing studs. The only studs I could get around my area are either already warped or are so heavy with moisture, they warp very quickly in the Pahrump climate (today it was 110 degrees with only 4% humidity) I could almost watch the wood drying out and twisting in front of me .

    Framing questions:
    1) How much of an outward warp will I be able to compensate for during the tiling stage (I know that a board warping inward can be planed)?
    2) Seeing on how getting straight lumber around here is next to impossible, if a board is to warped for compensation, should I go with the cut and shim solution for straightening?
    3) Can a layer of mud be applied to the Durock to get my even straight walls?
    4a) Or should I just forget the Durock plan and attempt a mud shower to get my straight walls?
    4b) If I go with the mud shower how much thicker is a mud wall compared to ½†Durock? (to adjust my valves appropriately)

    2nd the pipe routing problem:
    My shower will have 2 shower heads, 4 body sprays, 1 rain from ceiling, a hand shower, a steam head, and 2 valves with selectors all on 2 walls. I am using ½†rigid copper pipe for the water lines and routing is becoming a problem since there is so much going on inside the walls. Some of the pipes being on the same plane are in the way routing another.

    Pluming question:
    1) To get away from using to many 45’s is there a trick to bending rigid copper just enough to get around another pipe without kinking it?
    (I’m not particularly fond of using the thinwall pipe, I want my shower to last as long as I’m in the house)

    Thanks in advance for advice -
    I'm in a rush to finish the rough-in to get my inspection and move on the next stage, I am already 2 ½ months over schedule and my better half is turning into something other than better.

  2. A German Elbow

    Why cant you just use a roll of soft copper type L???

    Now bend hard copper

    in the mid west bending the pipe to make a

    45 degree has been called makeing a "german elbow"

    I have actually seen it done with 1/2 or 3/4 in GALVANIZED pipe
    by old timers that needed to cheat just a smidgen.....

    I remember my grandfather takeing a piece of 3/4 galv pipe and
    heating it up to bright red, then beating it against a telephone pole!! LOL

    I suppose the galvanized pipe is still working ok
    (43+ years have passed)

    So its not a big deal to bend the copper,

    try it first to see what I am talking about

    first you evenely heat the pipe along where you want to make the bend

    to cherry red probably along about a 6 inch area....

    this basically softens the pipe,
    then you let it cool down slowly then just hand bend it to a 45
    but be careful not to kink it.... its best to wear gloves.

    I have done it for years when I needd to cheat
    a little with never any problems at all.

    its no big deal

    Now the shower you are installing sounds like something
    out of my worse nightmare.....

    if everythignd is warping this badly have you considered

    just installing some acrylic imitation marble walls

    or somethiing that might be more forgiveing???

    that is a mess that is going to come back and bite you

    in the ass if their is a possiblinty of warping after you are done...

    good luck
    Last edited: Jul 15, 2005
  3. Thanks for the reply Mark I really appreciate it.

    I wanted to use the type M pipe for the added protection of the thick wall copper.

    I already tried using a conduit bender and that kinked it within a 10 degree bend, I like the heating idea. :D

    I will try heating and bending tommarow and let you know how it went.

    I don't know if the warping studs are considered that bad but it is warping anywhere from 1/8" to 1/4" at center of stud which will be noticable after tile is set. And yes warping after the job is done dose scare me.

    I haven't seen the acrylic imitation marble your talking about do you have a link to that.
    My shower is 4'6" x 6' with a 8'4" ceiling sloped down to 7'2"

    Thanks again for your help. :)

  4. RioHyde

    RioHyde Plumber

    Cincinnati, Ohio
    Type L has a thicker wall than type M copper. I've done the same thing that Mark described in bending rigid copper. Works just fine though it might be easier for you to use type L soft copper for the installation.
  5. captwally

    captwally New Member

    What are you installing, a shower or a Human Car Wash? I'm joking of course, but bending ridgid copper scares me. I'd either use flexible copper from the POC to all the outlets in your shower, or high pressure flexible poly pipe with compression fittings. Contrary to anything you may hear, there is nothing wrong with using compression fittings, no matter WHERE they are, as long as they are properly installed. Check out the thread discussion here under "General."

    You'll read everyone's pros and cons. That's why this is a great place.
    Last edited: Jul 16, 2005
  6. plumguy

    plumguy New Member

    I have never bent pipe, but have used plenty of soft roll that I thought was type K.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    Back to the bending of galvanized pipe. EVERY hand vise has a mandrel on the top that is used for bending up to 1" pipe. Bending type "M" copper is a bad idea even if it is heated. The walls are too thin so you induce stresses into the material, even if you do make the bend without kinking.
  8. jimbo

    jimbo Plumber

    San Diego
    1. With regard to the comments about compression fittings: we have had great discussions here about how wonderful and reliable they are for stop valves and supply tubes. The fact remains that codes usually do not allow use in a non-exposed area.

    2.. Most places, you CAN buy kiln-dried studs. The green ones may continue to warp over time in your situation, which would be bad for the tile job. Even HD sells dry studs, so I sugest you bop over to Henderson and get those. Then you should be able to install a plumb and flush plane for the backer.
  9. WOW!! Thanks for all the replies everyone.

    I appreciate all the replies. :D

    Well I spent the whole day working on the house today on other projects after trying the heating and bending idea. It worked really well but ended up not using it anyway. After it cooled down I was still able to bend the pipe almost as easily as when it was hot. The pipe seemed to soft for me to be confident using it in my wall. I guess I'll use the type L copper and call it a day.

    Besides after looking inside the test peice of pipe there was flaky stuff on the interior wall that did not look kosher to me, so I cut it open to get a better look.

    I took a couple of pics for all to see. Maybe someone else can learn from my experience.

    The 1st pic is the fished pipe that looked good but to soft for my taste.
    The 2nd pic is a look inside at the flaky stuff.
    The 3rd pic is a look inside after I wiped the flaky stuff off with my finger.


    Attached Files:

  10. RioHyde

    RioHyde Plumber

    Cincinnati, Ohio
    The flakes you see are caused due to the fact that oxygen was in the line while it was being heated to the point of being cherry red. Just something I hadnt thought to mention. If the line had been purged with nitrogen then heated the flaking wouldnt have happened.

    I do believe you'll be in better shape either using the soft copper or soldering in two 45s to make the offset. If you do go the soft copper route just take care not to kink it and you'll be fine.

    Good luck!
  11. I have a little extra time on my hands while my wife is cooking dinner so thought I'd give a more personal reply to all.

    Liked your idea but don't think its for me, thank you anyway. :)

    I was under the impression that Type L was thinner than Type M because of the rigidity (if thats how you spell that). I guess I was wrong again. :eek:
    That is the whole reason I wanted to use Type M and cheat the bend. But if Type L is thicker, I feel more safe using it. Thanks

    My wife says the same thing about the car wash. I like alot of hot water, and the spa shower will up the resale value of the home -its the new in thing-. As far as compression fitting are concerned, I have no problem with them, my whole house is plumbed with PEX an manna block. I just didn't want to put to many in the shower itself because the compression fittings actually restrict the flow alittle and with so many shower heads I'll be pushing the envelope on water pressure as it is. Thats another reason I didn't want to use extra 45's and bend the pipe instead. And yes, I like this site as much as John Bridges site. Thanks

    I have never heard of Type K copper. I thought the type on a roll was Type L.
    If anyone can clarify it would be appreciated.

    As my previous post stated after the pipe cooled down it was still soft. So your rite on that one. Thanks

    I would go to HD but for me its about 75 miles to the closest one up and over the mountain. (Henderson is actually farther for me) I have a CV joint on my car that has be making noise when I accelerate around a corner and don't have the time or money to tackle that until I move in the new house. Not worth puting extra miles on the car that I can get away from. I will just shim before I put up the Durock. Thanks

  12. Thanks RioHyde-

    Is the soldering process on the soft stuff the same as the rigid?

  13. Yes. It is the same as hard copper.
  14. jimbo

    jimbo Plumber

    San Diego
    The 3 common types of copper THICKNESS are K, (thickest wall), L (medium) and M ( thinnest).

    Copper TUBING is commonly available as type HARD ( usually referred to as copper pipe, the rigid 10 foot sticks) and type SOFT ( the rolls)

    When you heat the tubing to bend it, you anneal the hard back to soft. The other characteristics are not changed.
  15. Thanks RUGGED and jimbo,

    I'll go buy some soft copper today and start soldering.

  16. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    After heating and bending the tubing you would have had to reheat and oil quench it to restore its temper. "K" and "L" both come in rigid and soft tempers. "M" only comes in hard temper. To avoid the internal oxidation you have to have the tubing filled with an inert gas, nitrogen being the most common one used.
  17. bending pipe

    What are you guys planning on putting through
    these pipes anyway, nerve gas???

    I have made "german elbows" on type m copper pipe for years

    and years used in lots of situations under full pressure

    with absolutley no problems.. never a single one

    I suppose maybe I made a mistake about how hot to
    get the pipe, after you have gone up and down the pipe with
    your tourch, when it just starts to turn red, STOP

    you are not supposed to melt a hole through it.

    all you are doing is softening the copper , if you feel more

    comfortable , use type L , it is thicker and will bend just

    about the same way....
  18. Well the town is out of soft copper so I started soldering the other pieces today. It started off bad when the solder wouldn't seep into the joint. I figurred it was a flux problem since its been in the hot van for about 2 weeks so went to get some fresh stuff. That did the trick. By the time I dismantled my valves and got everything sanded fluxed and straight and level on the cement I didn't get much soldering done today. I only soldered 22 joints today. The sanding and deburing took longer than expected and my fingers are killing me from the inside sanding, I guess I should have invested in wire brushes instead.

    1) Does tempering make the pipe (or I guess tube is the proper name) less likely to pit and spring a leak over time?
    2) Which type of tubing is considered the most reliable (soft, hard, K, L, or M)
    I've never seen or heard of K.

    when I heated the copper it was next to impossible to distinguish when it actually turned red since the copper is almost a red anyway. Is there a trick to now when it is actually red with the naked eye.

  19. Two more questions

    This is the 1st time I ever actually soldered in vavles and didn't realize how long it took to heat up the valve before the solder would melt, even though I was using map gas. After soldering all the valve connections I was sort of in the heating mode and might have over heated a few tube to elbow fittings. Also since I was sweating my connections on the concrete one of my "T" fittings got out of position and it turned up alittle, So I reheated it and twisted it strait.

    1) Will heating a sweat connection more than is neaded create a bad solder joint.
    2) Was reheating a sweat connection and twisting it a no-no? should I have taken the whole assembly apart and start over?

    Those 2 thing have been bothering me all night, I don't want any leaks when I do the water test. Its always harder to resolder after everything is wet. Although just to redo that 1 "T" I would have to redo atleast 2 other fitting also. What do you think?

    Thanks in advance for your advice.

  20. sorry, another question to add to the other 4

    I could not find a drop L in the T configuration to make my body spay pressure loop so I T'd off to regular drop L's.
    Is this configuration OK, or am I crating more pressure loss with to many corner for water to go around?
    If so I can order the proper ones online, just didn't want to wait for arival.

    Thanks for advice,

    Attached Files:

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