[TheForge] Pipe bending

[Paul]

  It seems that what you were attempting to do was what we call in the 
trades a "wrinkle bend". It is not that common anymore, as it does 
weaken the pipe and introduce stresses that are not a good idea in 
pressure piping. The part where your description varied from what we 
actually did was that you were 'necking' the pipe down and then trying 
to upset it.

The process that we used was as follows:
    Heat the pipe about 240 degrees radially on the inside of the bend
   Bend the pipe using the cold 120 degrees of the pipe as a hinge and 
collapse the hot side. It will from a pucker in the pipe on the hot side 
if you bend it far enough.
   In an extreme bend the cooler areas of  the hot side of the pipe will 
actually touch...if you  want a rather tight radius, the raised 'pucker' 
can be cut off and the pipe welded to hide the excised piece of pipe.
It is important that you heat the pucker side quickly and do not allow 
the heat to creep to the 'hinge' side. Cool the pipe when you get to the 
degree of bend that you want and before starting the next wrinkle.
You can also leave the pucker if it is not unpleasant to look at and if 
you don't carry the bend to an extreme.

The next wrinkle is spaced down the pipe and the process is repeated.
Once you make a test bend, you can figger out bend spacing and degree.
I will also add from practical experience that you should use a rose bud 
tip to heat the pipe quickly and prevent the heat from spreading to far 
axially along the bend side. This will result in a neat little bend.
If you are using schd 40 pipe with a seam, place the seam on the inside 
of the bend as it will split on the outside.
Practice and trial pieces are a real good idea...

see for some pics and text...

http://www.tpub.com/steelworker2/42.htm


    I need to bend a length of 1 1/4" pipe about 45 degrees as part of a
    hand railing. Any ideas on how to best do that without access to a
    Hossfeld
    or other non-crimping process?

    In the past I necked down and then upset (to create a kind of
    bubbley effect) and then bent there. It worked and looked
    interesting. This time
    when I tried it, and after doing a bunch of other work to the pipe,
    the necked down part was too tired and a tear started which couldn't be
    salvaged (I tried).

    Thanks for any appropriate info.

_
_

    Dan A.

-- 

Paul
WB9HCO
My Grandfather WAS a blacksmith...
and it didn't do me one damn bit of good.
All opinions are the personal beliefs of the author, and are based on decades of experience... so use your best judgement, I'm just a lowly crafstman.
  "The difference between genius and stupidity is that genius has its limits." -Albert Einstein
"Life is hard...it's harder if you're stupid" John Wayne - Sands of Iwo Jima