How to avoid copper pipe crinkling during bending

[waltwales]

Hi,
i have noticed many articles on various forums over the years discussing the extremely annoying occurance of crinkling when bending copper pipe with a pipe bender.
i have a really cheep 15 + 22mm pipe bender that would sometimes make perfect bends and at other times would make crinkled ones. i tried a steel shim on top of the aluminium former to advance the bend fulcrum with mixed results.
Eventually i found what appears to be the answer and that is keeping a constant pressure whiles bending: relax the force on the arms for a second [ie stop and start] whilest bending and you'll end up with crinkles in the copper.
However when you need to stop the bend to check the angle KEEP THE BENDER ARMS UNDER PRESSURE without further actuating the bend [It can help to rest one of the bender arms on the bench/floor to free a hand to do the measuring]. If you need to take the bend further increase the pressure again.
It takes a while to get your head around but eventually you'll get the knack of it and you'll throw even, smooth bends everytime

cheers, waltwales

 

[onecog]

A lot of it is because of the crap copper used nowadays.
You could almost bend the softer copper of years ago without a spring/bender.

 

[waltwales]

A lot of it is because of the crap copper used nowadays.
You could almost bend the softer copper of years ago without a spring/bender.

hi onecog,
i've used the technique above on both ancient and brand new copper pipe, both 'as is' and annealed with the same results. The older pipe is certainly a lot thicker walled but again if pressure is relaxed during a bend it will also tend to kink.

cheers, walt wales

 

[Blagard]

It sounds like you have a crap bender.

I have no problem re-inserting a bent pipe and tweaking it around a bit further.

Only once recently have I had a pipe wrinkle and I put that down to a crap piece of pipe and discarded it.

For what it's worth many years ago I worked on the staff of a decent size plumbing outfit (employed about 40 plumbers). It was very rare to have problems with pipes although I do recall one leak arising from a pinhole size hole in a bad bit of pipe. So rare that the supervisor brought me the pipe to see!

 

[waltwales]

It sounds like you have a crap bender.

I have no problem re-inserting a bent pipe and tweaking it around a bit further.

Only once recently have I had a pipe wrinkle and I put that down to a crap piece of pipe and discarded it.

For what it's worth many years ago I worked on the staff of a decent size plumbing outfit (employed about 40 plumbers). It was very rare to have problems with pipes although I do recall one leak arising from a pinhole size hole in a bad bit of pipe. So rare that the supervisor brought me the pipe to see!

Hi Blagard,
yep the bender i inherited was a really cheep version and only used when as i was in a fix hence the original post. That being said i have spoken to mates who have Rothenberg benders who say they also get kinks on occassion. Applying a constant presure until the bend is finsished really does prevent wrinkling.

cheers walt wales

 

[Norcon]

You want an A frame bender which will apply adjustable force to the slide.
There's a knack in knowing the right force though.

A good pipe fitter will adjust as he bends.

 

[swbjackson]

The crinckling is known as throating and will happen with a rubbish bender or with a poorly maintained bender. It is also a lot more likely to happen with continental copper tube which seems to be a lot harder than the normal half hard copper manufactured in this country.

The main cause with a good bender is a dirty guide or former although I have seen the same happen when the wheel seized on a workmates bender.

 

[villageclown]

I dont know much, but am yet to 'throat' a pipe while bending it.

I strongly believe the wrinkling of the pipe is due to poor quality pipes and poor quality benders (as have been pointed out).
You get whart you pay for

 

[mcmoby69]

try rubbing some wire wool where the tube sits in the former and the guide until it shines.

 

[mickthegas]

Dirty former