Bending copper pipe - it creased

First go with my new pipe benders. Bent 22mm copper 90deg and when I looked at the finished job, there are a few creases in the inside of the radius.
Will this be a problem? The bend will be straight out of the DHW cylinder, if you see what I mean.
Should I have packed the pipe with sand?
Cheers!
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I think it has to crease. Where else would the "excess" copper go? I can't see it being a problem unless you are extremely concerned about the cosmetics of your airing cupboard pipework. I'd be interested to know whether packing with sand would work, but on the basis of my excess-copper theory I don't think it would make any difference.
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Davey wrote:

Maybe.
It should not hurt too much.

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That shouldn't happen. It might happen if the pipe has somehow work-hardened, in which case anneal it before bending. Do this by heating the area with a blowlamp and then letting it cool. It might happen if the former is the wrong size for the pipe (I presume it is a pipe bender designed for 22mm copper tube, and not, say, 25mm conduit?).

Only issue I could imagine would be if one of the creases is hiding a fracture. It will add to flow resistance too.

No. That's a different technique which I have used for larger pipes when I didn't have a proper pipe bender. Not necessary for 22mm tube with a proper bender.
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In an earlier contribution to this discussion,

Pipe bending machines do tend to crease the pipe a bit on the inside of the bend, A smear of grease on the pipe before bending it sometimes helps. As long as the pipe is round and uncreased on the bits where the fittings go, it shouldn't matter too much but - as others have said - it doesn't *look* too nice.
In the 'old' days (like 40 years ago, when I installed CH in my first house) copper tube had a larger wall thickness, and was probably a bit softer - and was easier to bend. I used bending springs which were inserted into the tube, which was then bent over my knee. This was a fun job when a bend was needed in the middle of a long section 'cos the spring disappeared inside the pipe and had to be pulled out with a piece of string after the deed was done. The trick was to bend the pipe slightly more than required, and then *unbend* it a bit. This freed up the spring so that it could be pulled out. Those were the days! <g>
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Roger Mills wrote:

Crumbs. Your experiences are taking me back to when I updated our first house in the 70s without affecting the exterior brickwork or appearance. Plumbing, of course imperial with lead bits. Electric: radial with one socket per room with added kettle flexes to additional sockets in crumbling breezeblock. Upsairs radial from a choc block from under the top stair.
Front garden tarmac'd by O'Casey above the DPC.
Them were the days.
I've still got the bending springs but don't recall using them for 27 years. :)
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In an earlier contribution to this discussion,

They won't fit any currently available tube because the wall thicknesses are now much less - quite apart from being metric!
Even in the 60's (or maybe 70's?) there was a new British Standard - with thinner walls - which meant that the old springs no longer fitted. Presumably something to do with the shortage/high price of copper at the time. [For the same reason, they also used stainless steel tube for a time - that was fun to work with!]
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Roger Mills wrote:

Fortunately, I've still got a fair few feet of pipe from that era in the garage loft for any alterations.
Don't fancy working with stainless!
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On 4 Sep,

There was also a "plated" steel tube in use around then arround the time of the Rhodesia (Zimbabwe) sanctions. I doubt if any is still extant. On average it lasted a couple of years.
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On Thu, 3 Sep 2009 19:17:35 +0100, Davey wrote:

You didn't get the pipe properly into the formers or used incorrect sized formers or formers without a bit of lubrication. Or you have a duff bender but I suspect "operator error". B-)

Depends how big the creases are. A photo is worth a thousand words... Little ones not a problem other than cosmetic and looking naff if you are a perfectionist.
You do realise that the vent pipe should rise vertically from the top of the cylinder don't you? If you put a horizontal section in the air released from the water as it is heated will collect in that pipe and be drawn to the taps when they are used. This of course this only applies to the connect at the top of the dome...

You shouldn't need to. A pipe bender should bend without creasing the inner side. I think this is done by just bending that face and stretching the outer one. The formers prevent the pipe deforming.
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Dave Liquorice wrote:

Probably was operator error :)

http://i30.tinypic.com/vpc87b.jpg
Yep, I know the vent pipe should rise, it's the whole reason I'm doing this plumbing. We have cavitaion issues with the shower (due to original plumbing being horizontal straight out of cylinder) so I'm fitting a surrey flange to prevent it happening. Air in the water to the taps is of little concern. I've put the bend in to eliminate an elbow joint as I thought it would be less resistive.
D
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No, that's very wrong.
A thought just occured to me -- you are using both parts of the former aren't you, i.e. both the curved part and the loose straight piece, with the pipe sandwiched between? If you tried bending the pipe without using the loose straight piece, I imagine you might end up with something like you have, because the pipe isn't accurately held between the former parts.
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On Thu, 3 Sep 2009 21:23:05 +0000 (UTC), Andrew Gabriel wrote:

But very similar to my first attempts on 22mm with a bender. B-) They look fairly broad and smooth crinkles so I doubt the integrity of the pipe is compromised.

That comes under "operator error". However without the outside former the roller just crushes the outside of the tube. I suspect the tube wasn't fully seated into the former on the bender or moved a little during the bending process.
As fred said you do need considerable force to bend 22mm and once you have started you really need to finish in one smooth action.
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Dave Liquorice wrote:

2nd go at it this morning provided better results:
http://i29.tinypic.com/6gwn7r.jpg
It is *much* harder work than I was expecting. Getting your weight on it right etc is difficult.
Thanks.
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In an earlier contribution to this discussion,

That looks better!

Assuming it's a hand-held machine, I aways find that it's better to clamp one arm into a Workmate - then you can concentrate on operating the other arm.
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On Fri, 4 Sep 2009 08:35:37 +0100, Davey wrote:

It is hard work but practice helps. You ought to try bending 22mm with a spring, almost impossible unless the bend is well away from the ends of the tube. That is why I bought a bender...
You could of course anneal the section of pipe you want to bend but I'm not sure that a small blow lamp could get the pipe evenly annealed and different "softness" might make things worse.
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Dave.




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Getting better.
A tight roller can cause problems.
Check that the small roller on the bender can turn.
May need to slacken bolt a little, and a small amount of lubrication (on roller bolt) would help.
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Now you mention it my pipe benders worked fine until my brother borrowed them.
I have just phoned him and asked if he tightened the rollers up when he borrowed them. Guess what, he did.
Adam
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On Fri, 04 Sep 2009 08:35:37 +0100, Davey wrote:

================================================ You sometimes need the first slight movement of the bending arm to push the pipe fully into the former - not necessary if the pipe is an easy fit in the former.
Cic.
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I've never had any crinkles in pipes I've bent (even my very first bends), and I've done loads of 15 and 22mm bends. I don't think my bender could create such a crinkled bend even if I wanted one.
I wonder if there are some wrong-sized formers out and about? My bender is a Record one. [Now there's a comment to be taken out of context;-)] Sadly Record (as was) no longer exist.
I see there were suggestions of lubricating the former, but I've never done that. What I have been careful of is to make sure the pipe and former don't have any dust on them. There was a warning about this in the instructions with mine (long since lost) that any sand/grit there could puncture the pipe, and end up embedded in the soft former surface where it could continue damaging further pipe bends and require replacement of the formers. I think a danger with using lubrication is that it might attract such contamination (besides being completely unnecessary IME). It may even be that the bending process is relying on friction with the inner former to perform some of the copper compression -- not sure on that one.

Probably not.

Looking at mine, the only way I could see for that to happen is if the outer former wasn't used, or the formers don't match the pipe diameter.

Again, that would be impossible with mine.

Yes. For 22mm, I try to arrange for one end of the bender to be pressing on the floor with my weight doing the bending on the other end, but if you have nearly 3m of tube sticking out and waving around, you need to be doing this in a large empty room or outdoors.
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