Pipe bending

Oct 05, 2014 40 Replies

I'm attempting to bend a 22mm copper pipe with a (cheap) pipe bender of the type

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The pipe is few years old but I'm getting ripples on the underside of the bend.



Bottom of bend and top of bend photos

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What is likely to be the problem? Pipe? Bending tool? Operator? And is there a easy fix for future bends.



inadequate knowledge of how to do the job

you're supposed to use one of these:

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tim

I'd have said you use a spring *OR* a bender rather than both, if that's what you're suggesting.

Anneal the tube first to soften it?

Have you tried to bend 22 mm pipe with an internal spring? Might work with soft copper but not the normal half hard stuff.

Or you suggesting putting the spring in then using the bender? Getting the spring out might be fun.

As for the OP. Lightly grease/lubricate all parts that touch the tube to be bent. Make sure that the tube is fully seated into the groove on the tool. Use the seperate bar part, groove to the pipe, between the tools roller and tube.

Not with a pipe bending machine you're not :)

It points to the machine being poor quality. My not-exactly-expensive bender does not wrinkle the pipe - well, not in any noticeable way...

Are you sure it's 22mm pipe, and not 3/4"?

Try annealing the copper along the area of the bend first. It may have work-hardened over time in storage, particularly if it has been subject to vibration.

To anneal copper, heat it up with a blowlamp (or over a gas stove burner), and then let it cool (no need to quench it).

And to follow-up the other answer, no you do not put a bending spring inside when using a proper pipe bender.

Update - poor quality of tool. Temporarily I've tightened the the bolt that holds most of the tool together as much as I dare to remove some/most of the slop and I wedged in a nail between the half moon and frame to stop it from moving.

The alignment between pieces of tool still leaves room for improvement.

I've now done a perfect 90 degree bend on the same pipe without it rippling.

Sods law says I cannot find my tin of washers which would fit the screw holding the assembly together and a few weeks ago I had a clear-out and chucked some metal pieces which would have been ideal as a shim behind the half moon piece.

alan_m wrote

Is the copper pipe moving/slipping when you bend it ? Pull the bend in one move, not a series of jerks.

Or like a friend did, filly it with sand first!

Brian

Sloppy or worn pipe bender by the looks of it.

You are having a laugh I take it? (or just enjoy watching someone rip their knee caps off!)

Are you sure it's not 3/4"pipe?

Some more recent pipe is in "half hard" condition and is not intended for bending. (It has a very thin wall)

Getting the spring out is easy. Bend the pipe a bit "too far" and then ""straigthten is slightly (only a couple of degrees needed) and the spring will come out easy.

Yep, a bit of DIY modification and it works OK. A thin washer removed all of the slop and a metal shim made from two disposable knife blades glued to the former piece (and then ground to remove sharp edges) ensured that it actually fitted more squarely/closely into its mate.

When did they last sell 3/4 copper pipe in the sheds?

That's not sod's law, it's feckless, profligate, wanton foolishness. Never, EVER throw anything away. You never know, it might come in, and even if it doesn't you'll have the continuing pleasure of ownership.

I learnt this principle at my father's knee, and I can look at our shelves and see items such as a box of Art Deco Bakelite radio knobs, a collection of Wylex mains plugs, a spokeshave without a blade, a brand new oil filter for a 1948 Morris Commercial, and a flat iron with a chunk out of it.

Bill

I never throw away useless junk!

My father, when he was alive, always kept things claiming they would come in useful one day. After his death, and my mother wanted to move house, we had to hire a large skip to get rid of all this useful stuff - nothing was kept.

I'm trying not to keep anything I haven't used/seen for a couple of years, especially old electronic equipment. It may have been relatively expensive when I purchased it when when I upgrade its usually worth next to nothing and difficult to even give away.

3/5 are probably saleable

NT

I've used dry sand to bend 28mm copper pipe, but that's because I don't have a 28mm pipe bender. Dry sand or liquid lead sealed in were the traditional ways to bend large copper tube.

More bollocks from harry.

*all* commonly available pipe is half hard these days, and has been so for many years.

Its perfectly suited to bending with a proper bender. The thing you can't do so easily with half hard pipe is use a bending spring.

That does not stop it bending.

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