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metalmagpie
04-01-2012, 11:46 AM
I want to use a Ridgid tubing bender to bend M type 1/2" copper pipe. I'm told to do this correctly the pipe will have to be annealed, which is easy, just heat it up to a barely red and let cool. After I make my bend, I don't want dead soft copper anymore. I was wondering if there's some mechanical way to re-harden the copper, maybe shot peening or vibration?

Reason to bend instead of soldering on fittings is I don't want to buy all those fittings and once shined back up the bend should look better. Of course, I can always buy fittings and sweat them on.

All for an air distribution system. And please let's not get into the copper versus black pipe versus PVC versus PEX again.

And no, this isn't an April Fool's troll.

metalmagpie

loose nut
04-01-2012, 11:53 AM
The act of bending the copper will make the copper harder, it's called work hardening. I don't know if that will be enough for your needs.

Evan
04-01-2012, 11:54 AM
Bending it, even just once will harden it. Limit the annealed area to the actual bend area by wrapping the pipe with wet towelling at the limits of the bend while you heat it. I used to use wet asbestos cloth but somebody decided it was dangerous even though I never ate any.

Type M is not recommended for pressure applications in soft temper. It is also much more likely to fail from internal corrosion. I would use type L.



Type M copper pipe
Type M copper pipe and tubing is commonly used in residential plumbing because it has thin walls and can be produced and sold at a much lower cost. For water distribution longevity type M is not recommended. Type M copper is also better for heating applications because of the thin wall thickness. Type M is identified with RED markings along the pipe.

Hard temper type M plumbing applications include:

Above ground water distribution
Above ground drainage systems
Soft temper type M shall not be used in plumbing systems.

http://www.plumbinghelp.ca/articles_types_of_copper_pipe.php

lakeside53
04-01-2012, 12:01 PM
Even with a bend it's not even close to the same hardness as the hard drawn pipe. I've bent plenty of soft copper tube and it's still "soft". Also overheated my share of pipe - it's never the same :mad:

For air, use Type L pipe. For soft copper, Use type L or K. Do they even sell soft "M"?

I find flexible more of pain than fittings, and fitting can look beautiful when cleaned up!

Evan
04-01-2012, 12:04 PM
In most jurisdictions it is a code violation to use type M for air systems.

lakeside53
04-01-2012, 12:06 PM
It is here.

So..MM why do you want it hardened again? If it's not supporting any weight and secured back to structure it will be fine. I wonder if the L pipe is derated when annealed?

chipmaker4130
04-01-2012, 02:23 PM
Have you looked at the 'long turn' elbows and other fittings used in refridgeration systems? They might give you the look you want without the hassel.

metalmagpie
04-01-2012, 02:53 PM
OK I meant type L.

No I haven't looked at refrigeration fittings. Where does one go to look at such?

oldtiffie
04-01-2012, 08:03 PM
I want to use a Ridgid tubing bender to bend M type 1/2" copper pipe. I'm told to do this correctly the pipe will have to be annealed, which is easy, just heat it up to a barely red and let cool. After I make my bend, I don't want dead soft copper anymore. I was wondering if there's some mechanical way to re-harden the copper, maybe shot peening or vibration?

Reason to bend instead of soldering on fittings is I don't want to buy all those fittings and once shined back up the bend should look better. Of course, I can always buy fittings and sweat them on.

All for an air distribution system. And please let's not get into the copper versus black pipe versus PVC versus PEX again.

And no, this isn't an April Fool's troll.

metalmagpie


Check out a Plumbers "bending (coil) spring". It slides onto and is a neat fit to the copper pipe where the bend is to be. It works well with or without the "Rigid" bender - preferably on annealrd (softened) copper pipe but will work on some grades of harder (less soft) copper pipe with care.

It might even work with the spring in conjunction with the Rigid bender.

The coil supports the pipe and stops or reduces the normal deforming.

lakeside53
04-01-2012, 08:07 PM
OK I meant type L.

No I haven't looked at refrigeration fittings. Where does one go to look at such?


My place :D I have U and ell... but.. they are still "solder". Don't really save you anything,

Evan
04-01-2012, 10:29 PM
To bend hardened copper fill it with salt, then bend. That will prevent kinking.

oldtiffie
04-02-2012, 04:56 AM
Probaly so but that salt will need to be dead dry and well packed/tamped down.

chipmaker4130
04-02-2012, 11:14 AM
I get the refer fittings at one of the local HVAC shops. It is true they are sweat fittings, but you're going to have some of those anyway at the straight joints, and these are formed at a radius similar to what a typical pipe bender would produce.

Evan
04-02-2012, 03:23 PM
Probaly so but that salt will need to be dead dry and well packed/tamped down.

Dry is obvious. You can't tamp salt which is why it works. The crystals are cubic and freeze in place under any pressure.