How do you bend copper?

[Lin]

About 35 years ago, i had a job in heat treating for about one month.  I didn't learn much then, and I've forgotten most of that.  As I remember it we tried to reach specific measurable hardness by adjusting the temperature of the furnace and the salt bath that was used for cooling.  I was told it was molten salt and was in the area of 700 degrees F.  The product was then cooled again in water, but I think that was just so it could be handled.  I was under the impression the using water as the primary cooling agent was too extreme a temperature change and that oil would be a better choice.  All that speculated upon, your purpose does not require any strict parameters.  I would guess that doing it the easiest way that completes the circuit would be adequate.

[Stan]

This has been an interesting discussion on mettalurgy and further proof that you can do anything with enough time and money. I stand by my original post 'it is not practical to bend rigid copper pipe'.

[gumpy]

This has been an interesting discussion on mettalurgy and further proof that you can do anything with enough time and money. I stand by my original post 'it is not practical to bend rigid copper pipe'.

That's why they make solderable fittings 

[DavidInWilmNC]

How well would rigid copper bend using one of the hydraulic tail pipe benders at a muffler shop?  I had some tail pipe bent for my generator installation.  I think several feet of 1½" pipe, two bends, and a couple expansions cost around $15-20.  This was at a smaller 'good ol' boy' type of shop.  I'm not sure how the copper would handle the bend, but perhaps filling it with sand first and then having it bent on one of those machines would work.

David

[boogiethecat]

Dave, the rigid copper won't bend at all in any bending machine or tube bender unless is annealed first.  Then it would bend fine in an exhaust tubing bender, as long as it is the right diameter for the tooling you'd be using.  If you try to bend hard copper as-is, it will break.  That's real point of this thread and the main reason annealing is necessary... "soft" isn't synonymous  with "easy"... "soft" in this context means that it's not so hard that bending it will break it...

[Paladin]

Ok, for anyone who cares.  I bent my 3/4" copper doing sort of a blend of ideas from here.

It's pretty rigid but did come coiled in a large coil so that's a good thing, odd though because it is 3/4 o.d. I filled the copper with sand and taped off both ends after tamping the sand down semi tightly. I looked around for something to bend it around and found that a curve on my wrought iron railing matched the desired curve fairly closely. I duct taped one end of the pipe along the curvature to hold it steady and then I fired up the little torch with propane, was going to use mapp but decided to try propane first, anyway I heated the section I wanted to bend including about 4" either way and slowly worked it into my bend. It did begin kinking ever so slightly so I just used a pair of slip joint pliers and worked it back into round. I think I got a little to hurried is why it began to kink a little. After I was done I blew out and rinsed the sand from the pipe.
Overall I think it'll work for the job. I got a sweeping 90 degree bend with no restrictions and no kinks.

Now I just gotta slip the pipes into the unions and I should be good to go.......unless I decide to do as Craig mentioned and add provisions for a loop in there for another heater inline.  Might need to add another pump for that though, worried about loss of flow.

-Dave   

[Lin]

If it came in a large coil, it is not rigid copper pipe.  It's good that it worked out, and there was no reason to use rigid pipe anyway. 

[Stan]

Lin is right. If it came in a coil it is soft copper and how hard it is to bend depends on the grade which is primarily the wall thickness. You may have got type K which is heavy wall and common because it is used for underground water service lines.

[Paladin]

Whatever it is it fits and I consider myself lucky to have found it, especially locally. Most of the people I talked to around here just shrugged when I asked them and had no clue. I was a bit worried I wouldn't find the right size although 3/4" isn't exactly hard to find, just 3/4" o.d.
Cost was about $5.50 per foot, a bit expensive but then copper is up.

[gumpy]

Now I just gotta slip the pipes into the unions and I should be good to go.......unless I decide to do as Craig mentioned and add provisions for a loop in there for another heater inline.  Might need to add another pump for that though, worried about loss of flow.

Put it in series with your defroster lines. Just tap into the supply line and run a loop out to behind the seat so you can add a small heater for the driver area and tie it back in where you cut it. No pump needed. Of course this will only work on when driving, unless you modify it and tie your house system into this line also. I was going to do that but decided against it when I looked for the lines in the tunnel area and decided I didn't want to try soldering in that cramped area with all the other mechanicals and such.