Bending copper tubing

I have some 3/8" copper tubing that I need to bend at a tight radius. Like

2". I have the spiral bender, and another hand held type, but can't find either. Next week, I gotta get organized. In the meantime what's the best way to bend it? I've heard of putting it full of sand. If I do that, do I bend it around something round, or just bend it slowly and cautiously?

Steve

Reply to
Steve B
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I have a similiar dilema. Refrigeration units that store salads and foods with high acid content, eat up the condensate line (condenser high side line that dissipates the drain water in a pan). The radius is like you say about two inches and all the benders I can find are larger radius than that. Oh and I need 180 degree bends to get as much surface area as possible. If I lose a complete pass, due to space, it will not get rid of the water and we now have a water leak to worry about. Harbor Freight has one that works........but mine leaves a pretty good scar on the tubing on a 180 degree bend, and all the others on the shelf look identical with no difference in quality. It seems the guide is too loose and crimps the tubing, For the money it is not bad. I am half tempted to fashion a bender out of some heavy wood using a 3/8" core box bit and woodworking router (cutting the flutes as deep as possible). Another posibility is to stack large flat washers between two flat pieces of steel and bend away. This may require dissasembly for each bend but get you out of a bind. Good luck and tell me what you came up with. Lyndell

----- Original Message ----- From: "Steve B" Newsgroups: rec.crafts.metalworking Sent: Saturday, October 08, 2011 9:35 PM Subject: Bending copper tubing

Reply to
Lyndell Thompson

I have tried the sand method and it did not work well for me. The classic way to make the sharp bends on trumpets and such is to fill the pipe with melted pitch and let cool. Another method is to fill with a water-detergent mixture and freeze it. The detergent keeps the ice from becoming hard enough to burst the pipe. Don't ask me what the right detergent concentration might be.

Reply to
anorton

"Lyndell Thompson" wrote in message news:3O6dnS6lLPXSkQzTnZ2dnUVZ snipped-for-privacy@insightbb.com...

I have a similiar dilema. Refrigeration units that store salads and foods with high acid content, eat up the condensate line (condenser high side line that dissipates the drain water in a pan). The radius is like you say about two inches and all the benders I can find are larger radius than that. Oh and I need 180 degree bends to get as much surface area as possible. If I lose a complete pass, due to space, it will not get rid of the water and we now have a water leak to worry about. Harbor Freight has one that works........but mine leaves a pretty good scar on the tubing on a 180 degree bend, and all the others on the shelf look identical with no difference in quality. It seems the guide is too loose and crimps the tubing, For the money it is not bad. I am half tempted to fashion a bender out of some heavy wood using a 3/8" core box bit and woodworking router (cutting the flutes as deep as possible). Another posibility is to stack large flat washers between two flat pieces of steel and bend away. This may require dissasembly for each bend but get you out of a bind. Good luck and tell me what you came up with. Lyndell

----- Original Message ----- From: "Steve B" Newsgroups: rec.crafts.metalworking Sent: Saturday, October 08, 2011 9:35 PM Subject: Bending copper tubing

I have bent 3/8" and 1/4" copper tube to some tight radii by wrapping the area to be bent closely with small copper wire and bending by hand. Carefully.

Garrett Fulton

Reply to
Garrett Fulton

probably find it in this

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Reply to
Steve W.

I bent some 10mm copper tube recently into a tighter radius and used some nylon rod I had about inside the tube. I do have Cerrobend but didn't want to use it at the time. The nylon was just slightly smaller than the ID of the tube and after bending I could grip the rod in a vise and twist the rod out without too much trouble, the subsequent bends I lubricated the nylon which eased removal.

Reply to
David Billington

Good idea, I will try it. I could leave the wire on it for extra protection and wear resistance. 14 guage solid wire?

Reply to
Lyndell Thompson

Amateur radio types used to bend copper tubing by filling it with sand to keep it from collapsing while bending.

Reply to
Michael A. Terrell

Steel wire will work better. Have you ever seen "spring benders"?

They're a little bit of a chore to get back off a tight bend, but they work very well. I have a nice full set in my refrigeration kit. Just expect to spend longer getting the bender back off the tubing than it took to put it on and make the bend. Spin the bender in a direction to UNwind the spring, and it will slowly screw itself off the tubing.

LLoyd

Reply to
Lloyd E. Sponenburgh

How about filling with melted paraffin wax and then just melt it out after bending?

Reply to
clare

You may want to make sure the tubing is fully annealed first too.

Reply to
clare

Or secure one end with lightly applied visegrips and unwind the spring enough to pull it right off. They're usually a PITA to use, though, and you can't use them on complete tubes, with flared connectors already installed. I have several handheld benders for those.

-- Never trouble another for what you can do for yourself. -- Thomas Jefferson

Reply to
Larry Jaques

I don't think that would be strong enough, I think it will just extrude and the pipe will flatten. Molten lead is another option; there used to be low melting point alloys specially for this (Cerrobend, in the UK). Non-trade name is Woods Metal.

Reply to
Newshound

Larry Jaques fired this volley in news: snipped-for-privacy@4ax.com:

So, don't flare the "U"s until you have them bent. This is a homebrew.

LLoyd

Reply to
Lloyd E. Sponenburgh

"open coil" benders can be used on already flared tubes, you justunwind the spring off the tube. Closed end coils CAN be used this way as well, but a lot harder to get the end started unwinding without damaging the spring.

Reply to
clare

works just fine if you start with tube a bit longer than you need, fill 1t 100", and crimp both ends of the tube shut before bending. Also works best if the tube is at temp where the wax is still "Plastic" - not totally hard.

Full of grease works too, but it is a lot harder to clean out. Tallow would likely work too, and it never gets as hard as Paraffin. - again, perhaps not as easy to totally clean out??

Reply to
clare

Good idea, I will try it. I could leave the wire on it for extra protection and wear resistance. 14 guage solid wire?

I always used .040 stainless lockwire. Don't see why the 14 guage copper wouldn't work, but haven't tried it.

Garrett Fulton

Reply to
Garrett Fulton

I saw the program where they were making trombones, they used the soap and water mixture there. I think sand has to be finer stuff than playground sand, probably more like some grades of molding sand. The classic production method for small tubing is Cerrobend as a filler, melts in hot water. Wall thickness will have a lot to do with how sharp a bend can be made, tubing is available in a lot of different wall thicknesses. And I'd definitely run the stuff through a torch to anneal it to dead soft before starting anything. Doesn't need to be red heat, just enough to discolor it. It DOES make a difference. Will probably take a number of tries before you get the right combination.

Stan

Reply to
stans4

Seems like a Delrin rod that was cut to 1/2 diameter with a cutoff tool - every 1/2" or more or less - would provide some give in a bend but would hold diameter. Pulling out from each end might be logical - perhaps breaking a joint and freeing the curvy bend. The smaller diameter is a temper fuse :-)

Mart> Steve B wrote:

Reply to
Martin Eastburn

I did some research on this question some months back when I wanted to wind copper and aluminum coils to power a "putt-putt" ("pop-pop") boat. "Spring coil" benders/winders are helpful up to a point (about

270deg), but with really tight turns it's hard to remove the spring coil from the finished tubing coil.

Through some oversight I actually saved the links to a couple of sources that I found useful:

Home Distiller: How to wind a perfect coil condenser

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MetalGeek: How to Bend Tubing and Pipe by Hand
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Hope these are helpful.

Frank McKenney

Reply to
Frnak McKenney

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