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[patrick_g]

The HF hydraulic bender with 5-6 mandrels is a bargain and does a lot if you are careful. The "pack it with sand" trick helps a lot for greater bend angles and thinner walls. Nothing wrong with the low melting point metal but sand is far cheaper and gives about the same results. In larger diameters it taks a LOT of metal and is a chore to bend.

Pat

 

[Egon]

radius would be about 16 feet

For do it yourself you may have to make a wooden/?? form to bend the pipe too. If the pipe is water filled and pressurized it stops the kinks from forming.

 

[patrick_g]

The HF benders do not REQUIRE you to bend to any particular minimum. You can bend 0.001 degree if you wish. A series of mild bends made one after another fairly close together (regular intervals) will allow you to make a circle if you want (close approximation). You would need to have a place to mount the bender (elevated above the floor) to give clearance for the bent tube. Doing it in sections as mentioned would make it easier. I suppose you could lay the bender on its side and have the bent tube in the horizontal plane.

You could use a piece of string and some chalk to draw a circle of the right radius on the floor. Use it to gauge your progress.

Pat

 

[IslandTractor]

Patrick and Egon, Thanks very much. I was unsure if you could make less than the sharp radius turns with these pipe benders. The idea of a wood or plywood form would also be good and I had thought of that. The trouble with the form is that I presume you would need to "over bend" the metal on the form and I don't know how to calculate how much overbending would be needed. Trial and error would be a pain with a radius curve in a big sheet of plywood. I may give one of the cheap tube benders a try first.

 

[bamatoolmaker]

I don't want to hijack the thread but have a related question: What is the best (DIY) way to bend relatively thin wall 1.5 or 2" tubing (like a curtain rod). The radius would be about 16 feet and the pieces would be about 4 ft long. To help you visualize it is literally for bending finished curtain rods to fit a curved window. ??? any thoughts. I have searched around for the type of tubing benders being discussed here but they are all for making much tighter radius bends. I don't know if this type of tool is what you'd use for the wide radius bend or not. Thanks.

Most Fab Shops these days are using CNC tubing benders for accuracy and repeatibilty.I bet you can find one near you that will more than willing to help you.

 

[Farwell]

When I was in my late teens I was a pipe fitter/sheetmetal worker apprentice at the Southern Pacific Railroad repair yard in Sacramento California. One of the Journeyman pipefitters I worked with took a 1-1/4" X8' length of thin wall copper tubing. He soldered a pipe cap on one end and filled the tube with moist black sand. It took quite a while to pack the moist sand to the density that he wanted. I don't remember if he capped the other end or not. Using a brazing rod bent to the shape needed as a pattern, he used a torch to heat the tube and slowly bent the tube into the desired shape. The tube had a couple 180 degree bends in it. I was and am still very impressed.
On another occasion a friend made me a steering wheel out of 1/2 inch water pipe using a torch and a vise to make the circle.
These guys were from the steam engine days when they made everything at the Sacramento yard.
Farwell

 

[HomeBrew2]

... The "pack it with sand" trick helps a lot for greater bend angles and thinner walls. ... Pat

Great! Thanks for the experience. Did you just duct tape the ends of the EMT?

 

[ehchvac]

I have the harbor freight 12 ton bender and have only bent steel pipe like for gas piping or oil tanks and you can make 90 degree bends no problem,... except for pumping the jack handle gets to be a bit much after a dozen bends

 

[Brad_Blazer]

Are those compact bender dies made of aluminum? I might have to make a pivoting tool holder for my lathe and see if I can make a set.

I have a 16 ton pipe bender from Homier. I've had pretty good luck with it. One additional trick I use is to pad the outer rollers with some short pipe halves from some 2" SS pipe. It really cuts down on denting by those rollers.
My local supplier sells sch 40 unfinished pipe that has a very smooth outer surface and bends nice in the hyd. bender. Just make sure the weld is on the inside of the bend. I tried a bend with the weld on the outside and it broke open.
Here are some shots of a tractor rack I made using my hydraulic bender and 3/4" sch 40 unfinished pipe. The boom pole in the pic is the first bend I ever made with that bender. It is 2" boiler pipe.

 

[Brad_Blazer]

An old trampoline frame might yield some nice curtain rods but a 16' radius is bigger than most trampolines. The way to make that bend is to set up 3 wheels sans tires to roll the tube through and adjust the offset until you get the desired radius. The curvature will be so small I doubt there will be an issue with crushing even if the rollers do not fit the tube.