bending aluminum tubing

[sen2two]

I mentioned this in another thread, but i wanted to be more specific here with it...


I have a JD2 model 3 bender from trick tools and i want to use it to bend 1.75" aluminum tubing with a wall thickness of .080

I have been told by a few people that bending 6061 is tricky. So i would like to know how i could do this with my bender. I know its possible to bend 6061, because plenty of companys sell U-bends made from 6061.

Is there a way to anneal it or a trick to bending it without crakcing or damaging the tubing, or should i be fine when using my bender?

[DougAustinTX]

Use lithium grease in the forming grooves of the dies so the aluminum will slide rather than get stuck and kink. This works on the bender I built from plans on http://www.gottrikes.com/. The lithium makes all the bends smooth and troublefree. Good luck.
Doug

[sen2two]

thanks for the tip...

you reccomend a wall thickness that works nicely?

[Rojodiablo]

Originally Posted by sen2two

thanks for the tip...

you reccomend a wall thickness that works nicely?

With a JDsquared, you won't be able to successfully bend .080 aluminum, unless it is SOFT stuff. In fact, if you go to bend .120 wall 1.75 tube, you will flatten the outside of the tube really badly. A mandrel bender would keep the tube shaped correctly, but it will not adress the stress cracks from work hardening. The best I have been able to do with 6061 was a 2" tube with a .188 wall thickness. Slow, slow bends did it, and it was ok. On all the 1.5" tube that was .120, I had cracks and or flattening that rendered the tube useless for service. I tried sand filling, lube it to death, not much helps with it..080 will wrinkle on the inside, go flat on the outside, or collapse and kink. If you can buy bends, you are better off to do it that way. The JD is a great tool, but it does have limitations. And, the material you are working with is onery when it comes to 6"CLR bends. If you can find a Hossfield bender with an 8" radius, you could do it.

[BrianNye Welding guy]

I have successfully annealed and subsequently bent 6061 T6 and it is quite easy with an O/A torch if you have one. The only hitch being that now it is annealed and needs to be re-heat treated if the part requires full strength, of course if you regularly weld it and don`t post weld heat treat then it is the same thing or pretty close.
The process I learned was to use an acetylene flame to deposit a small amount of soot on the part where it is to be annealed and then proceed with a neutral flame and heat until the soot begins to burn off then stop and let cool. Always worked nicely for my purposes and did not crack and break like T6 always does.

[DesertRider33]

Originally Posted by BrianNye Welding guy

I have successfully annealed and subsequently bent 6061 T6 and it is quite easy with an O/A torch if you have one. The only hitch being that now it is annealed and needs to be re-heat treated if the part requires full strength, of course if you regularly weld it and don`t post weld heat treat then it is the same thing or pretty close.
The process I learned was to use an acetylene flame to deposit a small amount of soot on the part where it is to be annealed and then proceed with a neutral flame and heat until the soot begins to burn off then stop and let cool. Always worked nicely for my purposes and did not crack and break like T6 always does.

Are you the 'Science Guy' from TV ??

[sen2two]

Originally Posted by BrianNye Welding guy

I have successfully annealed and subsequently bent 6061 T6 and it is quite easy with an O/A torch if you have one. The only hitch being that now it is annealed and needs to be re-heat treated if the part requires full strength, of course if you regularly weld it and don`t post weld heat treat then it is the same thing or pretty close.
The process I learned was to use an acetylene flame to deposit a small amount of soot on the part where it is to be annealed and then proceed with a neutral flame and heat until the soot begins to burn off then stop and let cool. Always worked nicely for my purposes and did not crack and break like T6 always does.

this is how i was tought to anneal 6061 plate it school for bending...i just wasnt sure if it would work on pipe/tubing also. just because im curiuos, would you know the temp. your bringing the aluminum up to?

[BrianNye Welding guy]

Yes it works for Tube and Pipe as well....from my search anneal temp is somewhere between 650 and 800 or so depending on the alloy. I found on 6061 the so called torch soot method works just fine.

No, I`m not the science guy from TV.

[sen2two]

one more question about the soot technique, or annealing in general. Do i wait for the aluminum to cool or bend it hot?

also, if im supposed to bend it, or work it cold... does that mean i can anneal it today and bend it 3 days later. by this i mean, does it retain its workability after being annealed, or does it return to its natural state?


this will be for an intake manifold on a car, structual strength is not a concern since it will only be holding up maybe 1lb of material with four of these 1.75" tubing.

[BrianNye Welding guy]

Once is has been annealed it will retain those characteristics until it is heat treated or work hardened depending on the alloy.

[BrianNye Welding guy]

I might add that .080 might mot yield the best results without a mandrel but it may get adequate results for the application. When I did this it was on .125 x 1" 6061 T6. On steel thin wall stuff is difficult so .080" may be a little more of a challenge. Maybe try the lube as Doug suggested. I was using a rotary draw bender as well so I can`t really compare from experience how the two benders may vary in results having not used model 3. Good Luck.

[sen2two]

thanks for the help!

[TSOR]

Annealing as BrianNye Welding guy described, works well. I used the same method to bend 1" x .060" wall 6061T6 using a PT105 bender. I've not had much luck bending past 90deg though.

[sen2two]

How to keep this from happening when using the soot burn off technique...?

(near the end of the video)

You Tube

You Tube

[William McCormick Jr]

It depends on whether or not your tube is "6061 T6" or "60-61 T6 511" The 60-61 T6 511 will crack often with a startling bang if you go to bend it. Even if you anneal the 60-61 T6 511, it will crack or fracture, and show huge distortion in the surface. It will be ruined.

If you have your hand on it when it breaks you will remember it till the day you die. Ha-ha.

They still make 6061 T6, however this tube can anneal in sunlight to 60-61 T0 material. So it is more then tricky it is just plain crazy.

What you want is 50-52, H42 or H52 hardness. Your bender will bend it very nicely. I prefer the H52 because if you over bend just a bit, you can just grab the pipe and open the joint a half degree, and not bend the straight pipe connected to the elbow you just bent.

If you use the H42 and you go to open a joint the straight pipe just bends over the whole length. It can be very hard to work with. On the upside the H42, does maintain a slightly rounder shape right at the elbow and through the elbow.

The H-52 tends to misshapen, slightly near the end of the bend. You can sand this out though.

You have to use a lubricant or a disposable plastic patch, between the shoe and the H-52, to protect the pipe. Or it will draw to much and collapse the outside of the elbow. The H-42 is more forgiving.

All of the below rails were bent with a Hausfeld bender.

You can still see a slight distortion in the elbows done in H-52. I can anyway. A slight hollow on the inside of the elbow. You can sand that out. If you can see it before the paint goes on.







This is how I make the railings. Myself and a fellow from Australia made the program that calculates the length of the pipes, in a Cadd program.





These are all also made with 50-52 H52 material. From Yarde Metal.







It will bend sharply but this is as far as I would go. And only for handrails. Not for high stress moving objects.



Sincerely,


William McCormick

[William McCormick Jr]

The soot works fine, but we use a heating tip or a cutting tip. We keep the blue tips just touching the work. I have never come close to melting a piece, while annealing. But I do have many years of experience. A new guy might melt through a plate though.

I usually do not warp the plate though either.

Sincerely,


William McCormick

[sen2two]

Very nice!

also, for you that have bent .080 wall aluminum tubing (or thinnner/similar) with success, whats the CLR of the bend you were using. i know this can have a huge effect. trick tools offers 5.5 and 6.5 i think for 1.75" OD. i would prefer a tighter bend and go with the 5.5, but im not sure if this is to tight and cause a problem and maybe ripple or break the tubing...

[rode2rouen]

My DiAcro #4 bender uses a follow block to capture the tube firmly in the die. This allows a tighter radius than a Hossfeld or JD2 type bender, along with reduced distortion. The drawback to my machine is being limited to 1 1/4" OD material.

The tube in the pic is 3/4" X .065 6061 T-6, the die is 2" CLR, no annealing was done to the tubing.


Rex


Test pretzel:

[Broccoli1]

Originally Posted by sen2two

How to keep this from happening when using the soot burn off technique...?

(near the end of the video)

http://www.youtube.com/watch?v=QPe6rBPOnx0

Well ya have to consider that there fella had the Alooominum up to temp BEFORE he used the Soot technique.

To be a fair comparison he would need to start with another Cold piece of Aloominum and then see what happens.

[sen2two]

^ahhhh... very true wise one. Just a ploy to sell those temp markers...

[Broccoli1]

Originally Posted by sen2two

^ahhhh... very true wise one. Just a ploy to sell those temp markers...

dunno about that

but he did apply the Soot after he had already heated the AL.

[sen2two]

so just for future knowledge, about what degree does the soot technique get the aluminum to where it anneals it properly.

as in, if someone only had a MAPP gas torch, propane, ect... what temperature would be optimal for annealing since there wouldnt be any soot to burn off?

[sen2two]

did some searching and found this...

http://www.suppliersonline.com/prope...61.asp#General


my guess was 750*, so i was close...

[William McCormick Jr]

Rex

On smaller diameter tubing you can bend a radius like that.

As you go larger in diameter, it gets very bad very quickly. Because of the amount it stretches. The harder tube cannot stretch that much.

I bend solid bars and tube that size myself, and I have no problem at all. But as soon as you hit that 1 1/4" pipe mark you have to go to something else. I use a little Parker Hanifin crank bender.


I know that a 5 inch center line die will not work on a 60-61 T6 and a, one and a quarter inch pipe. I would suspect that a six and a half inch die would not work as well.

As far as heat treating, I was told that it depends on how the pipe was made. If it was either extruded or drawn. One way allows for annealing the other does not. They give the one that cannot be annealed the 511 designation. I have been unable to anneal the 511 aluminum. I believe the extruded stuff marked 511 cannot be annealed.

When I was younger you could anneal all the 60-61 T-6 aluminum there was. But it also turned to 0 aluminum in strong sunlight. So I do not know if the drawn 60-61 T-6 aluminum would be a good choice.



Sincerely,


William McCormick

[William McCormick Jr]

One other thing you might want to consider. As you go larger even with a mandrel bender. You are going to cause, a certain amount of porosity in the metal. As you stretch it that much. You certainly can harden the material substantially as well.

I used to make and repair stainless steel pipes about three and a half inches in diameter. They were bent with a mandrill bender. And you could tell the metal in the bend had been affected by the bend. I used to polish newly bent pipe as well. And again there was a definite degrading of the material that had been bent.

Sincerely,


William McCormick