bending sides of square aluminum tube

[willisZ]

I want to bend out the sides of a square aluminum tube - but don't know if the alloy the tube is made of will bend or crack. It's a 2" tube with 1/8" walls.

will bending it be okay, or will it weaken the bent area and possibly crack and fail later?

any thoughts?

 

[jasonh]

The answer is..... it depends.
My thought is try it and see, it will definitely weaken in the bent area, but at 1/8" thick it'll probably still be ok.
Don't do it if anybodies life depends on it.

Jason H.

 

[starbolin]

Thick wall square tube is most likely 6061. 6061 is cold workable. We bend it to about 5x radius ( I forget ) on width all the time. Also available in 6063 which is easier to bend and takes a tighter radius.

 

[sunworksco]

You may want to heat treat it after forming.

 

[willisZ]

thanks for the responses! I guess I'll try bending it.

what do you mean by heat treating? hit the area with a MAP torch?

 

[sunworksco]

[/B]Heat Treatment

Solution heat treat at 990 F for adequate time to allow for thorough heating and then water quench. Precipitation hardening is done at 320 F for 18 hours and air cool, followed by 350 F for 8 hours and air cooling.

 

[willisZ]

I don't think I'll be able to heat treat it in my garage... Guess I'll just hope for the best!

 

[sunworksco]

You can heat it in your kitchen oven.

 

[dcflysrc]

What is the part for? That might also help with the question that you posted.
you will obviously weaken the strength and rigidity of the material. I would think that cold forming will induce stresses as well in the areas that are cold formed. anyway good luck and hopefully it works out for you. DON

 

[chipenter]

You have to cut the sides out try bending the offcuts , will tell you iff it needs anealing .

 

[willisZ]

It's for a camera jib arm - or mini-crane. the arm I'm using is 1.625" - and the inside of the square tube (which is the upright that the arm pivots on) is just a little smaller than that. I only need to add about 3/16 more width to fit the arm in.

I'm going to try heating with a torch, and then hammering through a tapering wooden form to force out the sides.

the total weight the square tubing will be holding up is only about 40 pounds.

I'll let you know what happens!

 

[Tin Falcon]

personaly I would not worry about the heating. The wooden drift is probably the way to go. I assume you are making one or two. I recomend making the drift consideablt like 3/32 oversized. or even 1/8. two reasons 1 you will get spring back. . 2 it will be much easier to cruch it back a little if needed than making a second drift. I also recomend hard wood like a maple.
Tin

 

[willisZ]

thanks - I didn't know it was called a "drift". always something new to learn!

 

[Tin Falcon]

Definition and explanation like I said earlier the liitle bit you need to enlarge the hole i do not think you need to heat the aluminum.
Tin
Drift: A tool used in blacksmithing to make holes the correct size and shape. A hole is punched or cut in the material and a drift is forced through that hole to enlarge it to a particular size and/or to change its shape (make a round hole square, for example). The drift is tapered at both ends so that it starts easily in the hole and when the final size/shape is reached will then fall out of the hole after a few more blows of the hammer without getting stuck. Drifting is done while the metal is hot so that the metal will stretch to fit the intended shape.

 

[Diversion900]

You may also need an external size limit guide to save the sides from ballooning out due to the fact that you will be expanding the width at two points per side.

I have tried similar things in the past, and found that 1/8 plate takes a fair bit of persuasion to get into the sort of shape you are after.

Don't know if my explanation makes sense, but worth a thought all the same.

Good Luck. Let us know how you get on

Cheers, Neil