Wednesday, March 12, 2014

bending-aluminium-rectangular-tubing-need-help



Hi Everyone
I am busy making an aluminium table (which is very unique in design) and that requires some bending. The tube size is 100mm x 50mm with a 3mm wall thickness. The two tubes are 3 meters in length each and requires two bends in the same direction each. (photo attached)
I need help with this one, none of the steel companies wants to help because they dont have the bending equipment because of the size of this tube and are scared of breaking it.
My last resort is bending it myself. Can anyone please advise on what would be the best way to get this done if possible. I dont want to give up on this project.

I can't imagine any way that you will be able to bend square tubing like that. Normal way would just be to cut 2 pieces at a 45 degree angle and then weld them at a 90. Won't give you the smooth curve of course.
Otherwise you would have to use 4 pieces of flat stock cut and bent to size, then welded in that shape.

Bending tubing of any type requires the proper tooling. The tubing must be supported as much as possible to prevent it from collapsing or wrinkling during bending. It's not the sort of thing you can do with a simple tubing bender or press break.
What is the alloy? Has it been heat treated or anodized?
Honestly, it would be easier to bend solid bar material. The material may be a bit more expensive but it is much more easily worked since you don't have to worry about crushing the hollow tubing. And, if you can get material that has not been heat treated it bends very easily.

Thank you for the responses. The cutting out, bending and welding sounds like a good idea. No one have suggested that one to me yet. I have heard of people using sand, i might try that but with this size it doesn't sound like it will work, dont know?
Steel is too heavy as this will be a mobile table (console to be exact).
Again, thank you for the in put, much appreciated.

I'm sure that was done on some type of real expensive machinery and then heat treated after. If you have access to a tig welder with AC you could use an existing leg as a pattern and cut two identical side plates and do a simple bend creating two inner and outer pieces to weld together. I have done old automotive frames something like that but using steel. Good Luck

If the tube is hollow, fill it with sand and cap the ends before you bend it. It will help prevent it from kinking.

Have you figured out anything yet.
When you see such a smooth radius it could have been cast.
When you bend anything fairly tightly you always wind up with too much material on the inside that has to go somewhere.

Do not believe that you can bend that - you can. However achieving a 90 degree radius will on what appears to be 3/8s will require a 85 degree break press and it will look no where near as nice as the image above. That being said there are several places where you can purchase extruded profiles and accessories such and angles that can be joined to the profiles. Try googling - aluminum profiles and accessories.

Look up a product called Cerrobend. It is a metallic alloy with a very low melting point 200° F. You just melt the alloy, fill the tubing, let it cool, make the bend, then heat the finished product to remove the alloy. It is reusable. Good luck. If you go this route, we would really like to see the result.

You could try filling the tube with water then freezing it.
The frozen water inside will keep the tubing from collapsing during the bending process.
This a variation on hydro-forming bending process. Your results may vary.
I saw a you tube video on doing this with copper pipe..






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