# need advice on forming alum pieces



## joebiplane (Oct 7, 2011)

I want to make about 50 sets of formed aluminium pieces 
the first is basically a right angle with a small flat at the 90 degree corner  the second looks sort of like the copper bracket that is used to secure a water pipe to a wall or ceiling joist.
the clamps or pieces will be used to form a brake on 1/4 in alum tubes and allow to connect rectangular alum tubes perpendicular to the 1/4 in tubes running longitudinally 

project is a 1/4 scale fuselage of a home built aircraft (Murphy renegade)  and I want to mimic  the full scale construction methods and the extruded pieces Murphy used on the full scale  Actual miniature extrusions are  WAYYYYYYYY cost prohibitive
So much for history I am wondering what the best way to create a form  for the bending and what kind of press might be required... This is new territory for me and I am looking for a bit of advice  I have a horror freight 12 ton press   but I'm looking for ideas for the forms I will need to create  and Press  and  what material  to use for the form and I'm assuming  T-6 alum will be used for the parts i will be creating  at .030 or .050 thickness. I will need to experiment on that matter
Any ideas ???????????
Thanks....As always....  Joe


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## Tony Wells (Oct 7, 2011)

Here is a guide on aluminum grades:

http://www.universal-stainless.com/agrades.html

There are several that lend themselves to forming, some require heat treatment after forming to achieve their ultimate strength.

Your 12 T press will be plenty. Forming dies like you want are simple to make. Just remember to smear some lube on the strips. You will need to buy strips of the proper width, or if you have a shear, shear them up prior to forming.


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## bvd1940 (Oct 20, 2011)

joebiplane said:


> I want to make about 50 sets of formed aluminum pieces
> the first is basically a right angle with a small flat at the 90 degree corner  the second looks sort of like the copper bracket that is used to secure a water pipe to a wall or ceiling joist.
> the clamps or pieces will be used to form a brake on 1/4 in alum tubes and allow to connect rectangular alum tubes perpendicular to the 1/4 in tubes running longitudinally
> 
> ...



Dont try to reinvent the wheel just go to a site that sell dies and look at the specs, or Google specs for press brake dies, as for material use a machinable tool steel you can harden.
I know it a vague outline but kiss statement holds true for me. 
Good luck.
Bill in SE Idaho
One other thing aluminum has a soft side & hard side so if you bend inside bend on hard side you will have better luck.


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## awm_1 (Nov 26, 2011)

joebiplane said:


> I want to make about 50 sets of formed aluminium pieces
> the first is basically a right angle with a small flat at the 90 degree corner  the second looks sort of like the copper bracket that is used to secure a water pipe to a wall or ceiling joist.
> the clamps or pieces will be used to form a brake on 1/4 in alum tubes and allow to connect rectangular alum tubes perpendicular to the 1/4 in tubes running longitudinally
> 
> ...



Unless you have to use T6 for some other reason 2024T3 could  probably be formed without cracking. I used to form parts with forming blocks made as a positive of the form I wanted to duplicate made of phenolic or hard wood and a press. The block would be laid down first with the aluminum, sometimes taped to the block to prevent movement, then a heavy rubber (ours 2" thick) over that then pressed. The rubber would pressed closely against the forming block, forcing the aluminum to follow the form, worked well. Sometimes had to tweek the block or add lube if something didn't fill in or the rubber tore the aluminum. Do you have a drawing of what you want to form maybe I could look it over and guesstimate a form.

Wayne


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## Hawkeye (Nov 26, 2011)

Joe, the 90* pieces can be hammered over in a vise. I'd suggest rounding over a piece of angle iron (as vise jaws) to use on the inside of the bend, just so the bend doesn't end up too tight. Aluminum is sensitive to stress cracking if it gets abused in bending. The other pieces (in the absence of pictures) sound like there are no tight bends, so wrapping around a suitable pipe or rod should work.

Very important not to impose scratches or other stress-causing features. A nick is where a piece will break, sometimes after years of vibration, such as caused by a small gas engine.

What grade of aluminum will you be using? I don't know the numbers, but I've had fun bending landing gear out of aircraft-grade stock. Just when you get close to your final angle, it snaps off. You have to heat that stuff, then cool it. Then you have 25 minutes to do all your bending. After that, it hardens up again. Pretty cool stuff.

How does a scale frame compare to full scale for weight and strength? I've never found any information on that part of design.


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## DMS (Nov 27, 2011)

I am having a little trouble picturing your part, but if all you need is 90 degree corners, something like a press brake might work. If you are using aluminum, and it is not too thick, you could probably "fake it" with an arbor press or a bench vice and a homemade die. I am thinking a 90 degree V point on one half, and a 90 degree V channel on the other. Maybe some alignment pins to make sure it's all stays aligned. 

Depending on your thickness, could you maybe start with aluminum angle, and cut small pieces, modifying as needed?

I think Pete is right about the alloys. As I recall, you are going to want 1000 or 3000 series. If you go with sheet it should be one of those, and readily formable.


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