Aluminum forming question

[cactusconcha]

Hi Fellas,

I am new to this forum. My sister who has a sailboat turned me onto you all. So here is my question...I need to form 1/4 aluminum sheet into a quarter circle...think 4 inch pipe kind of curve. The length of the piece would be about 10". What is the best way to achieve this...and what type of welding would you recommend (TIG)? when I get it formed.
Thanks ahead,
Cita

[Rick Willoughby]

The best way is to use a 3 roller pinch press like this:
http://www.carellcorp.com/SIHR.htm
The aluminium will cold form nicely unless it has an extremely high temper.

If you do not have one in your shop then you might be able to get a local tech college or metal fabricator to help out.

The force required to bend even a 10" length of 1/4" is significant. You could make a strong-back for a hydraulic jack loading a piece of heavy wall steel pipe and pinching between two similar pieces of pipe fixed to the base of the strong back. Just keep nipping and moving the piece back and forth with slow increase in the amount of bend until you have what you want.

I doubt that you would have a vice that could exert the required force.

Another option is to just get a 10" offcut of 4" aluminium pipe from the local metal merchant and cut a quarter out of it.

You can heat the aluminium to reduce the force required but it will need a large heat source as the aluminium conducts heat really well. This is NOT recommended though as you will likely destroy the metal temper and can dramatically change its properties.

Rick W

[cactusconcha]

Thank you Rick,
Would you explain strong back to me please? I have sent you an e-mail with the exact situation...sure do appreciate the information.
Thanks,
Cita

[Rick Willoughby]

The strongback I had in mind would have two side plates, two pinch tubes at the base and a locating collar for a jack to react against in the top plate. It is simply a means of locking in the force produced by the jack. THe heght depends on the height of the jack and it needs to wide enough to accept your 10" long work piece.

Rick W

[whoosh]

um you could just split a tube? or as rick says make a press a simple copy of press brake, lots work for one piece and a small diametre so you press from the outer and work to middle, pardon me I,m just passin time:!:

[cactusconcha]

Thank you all for your insight. I cut my piece of stock last night and am going to try shaping today. Your input has saved me a h--of a lot of money, I am sure. Once I get the piece formed there is a fella here that is a certified alum. welder...way better option than my turkey turds:)

Thanks again you all,
Cita