bending aluminum angle on radius

I need to replace a broken plastic part on an RV. To do this I would like to take some 3/4 x 3/4 angle 1/16 thick that is available in DIY
stores and form it around a radius keeping the cross section more or less uniform. This means that one edge will have to stretch. My question is, what is the smallest radius that is reasonable, with or without heating, to expect using hand tools and a wooden form?
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I expect you are going to have a great deal of difficulty with this plan. Most of the aluminum angle you will find is anodized, and that gives the aluminum a nice hard finish but it doesn't like bending. Also since this is angle, one of the legs is going to be bent the hard way, and it doesn't like to be bent the hard way.
To successfully bend you need dies that will hold everything in position and that will require a bender not just some wooden forms. A way to do this would be to cut off the leg for the distance that you want to wrap around the curve and then make a replacement piece out of flat aluminum and weld the two pieces together, dress the welds down and it will look like angle bent round the curve.
If looks don't matter as much, you can slot one leg bend around your form and use some aluminum filled epoxy to fill the gaps and then paint the thing once you get the cosmetics acceptable.
It might be cheap enough to just buy the plastic part from the dealer, did you try pricing it?
--
Roger Shoaf
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You must have some very fancy DIY stores out your way. I have never seen anodized Al angle in a DIY store.
The key missing piece of information is the radius of the bend.
--
FF


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Our local Ace Hardware carries a (limited) line of bright "chrome" anodized extrusions in addition to the ordinary mill-finish sticks.
LLoyd
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plan.

Most of the AL product is destines to be used as a countertop edge or something hence it is anodized in several finishes.
--
Roger Shoaf
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We get that for carpet edging and such. That's not what I'd call angle aluminum. The DIY stores around here typically have bar, angle, and sometimes round aluminum stocked with the mild steel bar, angle, rod, and threaded rod.
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FF


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I'd also put my vote in for not doing this.... rolling/bending angle is super hard, even with the right tools. Even with appropriate rolling dies etc, typically you end up introducing a twist into the material.
Shaun
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I - and any other metalworking shop that owns a shrinker/stretcher - can probably give you a three-inch radius.
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It shouldnt be a problem, but anodized angle stock will be. Better to start with a piece of sheet, bend the angle, then shrink, then anodize.
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I should have added that the bend is inwards. I am going to try to do it and will report back so you guys that know about metal can all laugh at me! :).The material is not anodized that i can get. Imlike th eidea of fabricating a part by welding but my aluminum welding skills are pathetic. The plastic part was custom molded so is almost impossible to buy. Thanks for nice responses. If anyone needs electric motor help ask me anytime.
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The aluminium angle in the home stores is hardened to T6, almost always 6061 T6, and won't form without annealing. What I would do to make this is make a wooden form and hammerform the shape with a bunch extra, then cut out what I need and clean it up.
I fairly often make round caps for tubes, say 6" in diameter, with a 90 degree flange just about like a hat. You could do the same, but cut out the edge and use it for your project.
Brian
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motor man wrote:

Oh, much easier, assuming that "inwards" means this: with the bent part laying on a table, the vertical leg is on the outside of the curve.
If so, make a series of "V" cuts on the inside leg and bend to close them. When done, use the zinc based aluminum solder ("Alumiweld", or something like that) on the joints. Not as good as welding, but I'm guessing that this application does not need a lot of tensile strength.
Of course this produces a chorded bend, not an actual circle. With sufficient notches you can get close.
Bob
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