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best way to bend solid aluminum rod and sheet ???

Discussion in 'Home Brew' started by BOOTY MONSTER, May 6, 2010.

  1. ill be getting some solid aluminum to use on a antenna . i went online to double check that i had a good idea on bending to the shapes i want . im finding conflicting information on doing it so i figured id ask you folks how to do it at home . ill be using solid aluminum rods from 1/4 inch to possibly 3/8 inch diameter , itll be 6061-T6 or 6061-T651 aluminum .



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    i was thinking about just making a simple jig with 2 hefty bolts using one as a brace and the other as a post to bend around . im kinda concerned that it may crack or sheer off at the bend going by some of what ive read . ive read that using a torch to heat and slightly soften it before turning is the way to go about it , but i thought id check with yall to see if thatll work or if theres a better way to do it at home and keep it cheap .


    thanks .
     
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  2. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    Using a torch on aluminum can be tricky. It tends to go from solid to liquid pretty fast. I would use something like a pulley and place the rod in the pulley groove. Anchor one end of the rod near the pulley and GENTLY apply force to GENTLY bend the rod.That's what has worked for me.

    As for sheet, you're on your own there.Without a metal break it gets tricky to bend it without cracking the bend. The trick is to make a gentle arc and not a real sharp bend. The thinner the sheet the easier it is to bend of course. I clamp the metal and a piece of wood together in a vise and use a rubber mallet or dead-blow hammer to bend the aluminum over the edge of the wood. I make the bends first and then trim to size after.
     
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  3. swanny

    swanny Member

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    booty, the process i think you are referring to is called annealing. Take an oxy acetylene torch, turn on acetylene only, it will be black and nasty little carbon wisps flying everywhere. run the torch over the metal and coat it with that soot getting somewhat close to transfer some heat as well. if youre not running oxygen in the mix you won't have to worry about it getting hot enough to melt. When you are done, you can wipe it off with a cloth. If it was me, i would try and make a jig that has the radius you want, like a piece of pipe, so that the stress is distributed more equally than a single point like two bolts would do.
     
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  4. swanny

    swanny Member

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    and as for plate, i would use that same annealing process say two or three inches either side of where the bend will be. Try and clamp the sheet down with plywood on top of it, and maybe two pieces sandwiched and clamped on the side you're going to be moving. once the metal is annealed it "gives" alot more without breaking. You should be able to get a nice bend this way. Don't forget to coat both sides tho.
     
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    Last edited: May 7, 2010
  5. DXman

    DXman Well-Known Member

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    CORRECT.......
     
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  6. swanny

    swanny Member

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    You guys are way smarter than me when it comes to radios, but I have been a welder fabricator for fifteen years :)
     
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  7. mackmobile43

    mackmobile43 Jock Supporter

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    Yep I learned about the annealing process watching Jesse James making fuel tanks for custom bikes.

    Now teach them how to temper that aluminum.
     
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  8. packrat

    packrat Active Member

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    Ok, now you have annealed the aluminum, making it butter soft....good,... so how are you going to put the strength back into it after the bending?
     
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  9. swanny

    swanny Member

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    KEY to METALS Articles: Heat Treatable Aluminum Alloys

    depending on the size and configuration, I don't know that i would mess with trying to harden the sheet after it has been bent. Depends on what you're gonna use it for. As the article says, you can heat treat and quench some aluminum. Annealing will make it easier to work with but if you're talking about solid stock round aluminum, it's not gonna be just butter. Bending it round for something like a gamma match, it will hold it's shape just fine after forming. Also, the more temper you put into a piece of metal, the more brittle it becomes.
     
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  10. packrat

    packrat Active Member

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    I personally never worry about annealing any aluminum I work with. Anything that you will use for building an antenna will be easy enough to form as is. You don't think the antenna manufacturers anneal, do you?
     
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  11. ill be bending either 1/4 inch 5/16 or maybe even 3/8 inch diameter solid aluminum rod . heres the specs for it .

    6061-T6 and 6061-T651
    ALUMINUM ROUND
    Federal Spec QQ-A-225/8 Cold Finished
    Federal Spec QQ-A-200/8 Extruded
    12 Ft. Length

    i havnt seen any cb antenna builders use solid aluminum rod of that thickness and i have no idea how antenna manufacturers build their products . usually aluminum tubing and cast hubs and SS brackets are used .

    ill have some 3 foot scrap peices to pratice with using the suggestions here so far .

    thanks folks ;)
     
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  12. swanny

    swanny Member

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    You might have to use more heat than just annealing if you plan on making sharp bends with the thicker solid rods bootymonster.
     
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    Last edited: May 7, 2010
  13. Shockwave

    Shockwave Sr. Member

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    I've had great luck just using a propane torch. I've heard the carbon of acetylene only works better but propane works fine. It should be fairly hard to melt the material with just propane if it's at least 1/4 inch. You don't have to bring the temperature too close to the melting point to soften it either.
     
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  14. packrat

    packrat Active Member

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    Try it cold first. Sizes that small shouldn't be a problem. I used to build fire and rescue vehicles from scratch, most were aluminum bodies, and i don't think I ever needed heat except to weld em together. Aluminum is pretty soft, and unless you are bending complex shapes or heavy stock, it should bend fine. The idea of using a pulley, or other round form for shaping round or square stock is a good one, too. A break or brake press will make flat work easy, but clamping angle to a work bench works, too. I wouldn't beat on it though, as it leaves unsightly damage and causes stress points.
     
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  15. mackmobile43

    mackmobile43 Jock Supporter

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    Tubing 3/8'' and lower is easy enough to just fill with sand and bend.
     
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