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Can I bend thinwall 6061 aluminum tubing with out damaging it?

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I make high wattage CB antennas. I currently make the coils out of solid 3/8" aluminum #111F rod. I form the coil on a mold I had turned on a machine lathe.

My question is-can I bend 6061 thinwall aluminum tubing(1/2" O.D.) into a coil that would have app. 2 1/2-3" inner diameter on the coil without crimping/damaging the aluminum tubing?

Thanks in advance on any info you can give me.

Gary Meddles
non-profit land management - Marion, Ohio


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There are a couple of things you may want to know about 6061 AL. There are three ways to readily manipulate this material to work it. You can Cold Work, Hot Work, or Anneal and Cold Work. Each of these will provide different results (and you may be limited based on readily available apparati). Some basic facts:

Cold working in the O temper condition is readily performed. The alloy is notably less easy to cold form in the T 4 and T 6 tempers. Hot working may be done in the temperature range of 700 F to 500 F. Annealing should be done at 775 F for 2 to 3 hours followed by controlled cooling at 50 f per hour down to 500 F, then air cool. (Then see cold working)

Often times if you're trying to bend thin walled tubing, you can fill it with sand and TIGHTLY cap the ends before bending (no sand leakage). My recommendation would be to try the easiest (cold working) first, then if acceptable results are not achieved, try either of the other two (as they produce similar results).

I hope that helps.

Tom Beyreis
- Wheeling, Illinois


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Gary,

The info that Tom gave you was highly informative !

I know NOTHING about aluminum ... but your bend ratio of 5:1 sounds OK.

As Tom says, try it cold first of all, preferably around a mandrel ... and use DRY sand and tamp very tight.

The professionals use a liquid that solidifies on becoming cold, ie. the pipe benders do.

freeman newton portrait Freeman Newton
- White Rock, British Columbia, Canada

freeman newton died

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Where can I purchase 1/2" O.D.(thin wall) 1100 aluminum tubing? Any help you can give me would be greatly appreciated.

Gary Meddles
non-profit land management - Marion, Ohio


December 7, 2008

Try McMaster Carr they have everything. I have ordered 1/2" .028 wall aluminum tube from them before.

Larry Hye
- Airway Heights, Washington.


March 25, 2009

Texas Tower has the best selection on aluminum tubing at the most reasonable price. They specialize in material for making antennas.

Dane Rowton
- Idabel Oklahoma


February 11, 2009

Hi,Heinz here; there are plenty of ways to bend tubing, some often involve filling the tube to be bent with non-compressible things. I've seen bismuth and heat used with good success. heard of sand , water, even coil springs being used inside to mitigate wrinkling on the inside of the bend. I've had excellent success with a rotary compression type bender that I got from pro-tools.com.

i had to modify the bender in several areas to bring up the bend quality. first the clamp area was made to hold the tube with more surface area, and the clamp was bead blasted for max grip. the transition from grip area to start-of-bend was made as smooth as possible.both the compression element and the die contact surfaces were polished to a very smooth finish . the die must be absolutely grease free and the compression element must be well lubricated at its two contact points. I bend 1' tubing 180 deg. + around a 3&1/2' die no wrinkles and minor flattening at bend with 1010 low carbon .095 wall thickness. no wrinkles but notably more flattening with same material in .065 wall.i tried .049 wall 1' cro-mo and had even more flattening, no wrinkles, but the stuff wanted to "spring"out of place in the die and would "cripple"or kink unless I allowed zero back creep of the comp. element during the entire bend. I bent.095 wall, 1' 6061 T6 with minor flattening and no wrinkles to 180 deg+.

this is the extent of my experiments to date.i will continue in this, and my colleague,Fritz, and myself will post our findings as we prove them out.i must make clear that we will NEVER post any of these findings as fact unless we have personally proved them out.i chose this method of bending because I did not want to be constrained, or even slowed down by additional steps or variables like heat, grit in tool etc. mandrels being used in the process calls for a more costly bender, but will theoretically produce a higher quality bend in thinner wall tubing. I wanted to have the best quality bend for the least cash outlay. to date it has taken about 11 mo. to get to this level of understanding, and has not been without some problems.Fritz and myself are available for additional info or clarification at site where we are applying this capability to constructing all-metal bicycle sidecars for utility purposes. thanks,HEINZ

heinz heimer
- Napa, California

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