# Bending Aluminum tubing...??



## Chitownmachine (May 4, 2011)

So I am looking to make some bends in some 3/32" aluminum tubing. Some of the bends are pretty tight. I tried bending it in a bending jig....kink....Then I tried bending it with a lil K&S tubing bender, figuring since they make the tube, this bender has to work.....kink...... I also filled the tubes with a fine sand to give a volume during bending and it still kinked. So my next step is annealing the tubes. So my question is....will this help? Ive annealed copper quite a bit, but no experience with aluminum in that department. Also once bent into shape whats the average heat treat one would use to stiffen those babies back up? Ps...Its K&S tubing so its pretty thin. Thanks for your help!


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## Heatherrose (May 4, 2011)

I heard of a method for bending tubing using Bizmuth, from someone on the www,
who was bragging that they had scored some Bizmuth on Ebay.
He explained that you melt the Bizmuth (melting point around 150 degrees f.),
pour it into the tube, bend it, then heat the tube and pour out the Bizmuth.
Here is another discussion I have come across also discussing a method using frozen soapy water: 

http://www.rcgroups.com/forums/showthread.php?t=1261454

​


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## gbritnell (May 4, 2011)

Here's the link to the build of my V-twin. I bent .375 stainless tube with a bender and cerrobend.
gbritnell
http://www.homemodelenginemachinist.com/index.php?topic=6847.330


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## Ken I (May 4, 2011)

Cerrobend or Woods metal #1 - low temperature alloy - specifically for this kind of thing (and joke teaspoons) melts in boiling water.

Ken


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## d.bick (May 4, 2011)

Not sure how you anneal aluminium but annealing aluminium is something I have to carry out on a fairly regular basis. 
 Using a gentle flame and keeping the torch moving I try to heat a large area using a piece of soft wood stroke the alum whilst heating. The wood will char or leave a black mark when you are at a reasonable annealing temperature. Care must be taken there is not a lot more heat required to melt the metal after this charring of the wood occurs.
              Dave Bick


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## lordedmond (May 4, 2011)

geto method rub some soap on the tube or plate heat till soap turns black and allow to cool




Stuart


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## Holt (May 4, 2011)

If the tube isn't too long, fill with water , put in the freezer, and bend while frozen. I was told it is how they made the frame for the Lotus Elise Thm:

Holt


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## Chitownmachine (May 4, 2011)

Excellent! So many different things to try. Bismuth, Cerrobend, and the ice thing sound pretty cool. Gonna order that stuff up. But first I'll get my freeze on. Thanks for the replies!


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## Maryak (May 4, 2011)

Another option is Resin, melt the Resin, fill the tube, bend cold, melt out the Resin. Resin is tree sap such as used on string instrument bows.

Hope this helps

Best Regards
Bob


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## bearcar1 (May 4, 2011)

To what radius are you wishing to bend and what is the wall thickness of the tubing you are speaking of. Bare copper wire of 24AWG can be TIGHTLY wound around such small tubing and then very carefully bent without risk of kinking. Of course by careful I do not mean that it can be done inside of thirty seconds. One has to 'sneak' up on the bend radius a very small amount at a time, working the bend and keeping the wrapping extremely tight. 

BC1
Jim


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## nev (May 6, 2011)

Maryak  said:
			
		

> Another option is Resin, melt the Resin, fill the tube, bend cold, melt out the Resin. Resin is tree sap such as used on string instrument bows.



Think you mean Rosin
http://www.violinstudent.com/rosin.html


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## Maryak (May 6, 2011)

nev  said:
			
		

> Think you mean Rosin
> http://www.violinstudent.com/rosin.html



Thanks

According to Oxford dictionary rosin is an alternative spelling for resin which is secreted by most plants naturally especially from fir or pine trees, as opposed to synthetic resin which is a solid or liquid organic compound made by poymerization.

I guess whatever bends your bow so it will either rosinate or resonate. :

Best Regards
Bob


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