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Discussion in 'Woodturning Discussion Forum' started by Keith Gwynne, Feb 13, 2018 at 5:14 PM.
How do I bend 1/4inch aluminum rod to make legs on turned vessel like Niel Scobie used to.
Well it depends on how sharp the bend is. Bend it slowly and it shouldn't be a problem. Be sure and do a test piece first. Aluminum will sometimes crack at a bend if it's too sharp. If for some reason it is stress hardened you can anneal it. Heat it red hot and then quench it in water. That is the same procedure you use to harden steel but it anneals aluminum and brass. Again to a test on scrap because there are a lot of different aluminum alloys and they react differently to everything I just said.
They make tubing benders that work well with various types of metal tubing.
You could also turn a radius in wood and secure one end of your metal tubing on the wood mandrel
and press the tubing around the radius. Metal fabricators will use a solid form to heat and bend metal
rods on to for various shapes. YouTube would be a good reference to see various methods used.
Depends on what alloy you want to use. https://www.clintonaluminum.com/which-aluminum-alloy-bends-best/
I didn't think you could quench aluminum without making it brittle again. If you get aluminum red hot, you are very close to melting it. Most references will tell you to coat the aluminum with bar soap. When the soap turns black, that's hot enough. Then let it air cool.
Assuming common aluminum, 6061-T6. Mark it with a felt tip marker. Heat until the marks are gone. Air cool and it'll be annealed. Bend.
This procedure can be repeated if you want to straighten the piece.
Is it solid bar or hollow tubing? In either case, anneal the bend area as mentioned above. If it is tubing and you don't want it to go flat at the mend, there are two things that you can do. The first is to get a tubing bender at your local hardware store. It resembles a screen door spring. In addition to the bender here is a clever hint that I read in the NASA Tech Briefs many years ago: crimp one end of the tubing, then fill it with water, then crimp the other end. Next, stick it in the freezer until the water is frozen. The ice will prevent the tubing from going flat at the bend.
Bending any tubing can be accomplished without kinking by tightly packing the tube with sand before bending. Used to represent a fabricator who did a lot of tubing products.
Edit: Saw the first post- rod, not tubing.
I've used the sand method. It works. I didn't mention it because I assumed he was using solid bar but then you know what they say about Assume.