Bending Aluminum Tubing

[Anonymous]

I am trying to replace a Waterwitch exhaust tube. I have the correct diameter thin wall aluminum. How do I get a nice bend at the exit that I can then flatten as per the original? I took it to muffler shop and they got wrinkles. It has been suggested an electrician could do it with a conduit bender but I have never seen 1 3/8" conduit.

Other suggestions? Is this one of those things where I will have to fill with sand, plug ends, then bend… somehow, etc.

Bob Huff

[joecb]

Bob you will have trouble bending tube that has a thin wall absent the availability of properly sized forming dies. You might try using tubing that has a thicker wall, that will be less likely to kink. You might check out an industrial hydraulics shop, one that makes up hydraulic hose & tube assemblies they may have the correct size dies… but still the thin wall may be a problem.

Joe B

[gjonz]

Okay…stay with me here…

One option is to fill it with pitch…a black tar substance…and let it harden after pouring it in and filling the tubing. Then bend it. But where you find that stuff today…I dunno.

Next is close the ends after filling with water…and freeze it. Then bend it. This I how trumpets and trombones are made.

Or…again work with me…take it to a music instrument repairman who works on trumpets…trombones…and…TUBAS. He’ll likely have mandrels that he could not only bend it…But then straighten the wrinkes as needed.

Am I nuts?

Nope. My trombone tech used to get dents out of my exhaust for me often. Lol

Greg

[Anonymous]

or fill with wet sand.

[wiscoboater]

My father worked at a machine shop where he would make hand formed copper heat treating coils for American Motors and GM. He would fill the copper tubes with sand before bending, packing the sand tightly in the tubes. I do not know if it will work with aluminum tubes but worked great with the copper.

[joecb]

All good advice, that is filling the tubes. I didn’t mention it because the metal is expensive but there is Cero-bend, a low melt (160*F) bismuth alloy that is intended for just such jobs. The problem that I see is the thin wall and the relatively large diameter, not sure if even the cero-bend would work with out cracking the tube. You could try the pitch (would be much cheaper). Hard pitch is what the commercial roofers use on built up roofs. The stuff comes in big paper wrapped cylindrical blocks, gets broken up with an ax and melted in a fired pitch tank. Go find a roofing contractor that does hot pitch built up roofs… he should give you a small chunk.
Joe B
PS, freezing water will burst the tube

[Monte NZ]

I have melted lead in thin walled brass tube successfully when doing model work.
I don’t know how you would get on with aluminium …….might be worth trying on and old bit and see what happens.
When I made haws pipes for a model 1466 Landing Craft years back I put bits of lead into the pipe, sealed it a one end,heated the lead until melted, let it cool ,made the bend and then held the pipe up and reheated it until all the lead ran out.

It worked well…….the most important part was to only heat the pipe enough for the lead to run out…….if you got it to hot, the lead would tend to fuse to the brass.

Cheers
MonteNZ
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[crosbyman]

google the subject lots of utubes to watch

Joining AOMCI has priviledges 🙂

[jeff-register]

In the past being an Electrical Contractor we had to place raceways for communications. We bent 3/4" aluminum conduit in a EMT tubing bender. Only issue was the phone company only allowed 270 degrees at most between junction boxes. I don’t remember anything different about bending aluminum. Maybe it was a thicker wall than EMT but we had no issues. Then again the new Ford trucks lost 700 pounds going to aluminum but damage was replacement not bending straight again. That had to be over 20 years ago for running aluminum tubing. Many things have changed from back 20 years except the price of gasoline ;)!!

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