The other day at the LWS/metal vendor's shop I ran into a discussion of bending aluminum pipe. The contractor who was doing the work was completely sure that 6061 T6 pipe won't bend in conventional external shoe types of benders- no matter what.

However, he was having a hard time on his hand rail spec. for his job as the entire pipe spec was limited to 6061 T6 and 6063 was specifically prohibited. So he was looking for 'another' alloy to try to run by his engineer to get the returns bent in a single shot - but believed he couldn't do that with 6061 T6.

I have been bending 6061 for years, always successfully (after learning to smooth the die) using the large radius dies of the Greenlee 555 elec/hydraulic bender. So I chimed in to offer to explain how it can be done - pretty easily too.

He didn't seem to have much faith in my ideas or reports of experience until the owner mentioned he'd been selling me 6061-T6 pipe since the late 1970's and that it was pretty likely I had some idea about what I was describing.

If there are any boat builders, fabricators or others on the Forum who believe the myth that 6061 won't bend in conventional benders- not sure about the super tight radius off road roll cage bender's for tubing with very tight radii?- then I'd like to mention what is needed.

Using an appropriately sized sanding bulb, roller, pad, wheel or 1" belt sander- simply sand the entire die surface to 240-320 - then polish with a cloth wheel on edge with metal polish.

When you go to bend make sure the 3:00 & 9:00 surfaces of the die are smooth with the rest of the interior curve, and lube the pipe and the die until it drips. Can use a variety of lubes- Spray Pam, cooking grease, axle grease type products, engine oils- heavier wts best, or wax, or even the machinist's friend; lard.

The failure of 100% or all my early bends was from the sides of the die galling the pipe side walls, gripping the pipe so it could not flow into the bend and tearing the pipe.

the pipe is plenty malleable, the alloy will form/deform if the radii isn't too tight, and that's all there is to successfully using conventional (rigid steel conduit sized) bending dies on 6061-T6 pipe.

Lots of shops in our location claim that 6061 won't bend- always "breaks". I'd wager this is because the die is galling and about fusing the side wall of the pipe as it 'eggs' in the bend and the pipe is simply torn - not snapped because its too fragile to bend.

Don't know if the contractor got his returns in 6061 or 6063? but last evening a friend and I put a piece of 2", Sched 80, 6061-T6 in a 'triple nickle' and it bent just as smooth as steel would have. I'd polished the 2" die and we lubed the whole show until it dripped and the bend took a few seconds. The pipe is flawless- except for a tiny, thin line along the pipe sides at 3:00 and 9:00 (near the edges of the female die's 'cup') where the pipe had started to seize to the die!! Lucky for us it didn't get wide enough to stop the pipe from moving into the bend.

Hope to add to the knowledge base of anyone bending 6061 aluminum alloy pipe. Because of the copper alloying material in 6063, its not really as corrosion resistant as 6061 and if immersed for long will simply corrode away.

Cheers,
Kevin Morin
Kenai, AK