Any metallurgists who can advise me on bending aluminium

[Little Dorrit]

I plan to mount an Aries and have some 1.1/2″ x 1/4″ (38.1mm x 6.35mm ) Aluminium Round Tube 6082 in which I need to get a 90-degree bend. Two of these will be attached to the transom vertically with a 90-degree bend and the 30 Kilo Aries wind steering system will be attached (at a distance of 500mm from the transom). I have seen this arrangement on newer and possibly lighter models of the Aries but have been advised that the 90-degree bends will weaken the aluminium, presumably because it will need to be tempered. Can I begin to consider this option or should I discard it and look for alternative mounting options?

 

[sarabande]

Our local agricultural fabricator uses one of these bending tools for ali tube. He uses a propane torch to warm the bendy bit, and is very careful and gently with the hydraulics.

Hydraulic Pipe Bender 16 ton 8 Dies Heavy Duty Tube Bending Tool : Amazon.co.uk: DIY & Tools



Aha, there's even a Youtube video !

Harbor Freight 12 Ton Pipe Bender For Bending Aluminum Schedule 40 Pipe *Actually Worked!!* - YouTube

 

[Little Dorrit]

Our local agricultural fabricator uses one of these bending tools for ali tube. He uses a propane torch to warm the bendy bit, and is very careful and gently with the hydraulics.

Hydraulic Pipe Bender 16 ton 8 Dies Heavy Duty Tube Bending Tool : Amazon.co.uk: DIY & Tools



Aha, there's even a Youtube video !

Harbor Freight 12 Ton Pipe Bender For Bending Aluminum Schedule 40 Pipe *Actually Worked!!* - YouTube

I don't plan to bend it myself but interesting to see how it's done.

 

[vyv_cox]

6082 comes in a variety of tempers and without knowing what condition your tube is in it is impossible to say. The strongest condition T6 is a solution treatment that would be very difficult to DIY. I am not sure if tube in this condition could be bent successfully.

 

[Little Dorrit]

6082 comes in a variety of tempers and without knowing what condition your tube is in it is impossible to say. The strongest condition T6 is a solution treatment that would be very difficult to DIY. I am not sure if tube in this condition could be bent successfully.

I am planning on using T6 but not planning on bending it myself. However, after a bit more research I discovered this link on cold working and forming which is broadly in line with your comments. It does seem to suggest it could crack but the risk of this happening could be reduced. T6 is relatively cheap so I could afford a failure but I am not sure if this means if it bends without any cracks and looks ok that it is ok?

 

[Kilo]

Are you using Ali for the weight saving or because its what you have to hand?
In the grand scheme of things will the weight saving against stainless make much of a difference especially when compared with the strength & relative ease of working of 316?
I don't know the answer but just putting it out there for consideration.
Be interesting to know how the project progresses.

 

[Little Dorrit]

Are you using Ali for the weight saving or because its what you have to hand?
In the grand scheme of things will the weight saving against stainless make much of a difference especially when compared with the strength & relative ease of working of 316?
I don't know the answer but just putting it out there for consideration.
Be interesting to know how the project progresses.

It's a good suggestion and one I considered. However, the Aries is aluminium and the tube need to slot into aluminium cross tube casting. I don't think it's possible to isolate the aluminium casting from a stainless tube easily. There are few options but most require the tube to be bent.

 

[Kilo]

Yup the mixed metals would need sorting out.
Have you seen these:
Kee Lite | Buy aluminium tube clamps online - Simplified Building
I've only used the malleable iron version & not on a boat but they are v effective & 5 Yrs on from fitting in a fairly critical heavy use fabrication, the grub screws remain tight. Might be worth a look.

 

[Greenheart]

I can't visualise the Aries problem you're trying to solve, but your description did remind me of a current project of mine...

...fitting an outboard bracket to the back of a sailing dinghy which was never built to carry one.

I certainly came up against the necessity to isolate different metals, but I'm confident that I can solve it, because the different diameters of the tubing will allow the inner pipes to be encapsulated in inner-tube or something similar.

The main thing I needed was 90-degree 'elbows', so I could make a ply transom between the down-parts, and insert narrower yard-long aluminium horizontals (for lightness) as levers to counter the weight (and thrust) of the engine hanging off the back.

The set-up in the photo below was only to see how neatly the elbows hug the transom. I had been afraid their radius might cause problems. Obviously I'll need to address various issues irrelevant to this thread...

...but I'm really pleased with the automotive exhaust elbows. They are 1.5-inch (38mm) diameter and 1.5mm thickness, stainless 304. Other diameters are available.

I don't know whether car exhaust sections are available in 316 stainless, but I do know how long I looked online for curved-section metal piping, before finding these at about £8 each, from Profusion Exhausts. Tube / Bends - Page 1 - Profusion Exhausts LTD

I looked seriously at buying straight tubes and bending them with costly tools, or paying a metalworker to do it for me, but was glad to find what I needed on sale already bent. They weren't so easy to find - there are surprisingly few sellers.

I didn't find 90-degree elbows in aluminium, so I have to isolate the aluminium pipes from the steel bends. No big deal.

 

[TNLI]

I plan to mount an Aries and have some 1.1/2″ x 1/4″ (38.1mm x 6.35mm ) Aluminium Round Tube 6082 in which I need to get a 90-degree bend. Two of these will be attached to the transom vertically with a 90-degree bend and the 30 Kilo Aries wind steering system will be attached (at a distance of 500mm from the transom). I have seen this arrangement on newer and possibly lighter models of the Aries but have been advised that the 90-degree bends will weaken the aluminium, presumably because it will need to be tempered. Can I begin to consider this option or should I discard it and look for alternative mounting options?

I would not use alloy tubing to mount anything that can move unless it is thick walled scaffolding tubes that do not need bending. Problem is metal fatigue. Stainless steel or hot dipped galvanised mild steel is the only way to go.

 

[TNLI]

It's a good suggestion and one I considered. However, the Aries is aluminium and the tube need to slot into aluminium cross tube casting. I don't think it's possible to isolate the aluminium casting from a stainless tube easily. There are few options but most require the tube to be bent.

Duralac or if you need some serious adhesion, SABATACK 750 XL which is in white, black or mahogany.

 

[ean_p]

I plan to mount an Aries and have some 1.1/2″ x 1/4″ (38.1mm x 6.35mm ) Aluminium Round Tube 6082 in which I need to get a 90-degree bend. Two of these will be attached to the transom vertically with a 90-degree bend and the 30 Kilo Aries wind steering system will be attached (at a distance of 500mm from the transom). I have seen this arrangement on newer and possibly lighter models of the Aries but have been advised that the 90-degree bends will weaken the aluminium, presumably because it will need to be tempered. Can I begin to consider this option or should I discard it and look for alternative mounting options?

If concerned then have a web fitted in the crook of the bend. If done with some style and maybe a lightening hole or three it may enhance the look of the brackets.

 

[vyv_cox]

Stainless elbows in the size you want are definitely available. The exhaust on my kit car was fabricated using a variety of different elbows. I think it is 40 mm OD but various sizes are available.