Bending 1.25" OD water tubes 90º on a JD2, which material to buy?

[Richard/SIA]

Beating my head against this obstacle, WHICH alloy to use in making new 1.25" OD water transfer tubes?
No idea which stainless the tubes vendors sell are made from.
I expect they have a mandrel bender, I do not.
Just buying transfer tubes and having them shipped appears to be about $900.00 now.
I should be able to form my own for about half of that.
I have a JD2 with hydraulic conversion and 3.5R dies.
Made a trial run with readily available 304 stainless, result was not good, maybe in a fully annealed state?
Aluminum 6061-T6 is also useless, maybe T4, or O?
Of course the useless alloys are all that is readily available locally or on-line.

Someone should have the alternatives in stock.
I expect to have to make a long drive to pick it up once I find a source.
I am near Reno NV, a drive to LA, San Diego, Sacramento, SLC, are all possible.
I will need a minimum of two 10' lengths.

 

[memphisjed]

Tube wall thickness? Thicker is better
What is water transfer pipe?

Not sure what jd2 bender is- thought it was rotary draw, if so rot gut 1 inch sch 40 bends all day every day. Can you dial it in on steel first? Ss and steel follow same math bending.
Bending aluminum sucks on a good day. Aluminum generally is miserable to work with, bending pipe out of it- worse.

 

[rimcanyon]

Maybe weld instead of bend? You can purchase pre-cast stainless elbows for welding.

 

[Rob F.]

Tube wall thickness? Thicker is better
What is water transfer pipe?

Not sure what jd2 bender is- thought it was rotary draw, if so rot gut 1 inch sch 40 bends all day every day. Can you dial it in on steel first? Ss and steel follow same math bending.
Bending aluminum sucks on a good day. Aluminum generally is miserable to work with, bending pipe out of it- worse.

The JD2 bender is a hossfeld design but optimized for bending tube.

 

[Rob F.]

As memphisjed said the wall is probably to thin.
You can try to pack it with sand so it will not have room to collapse in on itself but this is usually done for hot bending of steel tubes. Another way to bend thin wall tube is to fill with water and freeze it so it is full of solid ice. This may not always be possible.
Easiest is to just buy sanitary tube fittings and weld them in, I like the ones with a tangent on them (short straight section)
Here is a link to 32mm ones on ebay, no tangents though.
You will find that 1 1/4 tube fittings are not common for stainless, most skip over from 1" to 1 1/2" so your best bet is probably looking for it in 32mm

 

[Lee J]

Since you did not specified specify {late edits} what kind of pressures are involved, I'll make a wild assumption that they are not too high. If they're fairly low, you might be able re-purpose 304 or 321 SS mandrel bends used for exhaust tubing (presuming you can do (or sub-out) welding to join pieces. Some sources to look @ include --

Exhaust Components - SPD Home Page B

SPD offers a complete line of exhaust components for Exhaust Fabricators ranging from Mandrel Bent Tubing, Mandrel Bends, CNC Header Flanges, Merge Collectors, Collector Flanges, Stainless Bellows, V-Band Clamps and Sealing Flanges, and Formed Collectors & Accessories.

www.spdexhaust.com

https://www.mandrelbends.com/mandrel-bends/304-stainless-steel-16-gauge.html (multiple sub-pages here with various tube ODs, wall dim., bend angles - they also have more SS alloys, but sizes may be limited)

Some of the other racing supply outfits might also have choices, but not too much demand for 1.25 OD racing exhausts!

Lee

 

[BT Fabrication]

Beating my head against this obstacle, WHICH alloy to use in making new 1.25" OD water transfer tubes?
No idea which stainless the tubes vendors sell are made from.
I expect they have a mandrel bender, I do not.
Just buying transfer tubes and having them shipped appears to be about $900.00 now.
I should be able to form my own for about half of that.
I have a JD2 with hydraulic conversion and 3.5R dies.
Made a trial run with readily available 304 stainless, result was not good, maybe in a fully annealed state?
Aluminum 6061-T6 is also useless, maybe T4, or O?
Of course the useless alloys are all that is readily available locally or on-line.

Someone should have the alternatives in stock.
I expect to have to make a long drive to pick it up once I find a source.
I am near Reno NV, a drive to LA, San Diego, Sacramento, SLC, are all possible.
I will need a minimum of two 10' lengths.

304 will only bend slightly before breaking. 400 series is common to use to bend exhaust pipe, i think its 427 and 430 something

 

[Graham Gott]

JD2 recommends a min wall thickness of 0.083" for your 3.5" radius die set. Stepping up to 4.5" radius drops their min wall thickness recommendation to 0.058". I'm assuming that is for mild steel tube, but would make bending stainless or aluminum easier as well. McMaster sells two different types of 6061-T6 tube. Part number 89965K741 is listed as bendable and flare-able, I'm assuming it's drawn rather than extruded. Part number 9056K76 is listed as extruded tube with no mention as to it being bendable.

 

[lastrada]

How about the old school method of packing it with fine sand and heating it with a torch.

 

[memphisjed]

Are your dies for 1 inch pipe or 1 1/4 tube? 1 inch pipe likely priced less. 1.3 od.

 

[boslab]

Cerro bend and a hydraulic bender, melt it out after, or the packed sand as mentioned, needs capping for that
Mark

 

[Richard/SIA]

I have been looking for .085 wall.
I have the 1.25"x3.5R dies.
I thought of Cerrobend but that would also be very expensive for a one time use.
I've looked at buying bends and welding, that may be my last resort as I really prefer single piece tubes.
Water transfer tubes run from the radiator up front to the engine in the rear of a classic Lotus.
It's a long way so I need smooth bends, the water pump did not originally have to push water so far.

 

[boslab]

Oh I see, cerro certainly isn’t cheap, but it’s completely reusable, you can get away with modelling low melt from craft stores, practically the same stuff I’d guess, bismuth antimony type stuff, but oil the tube first, and polish with a bit of Emery on a split dowel in a drill.
If rough it can stick on a bit, mandrel tube is best, ERW has a rough weld, not good for flow.
Ali Extrusion would do, the wall would be thick for unsupported bending .
What was the original made of?
I watched a video recently of thin brass tube for a trumpet being bent, the water bath and freeze method was being used, they were pulling 180 degree bends fairly easy, no mandrel cool literally.
Never tried that way.
Mark

 

[jackalope]

I’ve bent a lot of SS tube on my JD2 model 3 over the years. I only bent 45• bends using a 1” tube die and tight CLR. The parts were used in a crucible to melt silicon into massive ingots for computer wafer production.
It was 304 iirc. Slightly heavy wall (~.090”) but it worked fine.

 

[Richard/SIA]

Car is a Lotus Europa.
1.25" seems to be an "Odd" size in the sourcing world.
Originals were thin plain steel, some folk have used exhaust pipe.
I would something a bit more durable.

 

[Fish On]

Bending aluminum sucks on a good day. Aluminum generally is miserable to work with, bending pipe out of it- worse.

Nothing wrong with bending aluminum pipe. Those of us that deal with marine parts do it all the time.

6063 is usually considered the correct alloy for bending, not 6061. If stuck with 6061, simply anneal the bend area.

1 1/4" tube with a 1/8" wall should bend like a dream on that bender.

 

[Richard/SIA]

I gave up and paid the piper. (No pun.)
Ordering from the UK saved me around $400 over buying from a US source.
ALL of that savings is shipping, I honestly do not know how industry survives here with shipping cost being so insane.
From the UK my shipping and item cost are nearly the same.
I should have been able to just buy tube and bend my own, but shipping cost even for strait tube is ridiculous unless you order a full load.