Replacement coolant pipe wall thickness.

lidox19

lidox19

True Classic
Hi All,
What wall thickness pipe are you using for replacement stainless steel coolant pipes?
I have found an exhaust supplier that sells 35mm diameter t304 stainless steel in either 1.5 or 1.2mm wall thickness up to 6m long.
I'm planning to have a go at bending the pipes myself.
Thanks
Andy
 
Stainless steel is hard to bend, unlike mild steel which if you over bend a little you can push the bend back out a few degrees with no issues, not with stainless steel. It work hardens, so the more you bend / fold a piece the harder the material gets. So measure three times and bend "short" a couple of degrees and double check.

It probably wont actually be metric 35mm OD tube either, most likely an imperial equivalent, 1 3/8" perhaps, which is very close.

standard the steel pipes are approx 1.25mm thick. the pipes actually neck down after it passes thru the tunnel too, the ID of the hoses is 32/33mm, and a very tight fit over 1 3/8 tube.

SteveC
 
Thanks Steve,
I think I'll go for the 1.2mm then. I may order some short lengths to try out the bends before getting the final longer lengths to fit to the car.
I measured the pipes near the radiator with some calipers and they measured 35mm. That's why I searched for 35mm tube.
Andy
 
You might look for annealed stainless pipes. MUCH easier to bend and work with. Alternatively you can anneal the pipe yourself, but it doesn't always work as well as the pre-annealed stuff. Actually the thicker wall may bend (and weld) better than the thin wall. Likewise seamless pipe will be less prone to failure when bending it. Regardless you should have it mandrel bent on the appropriate equipment. Or if you are very skilled at welding stainless then another approach is to buy pre-bent sections and cut/join them to make the shapes you want.
 
I notice you both refer to the hollow round section to be used for this application as "pipe" whereas I refer to it as "tube"

Most people they would use the term interchangeably, but to an engineer they are very different.

Pipe is measured by it's internal diameter, pipe wall thickness is determined by the schedule of the pipe, so outside diameter of the pipe is I.D + (2 x wall thickness)

Tube is measured by it's outside diameter, the wall thickness of tube is called it's material gauge. ID of a tube is O.D - (2 x W,T.)

I have some old X19 water tube sections out behind my shed that I cut out of the lemons race car, I'll take a picture in the morning to show you the neck down point, right here it exits the tunnel whee the drain points are, you can see the welds on the tubes at this point.

Usually people would buy an exhaust "donut" and cut the sections out to use as needed, as tube can "sausage" and narrow down quite a lot when you bend it on a regular tube bender (with no internal mandrel) ....

I have managed to get really nuice bends in thin wall tube by taping the end of sections, filling them with water, then standing them up in a chest freezer and letting it freeze... then bending the tube while it had a solid frozen core inside, worked almost as well as a mandrel bender.

SteveC
 
He is referring to exhaust material, which in America is called "pipe". And traditionally it is pipe, measured by the ID. However it can come as either pipe or tube (sized by ID vs OD) depending on the supplier, material and application. This is often confusing but the norm here is still to call it "pipe". Similarly here the thickness of exhaust pipe is measured in "gauge", like sheetmetal, and not commonly referred to as "schedule".
 
Dr.Jeff said:
He is referring to exhaust material, which in America is called "pipe". And traditionally it is pipe, measured by the ID. However it can come as either pipe or tube (sized by ID vs OD) depending on the supplier, material and application. This is often confusing but the norm here is still to call it "pipe". Similarly here the thickness of exhaust pipe is measured in "gauge", like sheetmetal, and not commonly referred to as "schedule".
Click to expand...
Depends on if you are in the industry and developing products. We use tubing and it is called out by outside diameter and wall thickness aka gauge.
 
kmead said:
Depends on if you are in the industry and developing products. We use tubing and it is called out by outside diameter and wall thickness aka gauge.
Click to expand...
Exactly. Traditionally the automotive exhaust industry in the US has utilized pipe sizing (hence the common expression "exhaust pipe" for cars). But I've noticed that has been gradually changing as suppliers from around the world are being used - particularly for certain metal types.

In regard to the use discussed in this thread (X coolant transfer from the rear to the front), another common option for retrofitting is copper from the plumbing industry. And that is another anomaly; in the US it is usually sized by the ID ("pipe"), but in Europe it is sized by the OD ("tube"):
en.wikipedia.org

Copper tubing - Wikipedia

en.wikipedia.org en.wikipedia.org
 
Thanks Steve,
I was thinking of filling the "hollow round section" with dry compacted sand instead of water. I don't have a 3-4m long freezer to fit the tube/pipes in.:)
Why would they have changed the diameter along the length of the run?
Andy
 
I once had to straighten out some aluminum tubing (tree branch fell on large antenna) and used the dry, compacted sand approach. It worked perfectly and allowed me to unbend the bends to the point they were no longer detectable. However, getting the sand out was way harder than I thought it would be.
 
Sand bending can be an artform...

when I was young I got to watch an old Italian guy, John (Gianni) Derietta hand sand bend some extractor pipework for an open wheeler race car, a bag of curling snakes, each made as one piece (not cut and sectioned) with mutliple compound bends in all directions...

I only spent a few hours wacthing, but he'd fill the tube with dry sand... use an arbor press to really compact the sand, braze end caps onto the pipe (like a core plug cap) and then he would heat sections with a large propane torch, and clamp then bend around various daiameters of large pipes (like 12 / 16 inch diameter) set standing up .... the material would form perfect curves, but very slowly.

when he was done he just cut the bent section of tube where he wanted, the sand ran out, and there was one of the extractor tubes perfectly copied, by hand and by eye.... he was an older guy in his 50's (this was 40 years ago) so I doubt he's still around.

@lidox19 I didn't have a 3m long chest freezer either, I did 800 or 900mm lengths standing up, to build a turbo exhaust system in 3" for a rally car ... it was just to show that there are alternatives to a solid mandrel
20210415_083927.jpg
there's a join just inside the tunnel section, not saying they use a different tube size from there forwards, but they dont make them as one piece... and 35mm OD will be a very tight fit to get your hoses on , try it , so they kinda have to neck them down at the very ends at least before swaging in the lip. I've had to work on a few X19's that have had the pipes replaced, and there are times getting hoses on can be a chore, and I've seen plenty of cut and nicked hoses caused by the replacement pipework

an exhaust place with a good tube bender, they will have a fitting to re size the OD of the pipe down a fraction. Like an internal conical affair that you push over the end and lets you size the OD of pipe down to become ID, sized so it fits inside it's original ID

SteveC
 
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Dr.Jeff said:
You might look for annealed stainless pipes. MUCH easier to bend and work with. Alternatively you can anneal the pipe yourself, but it doesn't always work as well as the pre-annealed stuff. Actually the thicker wall may bend (and weld) better than the thin wall. Likewise seamless pipe will be less prone to failure when bending it. Regardless you should have it mandrel bent on the appropriate equipment. Or if you are very skilled at welding stainless then another approach is to buy pre-bent sections and cut/join them to make the shapes you want.
Click to expand...
Like my stainless steel coolant pipes. Mandrel bent by a local stainless steel exhaust system supplier. Then supplied for me to fit into cavity fir covering with fabricated cover.
 
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