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Steel Pipe Thickness

Posted: Tue Dec 11, 2007 5:27 pm
by pat123
I have a quick question, sch is a thickness rating right? so sch 40 steel would be the same thickness as sch 40 pvc? I am thinking about making a steel gun after i finish my current piston valve and the only steel pipe i can find is not as thick as sch40 pvc. does anyone know what pressure this pipe can be taken to? thanks

Posted: Tue Dec 11, 2007 6:04 pm
by MrCrowley
I doubt the metal would be the same thickness as the PVC.

I would think the schedule system applies to it's material, with PVC sch40 is probably the least thick scheduled PVC you can get, but with the metal since it's stronger it doesn't need to be as thick as PVC. So the smallest thickness of scheduled metal is probably sch40, but would be thinner then the PVC because metal is stronger then PVC.

Confused? Well that's what I would think it would be like anyway.

Posted: Tue Dec 11, 2007 6:50 pm
by DYI
Schedule applies to all pipes, regardless of material. Sch 40 2" steel is exactly the same dimensions as Sch 40 2" PVC. If it isn't as thick as Sch 40 PVC of the same diameter, then it is either
a)SCH 10
b)not pipe, but tube

Posted: Tue Dec 11, 2007 7:40 pm
by MrCrowley
Hmm my steel pipe I got from America doesn't seem to be the same thickness, maybe i'll get out my calipers and check it.

Posted: Tue Dec 11, 2007 7:46 pm
by JDP12
check mcmaster.com they give you wall thickness of pipe. steel will almost always be thinner than PVC, and be able to take the same pressure. You'll be totally safe using it, i forget what Fnord took it to with his hybrid test, but it was over a 1000 psi i believe and it didn't rupture

Posted: Wed Dec 12, 2007 9:36 am
by SpudFarm
fnord was using 11x in a closed chamber

Posted: Wed Dec 12, 2007 9:43 am
by Fnord
I know that metal pipe varies in thickness from pvc, as a piston I made for one didn't fit in another. I was kind surprised because I thought they would be the same, but apparently not.

Posted: Wed Dec 12, 2007 12:01 pm
by clide
The schedule defines a minimum wall thickness and the outside diameter. It might also define a maximum wall thickness, but I'm not sure about that.

The wall thickness for steel pipe is usually closer to the minimum wall thickness than PVC, but you could always have a thinner piece of PVC that is SCH40 or a thicker piece of steel that is SCH40. It all depends on the manufacturing. Even from one piece of PVC to the next the ID is very inconsistent.