Use PVC pipe for pressure vessel?

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randyrls

randyrls

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I read somewhere that PVC pipe can be used for a vacuum chamber. After "allegedly" thinking about this. I checked out the specs for PVC pipe. It appears that the operating pressure rating for schedule 80 pipe is from 80 to 140 PSI and It comes in sizes up to 12".

I wonder if this would be used for pressure casting?

Has anybody tried this?
 
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While true, why take a risk. A few around here have seen some pretty scary pressure pot failures particularly when modified. What ever small savings there could be, its not worth it. Use one that is certified. The numbers may not be scary, but even 20 or 30 psi can cause major damage under the right conditions.
 
IF you were going to use PVC - get waterworks "DR" rated pipe - lowest pressure class is 165psi, highest that I know of is 305psi.

keep an eye on construction sites and ask for cutoffs. The pipe should be easy to come by, fittings can be obtained from HD Supply or other supply houses - but they are expensive.
 
You are not supposed to use pvc pipe for compressed gasses. If it ruptures it shatters and creates shrapnel or so I understand. A lot of people use it for compressed air lines though, I don't. I would stay well below it's rated pressure.
 
I have built a pneumatic potato gun where the "tank" held quite a bit of pressure. I think if I were to build a pressure pot out of PVC, I would fiber glass the outside just to add a little more strength.
 
I have to agree that it is only good for the vacuum chamber. Every maker and seller of all PVC pipe even the DR grade clearly state that it isn't to be used for any form of pressurized air/gas flow.

I can state that it does shatter nicely, Luckily it was when the shop was not in use. And despite the printed info which is a standards reference regulation. As mine let go under 100#'s. It also tends to let go after a length of time at any glue joint that isn't cleaned and primed perfectly.

One of the reasons is the wall thickness varies along a section of pipe you can see the undulations looking inside.

And people do use it all the time for air lines, heat cold, UV(since most doesn't have UVray protection. Shook damage for a bump or strike, to tight of clamps holding to a wall all can cause it to failure at some time.
You can google pvc pipe pressure failure, There are lots of stories some with photo's and there have been injuries and a fatality or two
:clown:
 
Potato gun trick to stop as much shrapnel as possible

Wrap the pipe in duct tape then a tough flexible fabric like old jeans or canvas.

Disclaimer: I would not use PVC as a pressure pot. In a potato gun the pressure is not left in for very long.
 
A good thing to keep in mind is ANY system is only as strong as it's weakest link. Pipe can be rated to 1,000 psi for all that matters. If the fitting joints can fail at 50 psi, then that's your danger zone. If the fittings are done by the consumer ( i.e. us at home ) there is no guarantee that you will get as high a rating as a commercially built ( and tested ) system...
 
Even if PVC is able to withstand the pressure, I don't see it holding up to repeated pressurization cycles without a failure somewhere.
 
I made a small pressure chamber out of 1 1/4 galvanized pipe. I just leave it hooked up to the compressor because it has a regulator and if there is a leak the compressor will turn on and keep the pressure up.
 
I'm glad you came to that choice Randy. A friend of mine tried this and it wasn't pretty. PVC rating is fluid pressure, not air. It took me 6 months to find my pot on CL, but Grizzly has a quality pot for about $85. I know there are big fans of HF pots...and they are welcomed to it.
 
Hi,

New guy on the block. I have a pressure pot for my pressurized stuff, but want to make a separate 3 tube vacuum system for stabilization. So is PVC stable enough for this and if so, am I looking for a certain rated PVC?

Mike B
NH
 
Sewer and drain line is used. for the vacuum chamber 6" and above with silicone seals for the gaskets and lexan for the bottom and top plate with a valve to release the vacuum,and an inlet valve to shut off the vacuum pump source.
:clown:
 
Don't use drain pipe for vacuum. It isn't strong enough. Schedule 40 or Schedule 80 is recommended by Joe Woodworker for his build it yourself pumps. Mine draws only 24-25". There is some question if that is enough vacuum.
 
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