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• PVC is specifically NOT designed for compressed air. Under pressure PVC can explode launching sharp shards every direction!!! This is why it is not used to plumb shops for compressed air.

  Posted by: issfab@gmail.com on February 1, 2007 at 9:00 AM

• oh please, read the side of the tube. But you're right, when it does fail, it fails with shrapnel. A better alternative is ABS - which fails by distortion. I've built pneumatic cannons out of both materials - I'm more comfortable with ABS, but nothing of mine has failed after years of use and a little abuse.

  PVC isn't used for shop air because of the service life. Over time the elastomers in PVC disappear making the pipe very brittle (which isn't a problem for house drainage). UV exposure doesn't help. And when you're buying a shop air system, you want a long life ;)

  The pipe won't know the difference between fluids - air or water ;)

  Posted by: trebuchet03 on February 1, 2007 at 9:22 AM

• I like the author prefaces the article by stating he won't give out the plans.

  Yeah. Like it's a super secret.

  Quiet. Let's hope someone doesn't let the Chinese know, or we're all screwed.

  //Thanks for the information on pipe failure issfab and tebuchet03. I wasn't aware that ABS just deforms. Good tip to know.

  Posted by: Tercero on February 1, 2007 at 1:27 PM

• OSHA says it is not safe

  Posted by: issfab@gmail.com on February 1, 2007 at 1:27 PM

• Not safe? no kidding!

  Please remember to wear eye protection when operating you plywood shattering potato gun. In the mean time, I'll resume working on my home made flame thrower. Safe!

  "You're gonna take somebody's eye out little Jimmy!"

  Posted by: tms10000 on February 1, 2007 at 4:19 PM

• doesnt he just look like the happiest sonuvabitch on the face of the planet

  Posted by: kylenstevo on February 1, 2007 at 5:08 PM

• hehe... that's why ASME says (in the same OSHA report):

  the above ground portion of the plastic service line is completely enclosed in a conduit or casing of sufficient strength to provide protection from external damage and deterioration.

  (emphasis added)

  Again, PVC is fine for compressed gas for things that are not permanent installations over long periods of time. It's cheaper than the recommended ABS systems which is why construction companies would use it. Additionally, a pipe used on a construction site (or even home workshop) will see many more fatigue cycles ;)

  From that same document:
  

  Only one type of plastic pipe has been approved for use with compressed air. That pipe, Acrylonitrile-Butadiene-Styrene (ABS), is marked on the pipe as approved for compressed air supply.

  Tercero, no problem ;) There's photos out on the internet somewhere - basically put a PVC pipe under a towel and hit it (hard) with a hammer. Repeat for ABS ;)

  Posted by: trebuchet03 on February 1, 2007 at 5:18 PM

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