9 replies to this topic

[ChIck3n]

So I just grabbed some 1/2" PVC for a simple blowgun from Home Depot. When I tested it out it worked OK, but the darts (taggers and whistlers) would slide out the barrel if angled down. I've seen others with blowguns where the dart would stay in place when moved around. Does PVC have a variable inside diameter, where I should just bring a dart and try a bunch of pieces until one fits right? Ir is there a specific type of pipe I should look for?

[snakerbot]

Does PVC have a variable inside diameter?

Yes. Only the outside diameter of pvc is specified, so the inside diameter can vary from piece to piece or even within the same length.

[zx532]

Yes. Only the outside diameter of pvc is specified, so the inside diameter can vary from piece to piece or even within the same length.

That explains quite a bit, are there any known ways to solve this issue? (like, say for a CPVC barrel?)

[Nerfomania]

That explains quite a bit, are there any known ways to solve this issue? (like, say for a CPVC barrel?)

No. That is just how PVC is, unless you own a lathe (and even then) there is not much to do.

[BOSS9]

You just have to test everything. I always keep a couple darts in my backpack for when I go to the store.

Variable inner diameters can be awesome if you know what you're looking for. I have springer CPVC, airgun CPVC, tagger PVC, and PVC that nests CPVC with varying tightness. I even have two batches of 1 1/4".

[ChIck3n]

Ah, thanks! Guess it's back to the store tomorrow to sift through their piles of pipe.

[Zorns Lemma]

Pipe is made to specific outer diameter, with a tolerance, since the primary purpose is to carry stuff (plumbing, etc) and only a fairly fixed OD will allow the fittings to join pipe together.

Inner diameter is generally the same, since the pipe rating specifies a minimum wall thickness, and the less material you can get away with using the better, so they generally are around that minimum thickness, but there will be a lot more variance.

Pipe with SDR rating gives a specific ratio of wall thickness to outer diameter, giving you a better estimate for what they are aiming for on the inner diameter, but again, this specification is for safety rating for pressure tolerance, and the only dimension that has to "fit" is the OD.

If you want precise ID, look into tubes, which are made to tolerance on both OD and ID.

[proplus]

It can also br different is on which brand of pvc it is.
JMeagle and silverline pvc pipe are probabily the most consistant and charrlotte pipe which is used by most east coast nerfers.
While Valencia pipe has an awful pipe consistancy

Edited by proplus, 12 July 2012 - 02:42 PM.

[KaneTheMediocre]

Steel EMT conduit is of a slightly looser and more consistent fit for taggers and their ilk. It can be easily nested in thinwall PVC to work with PVC couplers--You need a mouthpiece that will protect you from the EMT.

[Draconis]

It can also br different is on which brand of pvc it is.
JMeagle and silverline pvc pipe are probabily the most consistant and charrlotte pipe which is used by most east coast nerfers.
While Valencia pipe has an awful pipe consistancy

The strangest combination is the Urmahm brand, which has by far the largest inside diameter of any comparable tube, while simultaneously having the thickest walls.

Also, OD must be difficult to maintain as well, given that Venom has that whole batch of 1" with the too narrow diameter.