PNeumatic Innertube lining

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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AnotherSnappedLine
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Tue Feb 22, 2011 10:57 pm

As we all know, pvc can be explosive under the right pressure; has anyone ever tried lining the inside with an innertube of some sort? Therefore, if the pressure limit is exceeded, the pvc can crack but not explode. :idea:
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ilovefire
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Tue Feb 22, 2011 11:39 pm

if the inner lining cant hold the pressure then both will explode, if it can, why not just it as the chamber
why make it if it dosent shoot?
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Crna Legija
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Tue Feb 22, 2011 11:45 pm

yea i think your better off just getting stronger pipe
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nadjatee1996
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Tue Feb 22, 2011 11:59 pm

On a little unrelated topic, what happens if I got overboard on a METAL pipe?
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jackssmirkingrevenge
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Wed Feb 23, 2011 12:58 am

nadjatee1996 wrote:On a little unrelated topic, what happens if I got overboard on a METAL pipe?
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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ilovefire
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Wed Feb 23, 2011 1:01 am

nadjatee1996 wrote:On a little unrelated topic, what happens if I got overboard on a METAL pipe?
well it rupture, explode or whatever you use as endcaps of joints give out, whatever happens it would be pretty
why make it if it dosent shoot?
nadjatee1996
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Wed Feb 23, 2011 1:03 am

I was kinda wondering if it'll just go BOOM
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cfb_rolley
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Wed Feb 23, 2011 1:41 am

inner tube lining might be unreliable, sometimes with bmx tyres, the tyre (even if it has kevlar underlay) can tear before the tube does, other times the tube can tear randomly (usually near the seams). So i wouldn't count on it. Sorry bud, but the easiest option for making a cannon safer is to use rated pipe, and not exceed the rating of the weakest part.
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AnotherSnappedLine
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Wed Feb 23, 2011 6:55 am

I figured it wouldn't work, just wondered if anyone tried something like it.
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Gaderelguitarist
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Wed Feb 23, 2011 1:13 pm

The closest I think I've seen is people reinforcing the outside of their pipes with wire mesh, cloth, resin, duct tape, etc.

The only chance of your PVC exploding is if you pressurise it too high, or if it is too cold and therefore brittle. These are two things that are easily avoided with the necessary common sense that comes with this hobby. Don't exceed the pressure rating on your pipes, and don't shoot plastic cannons in the winter unless you want to be injured.
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DYI
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Wed Feb 23, 2011 3:45 pm

The only chance of your PVC exploding is if you pressurise it too high, or if it is too cold and therefore brittle.
From what I've seen, the majority of PVC launcher failures occur as a result of PVC's very low impact resistance (toughness) - it's brittle by pressure vessel standards at any reasonable temperature, thus the ban on using it for compressed air lines. Most failures stem either from excessive recoil, "fast" pressure spikes, piston impacts, and poor design causing recoil to snap off fittings.

If the only PVC component is a tube, then reinforcing it through a thick fiberglass wrap is fairly easy, and effective. Unless you're willing to do something like putting the whole assembly inside a larger pipe and casting the space full of urethane or resin though, the fittings remain a weak point. PVC cannons have appeared to be in decline recently, and for good reason.
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Wed Feb 23, 2011 4:00 pm

The issue of safety was discussed in some detail in this thread, useful read.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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