The True Power Of A Piston Valve

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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MrCrowley
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Mon Oct 22, 2007 1:29 pm

Some French guy discovered PVC, but it was an American who turned it into a plastic. Though some German dude first turned it into a commercial product.
Gepard
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Mon Oct 22, 2007 2:03 pm

How do you turn PVC into a plastic? Surely it already is.......
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MrCrowley
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Mon Oct 22, 2007 2:12 pm

PVC is a polymer I think.
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pvcmaster
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Mon Oct 22, 2007 2:28 pm

I'm glad youre all right. Is that the gun from the instructables contest?

Oh, if I were testing a temporary setup on one of my cannons, I sure as hell wouldnt take it to 95 psi.
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ALIHISGREAT
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Mon Oct 22, 2007 2:44 pm

pvcmaster wrote:I'm glad youre all right. Is that the gun from the instructables contest?

Oh, if I were testing a temporary setup on one of my cannons, I sure as hell wouldnt take it to 95 psi.
yes but if he took it to around 30psi and it was fine then he pumped it up to 120psi because he was confident it would work... it could have been a whole lot worse.

Now on the other hand MrCrowley you could have tested it at 30 then 40 the 50psi etc. instead of taking it to 95psi straight away.
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Mon Oct 22, 2007 3:34 pm

I test all my things at 125psi first time.....if you use water there's no risk and you can cycle the pressure much quicker which increases the shock to the materials.
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ammosmoke
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Mon Oct 22, 2007 6:49 pm

PVC stands for polyvinylchoride. So, um, yeah it is basically a polymer. IDK how this couldn't be a plastic when put together, but I'll leave that to you.

@Gepard Increased shock isn't such a great idea, as it weakens the gun for the next time you use it. Although, what you are describing probably isn' that big a deal.

@McCrowley
Well, um, I am pretty sure that any fitting would have failed there unless it was sch80 or something. I mean, how many guns would you hear about breaking if our fittings were crappy?
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Marco321
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Mon Oct 22, 2007 9:41 pm

Ammosmoke is right, it is a polymer.
MrCrowley wrote:Some French guy discovered PVC, but it was an American who turned it into a plastic. Though some German dude first turned it into a commercial product.
I think what MrCrowly mean is that PVC was first discovered by some French guy. But pure PVC has no real use in industry (apart from piping and such) because of its properties (hard and brittle). Additives are added to make it usable (such as use in insulation on copper wires), which is probably what the American guy did to turn it into a 'plastic'. The German dude probably started making it commercially or something.

If I'm wrong someone correct me, but its what i remember from Chemistry when we did polymers.


EDIT: Thats unfortunate what happened to your gun, hopefully she will be up and running soon.
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The 7 P's - Proper Prior Preparation Prevents Piss Poor Performance
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MrCrowley
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Mon Oct 22, 2007 9:49 pm

Marco321 wrote:Ammosmoke is right, it is a polymer.
I said PVC was a polymer, ammosmoke said it was a plastic, which a polymer practically is. I was trying to say PVC isn't always in the pipe plastic form.

Anyway I took it to 95psi after I had done two shots at 50psi.
When I said it was a test setup I meant I knew the piston worked, but was just seeing how much difference a sprinkler valve had performance wise, there's no reason I shouldn't take 260psi rated pipe to 95psi.

Of course any fitting would fail, i'm not blaming this on the PVC, it was my fault for not having an addiquit(sp?) bumper, nothing to do with PVC and compressed air, just that the piston had so much force pushing it back.
ammosmoke wrote:@McCrowley
Well, um, I am pretty sure that any fitting would have failed there unless it was sch80 or something. I mean, how many guns would you hear about breaking if our fittings were crappy
Ummm did you completely miss the sarcasm and the 'just kidding' in my post?
MrCrowley wrote:Just thought i'd mention the fittings that 'failed' were bought in America

Just kidding. I still got the recipet, wonder if they accept international returns
And by the way its MrCrowley

I've had fittings (from a NZ hardware store) rated to 260psi fail at 110psi, PVC isn't meant for compressed air, simple as that. So I wouldn't see how you thought I was being serious saying American fittings are crap, as you can see so are NZ fittings.

By the way, my stand with the whole 'pvc isn't meant for compressed air' thing, is that the company just doesn't want to be sued if it does blow, because pressurized water in PVC almost has no high speed shrapnel flying at you when it goes boom, unlike PVC with just compressed air.

And yes this was on the instructables site.
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ammosmoke
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Mon Oct 22, 2007 10:18 pm

Okok MRcrowley, its all good. I wasn't really that pissed, just a little bothered. Although, it appeared that I was mad in my post, I was kinda joking too.

But seriously, this WHOLE time I thought it was MCcrowley LOL!!!
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MrCrowley
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Mon Oct 22, 2007 10:35 pm

I know everyone thinks it's McCrowley, well a lot of people do anyway.

I know it's a hard thing to change, you mis-read someones name and after awhile to you that is their name and you always think of that person as that name, anyway yeah, maybe I should get PCGUY to change it to Mr. Crowley :P
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Mon Oct 22, 2007 11:22 pm

MrCrowley wrote:I know everyone thinks it's McCrowley, well a lot of people do anyway.
Dammit i don't have time for this! :D
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ammosmoke
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Mon Oct 22, 2007 11:47 pm

Huh? (message too short)
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MrCrowley
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Mon Oct 22, 2007 11:53 pm

Ha! Nicve one JSR :lol:

Is that top half Aleister Crowley? I haven't seen that pic of him before, not that I like the guy or anything. Interesting dude but my name is purely from the Ozzy song written about him.
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Marco321
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Tue Oct 23, 2007 12:11 am

MrCrowley wrote:Ha! Nicve one JSR :lol:

Is that top half Aleister Crowley? I haven't seen that pic of him before, not that I like the guy or anything. Interesting dude but my name is purely from the Ozzy song written about him.
I know where it came from :P
Ozzy is coming to Australia in March, I'm hoping to get tickets for it and for iron maiden. But its looking like i will only be able to go to one... :(
Failure to plan is planning to fail.

The 7 P's - Proper Prior Preparation Prevents Piss Poor Performance
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