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Cell Core PVC

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Cell Core PVC

Unread postAuthor: stevethecat » Wed Jan 03, 2007 9:57 pm

Hello, I built my first spud gun yesterday. Its a simple combustion gun, and i was pretty proud of it.

I was going to test it today after work, but when reading the wiki on this sight i saw that you should never use cell core pvc because it cant take any pressure.

I got to thinking about my gun and, as luck would have it, about 3 inches worth of my 13 inch chamber is 4 inch cell core pvc.

I intended to rebuild the gun, but when i went back to lowes today and, everything bigger than 2 inch pvc is either very thin wall, or its cell core.

So i have 2 questions for you guys.

1. Where can i find sch-40 pvc over 2 inches.

and

2. Would it still be ok to use the gun i made even with the cell core portion? Arent combustion guns pretty low pressure compared to everything else, or do they still make to much pressure for cell core?




PS: I didnt let this little setback deter me. Since i couldnt find the parts i wanted, im decided to make an over/under style combustion gun with 2 inch pipe as the chamber and 1.5 inch pipe as the barrel.

Its going to have about a 40 inch barrel and a 34 inch chamber, that should give the chamber about 106 cubic inches of volume and a 1.5:1 chamber to barrel ratio.

Its not the 150 that the other gun had in the chamber, but at least theres less chance of exploding. (and thats always a nice point)
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Unread postAuthor: pyromanic13 » Wed Jan 03, 2007 10:14 pm

cell core... I'd go for it with a combustion...
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Unread postAuthor: Canuckicks » Wed Jan 03, 2007 10:26 pm

Cell core should be fine for a combustion gun but just for peace of mind i would cover your gun in some duct tape or another adhesive so that if it does fail there is some protection from the flying PVC shards (this is known not to be very effective but it is still worth it) your new gun sounds good but the small diameter chamber will make it hard to fill and ignite properly
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Unread postAuthor: jjjd » Thu Jan 04, 2007 12:04 am

duck tape Does Nothing! people always say something like that, just wrap it. it will not help at all, and yeah i would do it with what u got, and if u are looking for the sch 40 pvc order from www.Mcmaster.com(only if u live in the states,im in canada and they dont ship here)
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Unread postAuthor: MrCrowley » Thu Jan 04, 2007 12:11 am

or you could put an old jean leg over the cell core partion,it wont do alot but it could save your eye or you getting a flesh wound if it blows.
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Unread postAuthor: stevethecat » Thu Jan 04, 2007 7:20 am

Thanks for the help guys.

Ill mount the igniter on the gun today after work and hopefully get some pictures up.
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Unread postAuthor: frankrede » Thu Jan 04, 2007 6:23 pm

cell core if perfect for combustiuons dont listen to them they dont know wat they are talking about.
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Unread postAuthor: Pete Zaria » Thu Jan 04, 2007 6:27 pm

We need to know if it's cell core PVC or cell core ABS.

Cellular core PVC will shrapnel if it explodes, and since it's cell core, it's more likely to blow anyway.

Cellular core ABS isn't a problem - I've personally tested it to over 125psi without failure. When it's made to fail (at over 150psi in my case) it doesn't grenade and shrapnel at all, it rips open clean lengthwise down the pipe.

Peace,
Pete Zaria.
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Unread postAuthor: frankrede » Thu Jan 04, 2007 11:32 pm

Its cell core pvc, hence the writing and topic name.
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Unread postAuthor: mark.f » Fri Jan 05, 2007 6:45 am

Just do yourself a favor and get some solid core pipe. May cost a little more, but at least you'll feel safe shooting in chilly weather, (I've used my solid-walled PVC guns below 40 degrees fahrenheit). Also, it's too much of a structural hazard! The pressure might not break it, but stress from the weight of the barrel or slight impacts could spell the end of this gun.
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Unread postAuthor: stevethecat » Fri Jan 05, 2007 8:32 am

Ok, i put the ignition system on and shot the gun once last night (would have been more but its to loud for that time of night).

Thankfully nothing exploded.

Cold weather really isnt a problem, even this time of year. I live in midwest GA and besides the occasional odd cold snap days, it doesnt really get all that cold. There have only been about 5 days so far this year that i couldnt wear a t-shirt outside.
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Unread postAuthor: benstern » Fri Jan 05, 2007 2:19 pm

Go to the local ace hardware to find pressure rated pipe and fittings up to 4"
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