quick question

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
jon_89
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Wed Mar 26, 2008 11:03 pm

I got a 7 foot piece of 1.5 inch abs and would would like to use it for my barrel but it is cell core. Does this matter for a barrel?
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Hubb
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Wed Mar 26, 2008 11:04 pm

It will be fine for a combustion.
jon_89
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Wed Mar 26, 2008 11:05 pm

Ok thanks for answering so quick.
spudman029
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Thu Mar 27, 2008 11:46 am

As long as it is for the barrel, you will be fine. But please for the love of whatever religion you believe in, do not use cell core for the chamber.
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SpudFarm
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Thu Mar 27, 2008 11:58 am

celluar core can be used in a basic...
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Thu Mar 27, 2008 4:31 pm

as stated before this should be fine for a barrel as it does not recieve the brunt of the combustion

in a chamber it could be dangerous though
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jimmy101
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Thu Mar 27, 2008 7:50 pm

Davedom6766 wrote:as stated before this should be fine for a barrel as it does not recieve the brunt of the combustion
I heard people says this before and it makes no sense at all.

The barrel behind the spud is exposed to the exact same pressure as the chamber is. You can't use a lower pressure rating pipe for the barrel and expect it to hold up.

Cell core might be OK for a combustion, but it doesn't matter if you are talking about the chamber of the barrel, they both get exposed to the same pressures.

Heck, you could probably argue that the stress on the barrel is greater than on the chamber. There is a big-ass pressure gradient across the ammo. So the barrel has to deal with having 60 PSIG (or whatever) at one place in the pipe and ~15 PSIG just a couple inches away.
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DYI
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Thu Mar 27, 2008 7:54 pm

I wouldn't use cellular core PVC for a barrel on anything at all. Because the "big-ass pressure gradient" that Jimmy mentioned doesn't combine to well with the hazardous* failure properties of PVC.

Where did you find cellular core ABS anyway? The only stuff I can get around here is solid wall - I'd have to travel 5 hours away to get cellular core walled pipe if I wanted it for some reason.
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Jared Haehnel
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Thu Mar 27, 2008 7:55 pm

Hey Jimmy or who ever else reads this...
Say I had a hybird made of metal pipe. The optimal barrel length was 20 feet. Would I be safe using metal pipe for the first bit of the barrel and then switch to the cheaper scedral 80 or 40?
My intuition says yes since the pressure lessens the further down the barrel the object goes due to expansion of the gasses. But I figured y'all might have some insight...
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jon_89
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Thu Mar 27, 2008 7:57 pm

Well I was under my house running cable and found it awhile ago. There was also some one inch pvc that I used for my pneumatic. Though I finally pulled it out to do something with it.
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jimmy101
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Fri Mar 28, 2008 3:35 pm

Jared Haehnel wrote:Hey Jimmy or who ever else reads this...
Say I had a hybird made of metal pipe. The optimal barrel length was 20 feet. Would I be safe using metal pipe for the first bit of the barrel and then switch to the cheaper scedral 80 or 40?
My intuition says yes since the pressure lessens the further down the barrel the object goes due to expansion of the gasses. But I figured y'all might have some insight...
Jared-
A gun really should be designed to take the maximum possible pressure that it might experience. In other words, the design should be able to handle the pressure if the round jams in the barrel. The chamber and entire barrel length should be able to handle that pressure.

It is too dangerous to design a gun any other way. If it fails you are going to be in a world of hurt. If it is a hybrid, it'll hurt even more.
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Bluetooth
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Fri Mar 28, 2008 4:02 pm

Wow!!! Thats a lot of new people since I was last on here. If I were you, I wouldn't use cell core, but some people say it is ok for the barrel.
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scottcrete
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Fri Mar 28, 2008 4:10 pm

thats what i am talking about.. i do weird stuff like that too lol... use what i can find.. and dig in the dumpsters. for what i dont have at home... lol.. you will be amazed what you can get at lowes dumpster..

Is there anything wrong with dumpster diving? if you ask first?
one time when i lived in Beckley.. staples was remodeling their store. and i got 55 sheets of peg board.. and as many shelves as i wanted..

not that this is relavant to your pipe situation.. other than you found it under your house..

sorry for rambeling
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Spuddin
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Fri Mar 28, 2008 4:20 pm

bro i would not use cell core for a barrel. and scott, there is nothing wrong with dumpster diving, i have earned my dd degree long ago and found so much cool stuff.
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Fri Mar 28, 2008 4:22 pm

If there weren't dumpsters, I would be a poor man right now. (as i would have to actually buy all my stuff)
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