Shot Results! First Air Cannon./any ideas on how to improve?

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.
Matt221985
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Mon Jun 04, 2007 11:30 pm

This is my first air cannon.

Air tank-3inch pvc 2 ft long
Barrel-1 1/2 inch pvc 5ft long\
Still need to add ball valve and im already to go...Updates once its finished. Any ideas are welcome..


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Last edited by Matt221985 on Wed Jun 06, 2007 11:36 am, edited 4 times in total.
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hi
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Mon Jun 04, 2007 11:40 pm

welcome to the fourms. i hate to say this, but you used DWV. you need to get pressure rated fittings. other than that it looks excellent.

your fittings need to say (nsf-pw) right now they say (nsf-dwv) just change that before you glue it and it will be perfect. if you did glue it then dont take it above 60 psi or so.

i would also like to suggest a barrel support. it might get a little wobly with out it. again, i looks great, just get new fittings.

edit- another thing you may or may not want is a compression union, that way you can screw tha barrel on and off and have it as a breech loader.
Last edited by hi on Mon Jun 04, 2007 11:42 pm, edited 1 time in total.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
Matt221985
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Mon Jun 04, 2007 11:42 pm

what fittings should i replace? on what end? they were marked PVC
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hi
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Mon Jun 04, 2007 11:44 pm

i know that they are pvc, it just a low grade pvc thats all. the two elbows and the reducer need replacing. they will say nsf-pw on them.

you dont have to change them, but for safty reasons i would. you can take it to much higher pressures if you do get new ones, thats all.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
Matt221985
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Mon Jun 04, 2007 11:47 pm

well, prob too late now, all glued together, except the barrel

was looking to get up to 90 psi out of it
Last edited by Matt221985 on Mon Jun 04, 2007 11:49 pm, edited 1 time in total.
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noname
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Mon Jun 04, 2007 11:49 pm

It's never too late to be safe with something. Cut the DWV fittings off and get pressure ratings, you'll be happy you did later.
Matt221985
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Mon Jun 04, 2007 11:50 pm

ok, so what would go wrong with these fittings if i use whats on it now?
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hi
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Mon Jun 04, 2007 11:53 pm

it really worth it. you built a great cannon, you gust have a few bad parts. thats all. this is what happens at around 90 psi.


[youtube] [/youtube]
Last edited by hi on Mon Jun 04, 2007 11:54 pm, edited 1 time in total.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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noname
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Mon Jun 04, 2007 11:54 pm

They have a very short socket depth, and will blow off eventually. The way this cannon is built, you'll be hit by a pound or so of very fast moving plastic pipe fittings. You can use them, but don't take it over 50 psi.
Matt221985
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Mon Jun 04, 2007 11:57 pm

ouch! what blew up in that video? cant really tell
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hi
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Tue Jun 05, 2007 12:02 am

a reducer.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
Matt221985
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Tue Jun 05, 2007 12:07 am

ok, so where can i get high pressured pvc fittings? bought mine at home depot, dont know if they have high pressure fittings, should i replace the 3 inch one too thats on the tank?
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hi
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Tue Jun 05, 2007 12:46 am

the end cap is fine where it is, you just need a new reducer ( it looks like you need two accually) and the two elbows. i didnt know that home depot had 3'' pvc pipe. they should have it there if they have the pipe, but if not then a plumming store will have it. you need a bushing, not a bell reducer. if it looks like a bell then it is probably dwv, but if it is a bushing then it is nsf-pw.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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MrCrowley
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Tue Jun 05, 2007 12:58 am

Is the chamber even Pressure rated?

So far you need to replace:

Reducer x 2
Elbow x 2

and any other non-rated pipe we can't see.
Matt221985
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Tue Jun 05, 2007 1:04 am

yes, the chamber is rated for 350 psi and the barrel is rated for 120 psi, i washed off all the lettering so thats why u cant see it...

As "hi" was saying i shouldnt go over 60 psi becuz of my fittings, if i were to use it at 60psi with the fittings already on there..how much power would i get from 60 psi out of a cannon this size? enough to throw a spud 200 yards or so?
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