First Pneumatic Cannon

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
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RabidDuck
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Hey there guys. This is my first Pneumatic Cannon i've made.
I used a 1 inch modified sprinkler valve. My chamber is 2 inch 5 feet long. Barrel is 1.5 inch SDR 21 for golf balls. I will use wads for other stuff also. I used a schrader tire valve for the intake. I know i need to paint it and i will also add a gauge soon. Please give constructive criticism and pointers, tips ect ect.

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King_TaTer
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Rabid did you seriously use DWV fittings even after spending so much time in the chat asking questions? I'ts a shame to see them. I thought you were aware of the dangers of DWV. Anyway there is still hope for your launcher. Detach your chamber and cut off the 90° elbow and discard everything attached to it. Then get yourself a pressure rated elbow, reducers and all the necesary fittings to safely attach it to the sprinkler. If your not sure how to identify them, check this out. Good luck.
Materials links:
<a href="http://www.discounthydraulichose.com/">Discount Hydraulic Hose</a>
<a href="http://www.buyfittingswholesale.com/#">Buy fittings wholesale</a>
<a href="http://www.flexpvc.com/">Flex PVC</a>
<a href="http://www.murrayequipment.com">MEI
</a>
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RabidDuck
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I'm sure those said NSF-PW Sch 40 on them but i may be wrong
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FORE!!!!
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maybe u could mount the blowgun directly to the sprinker valve,and get a faster fireing time?

what pressure do u run it at?
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starman
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Keep your pressures relatively low with this thing. You have several DWV connections there. You also have a somewhat larger air tank than is necessary with this setup...I would suggest some 1/2 to 2/3 the size of what you have there. It doesn't hurt anything but all that extra air is just being wasted at the end of each shot.
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RabidDuck
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FORE-Well i haven't fired it that many times but anywhere from 50 - 80 for right now since i don't have a pressure gauge on the cannon and I'm not going for damage at the moment. Instead of mounting the blow gun directly to the valve I'm going to cut down the length of the hose i think.

Starman- would it be easy to fix those things? the DWV fittings and the chamber size? I know what you mean. After i fire it i squeeze the blow gun and more air comes out.
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starman
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RabidDuck wrote:Starman- would it be easy to fix those things? the DWV fittings and the chamber size? I know what you mean. After i fire it i squeeze the blow gun and more air comes out.
Well you could simply saw the tank down and re-cap it. The 90 degree and reducer should be replaced with pressure rated parts. This means basically rebuilding and attaching the tank to the sprinkler valve.
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RabidDuck
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Well i cant really take the cap off but if i need to replace the fittings i would just cut it down on the elbow end. How small do i need the chamber to be? I tried using GGDT but i don't know how to model a sprinkler valve in there. Is the elbow the only non pressure rated part or are there more?
Thanks
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FORE!!!!
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and if u dont manage to change the neccesary parts i would suggest keeping it out of the sun for prolonger periods of time ,this will make the plastic brittle
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King_TaTer
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Read my post Rabid and use the link I provided. You asked the same questions to starman that I had already answered. You could probably get away with cutting the chamber in half and still having enough air. Remember, do not fire it again until you have replaced the DWV fittings.
Materials links:
<a href="http://www.discounthydraulichose.com/">Discount Hydraulic Hose</a>
<a href="http://www.buyfittingswholesale.com/#">Buy fittings wholesale</a>
<a href="http://www.flexpvc.com/">Flex PVC</a>
<a href="http://www.murrayequipment.com">MEI
</a>
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RabidDuck
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Well if some of the pieces are pressure rated why waste them? I was just wondering if the elbow was the only one that wasn't pressure rated.
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FORE!!!!
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u can reuse the cap if u want ,just cut it off flush with the end of the fitting,so ur left with just the cap and the little piece of pipe glued in the cap.

Now be carefull with this, get ur pvc glue and wipe on the inside of the pipe in the fitting a thin coat of glue, get a lighter and ignite the the coat of glue,so its on fire ,make sure ur carefull with the glue and dont burn the cap to much,the purpose of this is to sofen the plastic pipe enuff so it becomes maluble/soft,dont wait till it turns black!! u can also use a hacksaw blade and cut threw the inside of the pipe and stop before u reach the fitting to help with removal

Now that ur end cap has been extinguished and is still hot/warm get a screwdriver and hammer it between the pipe and the fitting untill u reach the the inside end of the cap and them lever it out,once uve got it started u shouldnt have any problems,and if u dont understand what im trying to say do non attempt it, and the quicker u do it the easier it will be cause it needs to be maluble/hot/warm

THIS METHOD can be used on most dwv fittings,atho it may be a little hard to do if using pressure fittings
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RabidDuck
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Well if i need to get the fittings off cant i just cut the chamber where it connects to the elbow? I don't need to take the end cap off of the chamber do i? I'm not sure if were talking about the same thing here.
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MrCrowley
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You guys do realise you can get pressure rated fittings that look like DWV, right? RapidDuck, check all your fittings for a pressure rating or NSF-PW, if some don't have them, then they're not rated.

Nice cannon otherwise, but like starman said, overkill on the chamber.
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RabidDuck
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Okay i did check the elbow and i couldn't find anything on it so i must of screwed up on that. It seems if i cut the chamber in half the gun would be so offset. A long barrel and short chamber i don't know? And does it make sense to cut it off by the elbow instead of by the end cap? thanks for all the help
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