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Cannon Design Help

Posted: Thu Aug 02, 2012 9:08 am
by doomburger
Hey guys! I am designing an aluminum marshmellow spud gun, and I want to make sure my design works before I buy all the things from McMaster.com...
So does this design work? Thanks!
(Don't judge my horrible handwriting/drawing skills :P)

Image

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Quick-Exhaust Air Valve 1/2" Inlet, 1/2" Cylinder/Outlet, 3/4" Exhaust

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Low-Pressure Aluminum Threaded Pipe Fitting 1/2 Pipe Size, Coupling

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Standard-Wall Aluminum Pipe 1/2 Pipe Size X 18" Length, Threaded

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Low-Pressure Aluminum Threaded Pipe Fitting 1/2 Pipe Size, Tee

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(2x) Standard-Wall Aluminum Threaded Pipe Nipple 1/2 Pipe Size X 1-1/2" Length

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Low-Pressure Aluminum Threaded Pipe Fitting 1/2 Male X 1/8 Fem Pipe Size, Hex Reducing Bushing

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(2x) Standard-Wall Aluminum Threaded Pipe Nipple 1/4 Pipe Size X 1-1/2" Length

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Shock-Resistant Gauge Plastic Case, 1-1/2" Dial, 1/8 NPT Ctr Back, 160 PSI

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Low-Pressure Aluminum Threaded Pipe Fitting 1 X 1/2 Pipe Size, Female Reducing Coupling

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Low-Pressure Aluminum Threaded Pipe Fitting 1 Pipe Size, Cap

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High Volume Lever-Handle Blowgun 150 Max PSI, 1/4" NPT Female Air Inlet

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Standard-Wall Aluminum Threaded Pipe Nipple 1 Pipe Size X 8" Length

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Brass Air Fill Valve Straight, 1/4 NPT, 1-3/8" Overall Length

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Low-Pressure Aluminum Threaded Pipe Fitting 3/4 Male X 1/4 Fem Pipe Size, Hex Reducing Bushing

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Low-Pressure Aluminum Threaded Pipe Fitting 1/4 Pipe Size, Tee

Posted: Thu Aug 02, 2012 9:27 am
by Zeus
Chuck an elbow on the blowgun, and you'll be right. I recommend an M/F save on the 1/4" hex nipple.

And replace the coupling on the end with a 1/2" to 1" bell coupling, gives you the option for a suppressor.

Posted: Thu Aug 02, 2012 9:34 am
by doomburger
Thanks, great ideas :P
I'll post a build and damage thread after I finish the gun.

Posted: Thu Aug 02, 2012 12:21 pm
by dewey-1
Here is a 3/4" QEV with 1.5 x 12 chamber.
Total price on this will be less than your preliminary design.

Much more versatile launcher if using 3/4" QEV.

Edit: Added Tire Inflator pilot version.

Posted: Thu Aug 02, 2012 3:01 pm
by mattyzip77
Badass sketches dewey as usual!!!!

Posted: Thu Aug 02, 2012 5:08 pm
by doomburger
You should have posted earlier! Could have saved me a couple bucks :P
Ah well, at least I can say that this was my own design :)
Thanks for the reply!

Posted: Thu Aug 02, 2012 6:14 pm
by dewey-1
doomburger wrote:You should have posted earlier! Could have saved me a couple bucks :P
Ah well, at least I can say that this was my own design :)
Thanks for the reply!
What do you expect in 3 hours time? :D

I am willing to say it probably took longer for you to make your sketch than it took me to do my version. :)

Posted: Thu Aug 02, 2012 9:23 pm
by mattyzip77
Maybe I will make this dewey. Be ashame to see such a good drawing go to waste,,, :idea:

Posted: Thu Aug 02, 2012 9:47 pm
by jackssmirkingrevenge
dewey-1 wrote:I am willing to say it probably took longer for you to make your sketch than it took me to do my version. :)
I believe that :) looks great as always.

I would mod it slightly though, to make it more efficient. Pressure gauge either removed completely (single shot and you should have a gauge on the pump anyway) or relocated to the main chamber, tee at the pilot end removed and schrader attached to the base of the blowgun. You would need to remove the schrader stem, and keep the blowgun trigger pressed while filling.