Update 8/6/08 Damage pics and VIDEOS (yeah!) on page 5

[ImHUGEnJAPAN]

UPDATE: 7/25/08 New pics on page 4 (primer stage)

I took my canon to the lake house last weekend to see how far I could shoot a potato out into the lake from the deck. My dad has been waiting to shoot this thing as well. I was also excited becuase my Dad has a beefy air compressor so I could finally crank the this up to 120 psi (valve is rated at 150 psi).

I didn't have a barrel support on the orignal design and I think I stuffed the potato in too tight, becuase when I shoot it the Barrel broke off at the sprinkler valve. It was a clean break and I didn't get hurt. The potato shot a good 200+ feet. Not bad for a 20" barrel.

Originally I glued the threads on the valve so we bored out the broken pipe and threads on the vavle and glued the barrel back in. I should have added a longer barrel but i'm going to make another cannon very soon, so I just decided to leave this on as is.

I added a barrel support this time around (actually my Dad did it while he was on vacation last week, that was cool) so the barrel is a lot more stable now.

Since the paintjob got messed up fixing the gun and the barrel supports where unpainted. Ive decided to give it a new paintjob. I'll post picks when it's done.




Finished, MORE pictures on PAGE 4

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I give you the CROSSBOW. The barrel is 20" and the air chamber is 60". We will see how this affects the power. This gives me a 3:1 ratio.

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I want more power...need help.

My first test fire was nothing short of, lets see how to put it..........uhhhh PATHETIC I Want more POWER!!! I can't really change the design becuase everything is glued solid. I can however expand the air chamber very easily. Here is my idea for expanding the air chamber. Will this design work or will the performance still be in the toilet? The first design looks goofy it would be in the shape of an "S" . The second option I think would look pretty cool with three air chambers underneath the barrel, I don't know how it would perform though ?

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Ok, here it is! First off the primer job sucks, but I'm painting it sometime this week. I just haven't decided what color. I plan to use this for paintball as a "one shot" grenade launcher or grape shot device. I haven't had a chance to chrono it to see if it will be safe or even have enough power to shoot enough paintballs far enough to be effective. I can always expand the air chamber later for more power. I used a cp-100 rain bird for the valve and it seems to work ok. No damage pics yet.

I live in an apartment complex and cranked it up to about 50 psi last night and it was really LOUD when I let it go among the buildings. I want to crank it up to 90 psi, but I need a better gauge, my wimpy tire gauge only goes to 50 psi so I didn't want to risk over filling it.

The air chamber is 12" long and the Barrel is 20". I hope the wimpy air chamber will be enough. I know it's not a 1:1 ratio, but I tried to make it as compact as possible. It's a little bigger than I like, but this should work great for castle games.

Everything is sch 40 pvc. This site was great for doing research. So many designs to choose from. There are some amazing cannons on here. Enjoy the pictures.

I forgot to add I would like to try and make a safety. (like on a gun, so it doesn't accidentally fire) Anyone have a picture of something that works??? I just thought I could use some hose with a small ball valve between the valve and the blow gun. In theory that should work, yes ????

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[jrrdw]

Whats the bore size? The top pic is real small, hard to see. Looks like fun to shoot. Any chance of a video clip in action? Nice build for a first!
Welcome to Spudfiles.

Edit: Ok pic refreshed to full size, still can't tell bore size though.
If you want more power, a 2:1 chamber to barrel ratio is more ideal. Relocating the valve to just behind the barrel would also help, eliminates dead space in between valve and ammo.

[brother361]

the bore size looks like 2in
looks cool good job paint it maybe

[Fnord]

For a safety just put a 1" pvc ball valve between the barrel and the valve. That way there is no possible way the gun can fire accidentally.

Except for the primer everything is lookin' good. Camo maybe?

[biggsauce]

I like it! No shame in excess primer/cement. At least you can be confident it wont fly apart or leak.

You say you want to use it in the field for pb, what are you filling your chamber with?

[bigbob12345]

Nice job, i see you have done your reasearch.
Contrary to what jrrdw said i think you should make the barrel longer. It would look better and get a tiny bit of a performance increase.

again nice job for a first

[Hubb]

Looks good, even with the primer

As far as a safety, put a small ball valve between the blowgun and sprinkler. Also, have you shot it yet? The reason I ask is because my last sprinkler valve launcher was set up similar and I had problems with the blowgun moving due to recoil. If that is a problem, remove that elbow and turn your valve so that it is up-side down.

[starman]

I forgot to add I would like to try and make a safety. (like on a gun, so it doesn't accidentally fire) Anyone have a picture of something that works??? I just thought I could use some hose with a small ball valve between the valve and the blow gun. In theory that should work, yes ????

I wouldn't put a ball valve safety in front of the blow gun....opening the ball valve could still cause a slight blip of uneven pressure to show up at the diaphram, thus firing the gun or partial fire anyway.

A real safety would be a ball valve between the airtank and the sprinkler.
Also like jrrdw said, move the sprinkler directly behind the barrel, less dead space.

Looks like 2" tank and barrel. BTW, If you are in the US, you can use Oatey Cleaner to prime your PVC joints. No need to fool with the purple stuff to build spudders. http://www.spudfiles.com/forums/pvc-pri ... 13840.html

Welcome to Spudfiles?

[judgment_arms]

Nice cannon.
Look up Goathunter’s “Goat’s Gun”, the breach on that would be easy enough to add on this one, and would double effectiveness.

I agree with _Fnord on the safety, no way it’ll fire with the safety on then… just make sure your sprinkler valve seals quickly, other wise when you open the ball valve it will just fart out all or part of the air.

As for paint, a simple coat of Krilon Fusion in ultra-flat OD would be nice.

Welcome to the forums!

[ImHUGEnJAPAN]

Thanks for the comments and the ideas. The bore size of the Barrel is 2". I do plan on painting it, just haven't decided what color. I'm leaning towards tiger stripe. Everything is glued solid so moving the valve is not really an option for me. I will keep that in mind for the next gun.

The trigger does have some play, I left the solenoid in to stop the trigger from moving. Perhaps I will zip tie the solenoid to the trigger to keep it in place. I don't know if I like that idea though.

I just plan to fill the chamber with air using a bike pump. This was designed as a one shot device. I can add a co2 regulator later, but I just didn't want to spend the money for one. Besides this was my first attempt and I now understand the basic construction. Now I can improve my design for the next gun.

[SpudFarm]

try to make a piston valve next time

really nice first gun!

[ImHUGEnJAPAN]

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This is my simple idea for a safety device. I could just insert a small clip to keep the trigger from pushing down. Sometimes hand soap pumps have little clips on them to keep you from pushing the pump down. Something to that effect. I think this could work. I just need to find a small enough clip to fit.

[judgment_arms]

Sounds like a plan. If you put a tab though the trigger lever you could slide it on and off easy.

You know, come to think of it, I believe I have seen blowguns with safeties… I think it was at a harbor freight, or a northern tool and equipment…

[jrrdw]

Look at the safty built into this air tool. You could build one like it. They work well, I wanna unhook all mine because they work well, if you have to work fast, what a pain in the ass!

[STHORNE]

Sounds like a plan. If you put a tab though the trigger lever you could slide it on and off easy.

You know, come to think of it, I believe I have seen blowguns with safeties… I think it was at a harbor freight, or a northern tool and equipment…

Actually, i do recall seeing something like that in the latest Northern tool catalog. they were around 11-15 bucks.