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Building a spudgun designed to run on unregulated CO2

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Originally posted by: Colt45
I vote for PVC pipe + ether
Click to expand...

I wouldn't take the design of one of these too lightly. It is just a pipe bomb with one weak end.

If you use something that expands quicker than it can leave the tube for propellant, it's going to explode.
 
Originally posted by: Eli
Originally posted by: Colt45
I vote for PVC pipe + ether
Click to expand...

I wouldn't take the design of one of these too lightly. It is just a pipe bomb with one weak end.

If you use something that expands quicker than it can leave the tube for propellant, it's going to explode.
Click to expand...
As for the ratio...
 
Ok, here's what I have in mind.
Dual 6" 8-10 foot long air chambers, stacked on top of each other.
Stacked onto that is a 2.5 or 3" barrel, with 2-4 solenoid valves feeding it which are connected to a dual pistol-grip system. This will allow for a 4:1 to 5:1 ratio for even the largest projectiles. Muzzle brake on the end for reduced recoil, and a 2" foam shoulder pad. I'm guessing it'll be 8-10 feet long. Will be charged by an air compressor. The 6" tubes will have an 8" tube filled with sand surrounding it and the barrels will each have a slightly larger tube filled with sand. This is for more durability and safety.
This will own 😀
 
Oh and I forgot, the 3 main components (dual air tanks, barrel) will have PVC unions for easy dissassembly. Can these things handle pressure?
 
For the money, work, and personal hazards wouldn't it be better to just buy a high power rifle or step into pumpkins or something, potatos are limited fun.
 
Sorry, but the PVC unions won't hold, so don't even think about it. I have contemplated the same idea as you, but decided it would cost me to much, and I really don't have the equipment to do it either.

I built this one for a physics project this year, really wish I had used a 3inch barrel, instead of the 2inch as the ratios would have been much better. It is a piston type design, the brass valve is on the backend of the cannon. I believe that it was rated to 1000psi, but won't make any guarentees. The 6inch pvc pressure chamber is only rated to 180 psi, and I have not put more then a 100psi or so in it, and I still had potatoes vaporizing as they left the barrel. Golf balls are fun, tennis balls are fun to, but it just doesn't get the range I expected it too. I believe that it is do to the ratio, if I remember correctly it is something like 23:1, not too good.
My Cannon

Also, some very helpful/knowledgeable people at this yahoo group: http://groups.yahoo.com/group/spudguns/
Check out some of the software for doing calculations of velocities and ratios, it is under the files section.
 
Originally posted by: Soybomb
For the money, work, and personal hazards wouldn't it be better to just buy a high power rifle or step into pumpkins or something, potatos are limited fun.
Click to expand...
Spudgun is a misleading name. The 2.5" barrel fires tennis barrels, and I believe we'll need a 3" for popcans.
 
Originally posted by: TonyG
Sorry, but the PVC unions won't hold, so don't even think about it. I have contemplated the same idea as you, but decided it would cost me to much, and I really don't have the equipment to do it either.

I built this one for a physics project this year, really wish I had used a 3inch barrel, instead of the 2inch as the ratios would have been much better. It is a piston type design, the brass valve is on the backend of the cannon. I believe that it was rated to 1000psi, but won't make any guarentees. The 6inch pvc pressure chamber is only rated to 180 psi, and I have not put more then a 100psi or so in it, and I still had potatoes vaporizing as they left the barrel. Golf balls are fun, tennis balls are fun to, but it just doesn't get the range I expected it too. I believe that it is do to the ratio, if I remember correctly it is something like 23:1, not too good.
My Cannon

Also, some very helpful/knowledgeable people at this yahoo group: http://groups.yahoo.com/group/spudguns/
Check out some of the software for doing calculations of velocities and ratios, it is under the files section.
Click to expand...
Thanks for the info. I'm no n00b to spudguns, but I found that anything over 4:1 is kind of beginning to waste air.
 
Originally posted by: TonyG
Sorry, but the PVC unions won't hold, so don't even think about it. I have contemplated the same idea as you, but decided it would cost me to much, and I really don't have the equipment to do it either.

I built this one for a physics project this year, really wish I had used a 3inch barrel, instead of the 2inch as the ratios would have been much better. It is a piston type design, the brass valve is on the backend of the cannon. I believe that it was rated to 1000psi, but won't make any guarentees. The 6inch pvc pressure chamber is only rated to 180 psi, and I have not put more then a 100psi or so in it, and I still had potatoes vaporizing as they left the barrel. Golf balls are fun, tennis balls are fun to, but it just doesn't get the range I expected it too. I believe that it is do to the ratio, if I remember correctly it is something like 23:1, not too good.
My Cannon

Also, some very helpful/knowledgeable people at this yahoo group: http://groups.yahoo.com/group/spudguns/
Check out some of the software for doing calculations of velocities and ratios, it is under the files section.
Click to expand...
What range did you expect, out of curiousity? I'd assume a good 400 meters minimum with a piston valve design gun of that size.
 
With golf balls I was only getting around 600ft at 90-100psi, much less then it should be. I did have a short barrel, which may have been a big portion of the problem with the golf balls, it was just a length of pvc that a golfball would fit it relatively well and it was slid down my main barrel and liberal duct tape used around the end to make sure it didn't leak.

The xinventions.com site is where I got my idea from, I just upscaled the gun, and really upscaled the cost, as 6inch couplers/reducers arn't cheap, and I am really kicking my self for not going with a 3inch barrel, still have a nice long section of 6inch pipe left so I could build another, but I really don't have the extra cash to do that with, as it would cost somewhere around $200 or so to build.
 
Originally posted by: Munchies
If your going to go compbustion then well I dont know. If u want to go pnematic. go HERE
Click to expand...
Sigh. I know of that site. I already have a spudgun. My goal is to build an 8-10 foot long shoulder-fired dual air chamber interchangable barrel w/ muzzle brake "spud"gun.
 
Here's a tip for your ammo: Core the potatoes to the correct size - freeze them - before firing, dunk it in warm water for a few seconds.
 
Originally posted by: sward666
Here's a tip for your ammo: Core the potatoes to the correct size - freeze them - before firing, dunk it in warm water for a few seconds.
Click to expand...
😀😀😀😀😀
 
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