Spud Gun

P

PumpBlast

New member
Hope this is the appropriate Forum.

Looking to see if anyone out there has any experience with firing spud guns. I want to take it a bit farther than spray in the hairspray and screw the cap back on. I am exploring propane power and the possiblity of modifying a stun gun to use as an igniter. I'm sure it'll be much more reliable than a BBQ igniter.

Thanks

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Gun control is People Control
 
Well, I know of a couple of "Spud guns" that have been taken well beyond the hairspray level and use LPG from a torch bottle and a bbq grill igniter. The ones I know of are made up of the best PVC pipe made in layers at the breech end.

I don't have the plans as I have no interest in building one, I get to shoot the ones in question, however the unit remains closed, the gas is pumped in via a hose and valve unit and then the spud is rammed home. The things recoil and it sounds like a firearm going off.

I am not accepting any responsability for any acidents or injuries that may occure from people building any thing from PVC pipe and such. The above was published for entertainment purposes only.

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Ne Conjuge Nobiscum
"If there be treachery, let there be jehad!"
 
I made mine with Schedule 80 PVC pipe, which is heavier and resistant to cracking (and more resistant to UV light) than the standard white PVC. I used a 5-foot long 2.5" "barrel" and a 5" "combustion chamber," joined by a funnel connector with PVC cement after cleaning and priming. Then I put a screw-on cap on the end of the 5" (or was it 4"? Whatever is standard sewer clean-out sized pipe...) chamber, with a BBQ igniter installed in the cap.

Use a broomstick to shove the over-sized baker into the barrel down to the cone but not into the chamber, shoot 3 seconds of Final Net hairspray in the chamber, clap on the cap, aim, and click PoomP! I could get 200 yards from a good-sized baker!

I just don't think the pressures are real high, here. Nonetheless, use good materials, keep them out of the sunlight (hurts plastics), and you might consider (as I did) throwing a horse blanket over the gun's combustion chamber and cone during the first few shots.

I don't accept any responsibility for telling my own past experiences with a plastic potato-shooter. I am NOT encouraging others to do likewise. Be advised that these things can cause serious injury to anyone hit by the projectile, and that any over-pressure will possibly result in the gun rupturing, hurting the shooter. Try at your own risk.

[This message has been edited by Long Path (edited February 02, 2000).]
 
I've got one of the standard ones that are supposed to use hair spray, bought it at an actual gunshop. I don't use hair spray though, I get a better bang and range out of WD40. The only problem with that is after about five shots I have to wipe down the igniter or it wont spark. I want to try one with an electronic igniter from a barbecue grill and the aerosol refill for cigarett lighters or mayby even starting fluid but havn't gotten around to it yet. Just be very carefull not to blow your head off.
 
Lachfal,

Look man. Don't go screwing around with lighter refills and starting fluid. That's in a whole different class then wd-40. I've seen pistons and heads blown to pieces on internal combustion engines and they were made of better stuff then pvc or whatever you're probably using. I have some experience in research and development work with various fuels and lubricants and they are very unforgiving. No second chances and they don't care.

Just make sure you do your homework. Anything you mess with in this area can kill you or destroy your useful life. It can make things real ugly if not properly researched.

If you seriously want to mess with this stuff please do it methodically, safely and shield yourself and others from a possible mis calculation. Take cover and don't shoot from the hip.

I for one am not interested in sending out any more cards or flowers.
 
Here's a different kinda spud gun...

When I was doing WWII reenactment, some of the Germans in Fla. and some of GI's here in GA formed mortar crews. They'd start with a set of legs and a site (available from army surplus stores and collectors - perfectly legal) and then got a steel tube of the appropriate diameter. Usually, a reinforcing band was added where the legs wrap around the tube. Then, a steel end cap was welded to the bottom of the tube. A short length of steel rod (about 1/2" diameter) was welded to the bottom of the cap, and a steel ball was welded to the end of the rod for a swivel. The base was shaped (I don't remember the dimensions) and some "feet" welded to it; and the base was heated and "dinged" in the center for a seat for the swivel ball. Then, a piece was cut and bolted in to hold the swivel ball to the base plate, attach the legs, and voila - a black powder mortar, complete with sights and T&E mechanism.

Rounds were made in two parts - a projectile round and a charge round. You need:
1) several soft plastic sample bottles that just fit into the tube (you'll use 2 per shot)
2) cannon fuse
3) some dowel pieces (I think 3/4" by about 3" long was used)
4) A milk jug (cut up for stabilizing fins)
5) Heavy duty stapler
6) Hot glue gun
7) Sand blasting sand or kitty litter
8) something to hold a measured black powder charge in - I've seen them fashioned by shaping a piece of aluminum foil around a dowel, but a small plastic sample bottle works best.
9) some black powder. I think FFF was used for the propellent; I know FFFF was used for the "round" - I don't know the charges used - you'll have to experiment.

To make the charge, the powder was placed in the small container, a fuse was added, and it was sealed with hot glue. Then, a hole was placed in the base of the neck of the charge container (part #1), the container was half filled with sand, the charge was added and the fuse fed through the hole, the charge round was filled with sand, the lid was put on & sealed with hot glue.
The projectile was made similarly, except a short length of dowel (3-4") was added to the lid (stapled, I think) and plastic fins were stapled to the dowel for stability in flight. On the projectile, a short length of fuse was left sticking out (about 1/4" or so) and the majority of the fuse was left coiled on the inside (the length of the fuse is determined by the burn time - you have to burn and time a few pieces).

Then, set up the mortar, light the charge round & drop in the tube lid-up, drop the projectile in on top of it (the charge will also light the projectile).

With practice, it's good out to about 200 yds. And can be pretty darn accurate, if you experiment enough to calibrate the rounds to the sights. I've seen the accuracy myself - I've had them land within 5 ft of me at over 100 yds out.

BTW, the projectile rounds were designed specifically not to hurt anyone - the charges were about like a big firecracker. The safety officer at a reenactment would pick one mortar round or grenade out of your bag at random, and whoever brought it would have to light it and drop it between their feet or set it off on their helmet.

For you propane-powered spud gun people, I've seen rocket igniters and 9-volt batteries used for detonators as well as the old fashioned camera flash bulbs - just cut or carefully break the glass off of the flash bulb.

NOTE: Do NOT put any sort of firing pin in the tube or plate. If you do, you have just manufactured an ATF "Destructive Device". Go Directly to Jail....

More important note: Should you actually be crazy enough to try any of this, I won't be responsible for any damage or harm done to yourself or others!!!
 
These guys make all other potato guns look like pea shooters:

http://www.ittc.ukans.edu/~botanika/warning_label.htm#bfpg

"A mach 1 capable pneumatic potato gun with interchangeable 10', 20' and 40' barrels ranging from 1 to 2 inches in diameter"

This baby is pressurized at around 125psi, a hairspray can gets you about 15-20psi..

Anyway, check it out, there's some great movies of watermelons being blasted at point blank range. :)

..tm
 
Like RugerGuy said, PumpBlast, watch your step & BE SAFE.

I made UPI for blowing up my best friend's living room when in high school. Only six days in the hospital & (almost) good as new.

There's stuff that goes boom & stuff that goes BOOM! I wasn't doing spud guns (much better! ;) but the principle applies.
 
RugerGuy, I'm sure the heads you've seen were the result of fuel being compressed to incredible pressures. We're just talking about a miniscule amount of propane with no compression. Heck it's flammable range is only 2.1% to 9.5%. With a combustion chamber 3"D X 12"L we're dealing very little fuel.

Danger Dave, sounds pretty cool. It's conceivable that something very similar could be done with a spud gun. 1.5" schedule 40 (thicker than 80, I checked) PVC will allow a short piece of .75" PVC with two end caps to be slid down the barrel. Now if some crazy nut were to put Black Powder inside with a hunk of cannon fuze sticking out the end, that'd be dangerous. Of course if some crazy stupid idiot were to be so dumb as to try this, he should test fire with dummy loads filled with sand first. Everything should be glued with PVC glue after using the appropriate primer.

Of course this is totally dangerous and should NEVER be done. I know I never will. :rolleyes:

But seriously, I am looking for SPECIFICS on the propane fuel delivery. Thanks


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Gun control is People Control
 
http://www.goldmann.com/spudgun.html

When you're ready to get serious, check this guy's site out. He sells RIFLED PVC for goodness sake.

Make sure you check out: http://www.goldmann.com/spudgun/sp9004.html
This guy has buitl the ultimate man-portable spud gun, the "SP9004"
A quote from the web site:
"Presenting the SP9004 now in true operating form, optimized over the past several years. Pure oxygen and propane fueled, laser sighted, bolt action, electrically controlled....This is one awesome piece of launching ordinance! Detailed descriptions of each operation area of the launcher with an index will be back shortly.

A brief operational note--The potato slugs have an average mass of only 62 grams, but conservative calculations reveal they possess at least 1500 ft-lbs of energy at the muzzle, which in turn punches quite nice round holes in 1/2" CDX plywood at 50 feet. It is powerful, but is still fun to fire in a safe manner.

If you would like to build this amazing device or just find out more detailed information you are in luck as I have drafted a document that describes everything about the SP9004, in addition to the backpack unit that supplies everything this launcher needs for seamless operation."

This guy knows how to have fun.....
 
I'll have to hunt up the URL on this one--a group of engineering students (some geeks have all the fun) put together the "BFSG9000" which could accelerate a spud past Mach 1 with compressed air.

One of my coworkers and his friends put one (just a garden variety spud gun, NOT a BFSG9000) together to snipe at boaters who refuse to obey the "no wake" rule inside some of this area's waterways.

jth


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Don't give me a "smarter" gun.
Make me a smarter shooter :D
 
Hey Keystone,
Thanks for the cool site. The Goldmann guy has a passion for the spud guy! I don't know about anything using oxygen though! Even at the Fire Dept we get big time anal about smoking and oxygen!
 
I don't suppose substituting french fries for shot in a 12 ga. is in the theme of this thread is it?
 
Pump blast,

It doesn't take as high a preasure as you may think. And the ones I'm referring to weren't all that much pressure. You are correct though, more presssure more boom.

However, that's not the point. The point is, investigate a little. There's plenty of information available about various fuels. Burn rates, volatility, etc.

Overall, the propane is a pretty good choice because it's easy to dial in. Consistancy in product seems fairly good. Also, it only develops about half the BTU's as say...kerosene, if my memory serves me. You can get the valves ,tanks and hoses easy enough. You may want to use an injector type system for really accurate control at the combustion chamber.

I don't care for liquid fuels too much because they can absorb into your clothing, the surrounding area and stay on your skin.

Gases tend to go away easier.

When I tell you to be careful I'm not being a smarta**. It's only because I've seen and experienced some pretty close calls. But it does get your blood pumping a bit.

Kind of like one of my first experiences as a kid when I decided to see what a moped would do on a variable mixed diet of nitro and gasoline. :) But that's another story. :)

Or the time I was in the pit area straddleing a running 900hp alky engine looking down the carb to see if everything seemed o.k. while gunning it. :) Found the problem...accelerator pump adjustment.

You see, I've done my share of really dumb stuff. But it sure was fun. Oh yea, the car one the race.

Have fun and don't blow your self up.

I think there are some good sources for propane conversion kits and parts for internal combustion engines. Some of this stuff should apply. At least in concept. Maybe some good ideas there.Let me know if you want me to dig up the info.
 
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