Scotty

Uhhh, I built one out of PVC pipe that was over 8 ft long. Started with 6" to 4" to 2" with what I called the potato bowl on the end.

After doing a few launches with lighter fluid, then hair spray and then both mixed, we progressed to a small burner in the base hooked up to a bbq tank . First attempt sent the potato so far we thought it blew apart. Nice flame too. Then BOOM and a car alarm goes off and dogs barking.
We put a bigger potato bowl on the end
opened up the valve on the propane full and let er rip.


The fines were less then I thought they would be and only one of us had to go pay for the damages to the city bus...luckily it was out of service.

Just to give you an idea...the cannon fell down and was now at about a 40 degree angle when the launch took place. The potato bowl, 9 potatos and most of the 2" pipe was gone. Good thing we had ear plugs.
The bus was 17, yes 17 blocks away parked in a turn around. It lost a lot of side glass.

The bang from that launch was so loud that the cops had more calls then anything on record at that time. When they came to the door and the backyard and the garage and the side door and the front lawn...several of them the one cop had one look at us and knew it was us.
I had a dark film of soot all over me. My two buddies looked worse and my orange ear plugs, still in kind of solved their mystery.

Do not ask about the Cans of Raid we used for the next cannon.

Scotty

TIMMY22

nice,

behind our farm, there's no houses for 5 miles or so. we should be alright in that department.

how did you get the potatoes to follow smoothly through a 6" to 4" to 2" reducers or whatever you had?


thats what they call potatoe buckshot uhh, i mean busshot!

JARHEAD

Get a golf ball and take the outer skin (white) off of it and take that to home depot. Get the pipe that fits it the tightest. We used that with our tater gun and that thing would fire that ball like a cannon. We have these silhouttes that are made of real hard cardboard (sorta like the case mre's come in) and it would blow a perfect hole in it. That is really saying something being as think as the targets are. Oh yea, the fuel was i believe aqua net. Looked a little silly in uniform buying aqua net at the exchange!!

BIGBADBOB

We made the cannon out of 5 soup cans taped together with electrical tape the second from last can only had a 1.5in hole in it making the last two cans the combustion chamber. We used methyl hydrate as fuel and shot tennis ***** Most would go at least out of site. Still have it somewhere.

Badfish740

I like this guy's idea, (using oxy-propane/acetylene mix) but there's no way in hell I'd be using ABS pipe. I'd have to go with aluminum at least. I wouldn't want to have to get plastic shrapnel dug out of me-especially since you probably can't see it on an x-ray. Check out the pictures of the gun's handiwork towards the bottom.

Bosshawg600

I bult one out of PVC worked good until we made the new one. 1/4" steel tube and compressed propane and tennis ***** filled with sand or golf *****. The shood a good distance. We hiit the golf course across the lake from me and that is 1200 ft. bank to bank!

BigBlue

I use Aquanet hair spray. It's very cheap and very explosive. I use a 2"x30" PVC barrel with a 4"x12-14" chamber on the end and a BBQ striker to ignite it. I've gone well over 100 yds. before.

farmer dave

My friend has one made out of pvc with a coleman lighter and we used Aquanet at first, but that wasn't good enough. We started using a oxy-propane mix and that woked alot better. We were taking big nuts and wrapping them in paper towel to get the tube to seal up. Now that was impressive. We shot some at a old 70's ford and it was putting holes in the metal. We almost shot one through the windowsheild. We also had one ricochet around and that was enough for us. Ah, the good old days! By the way, don't try shooting nuts at stuff because it isn't safe (but it was alot of fun).

Scotty

the potato bowl was threaded onto the end of the 2" pipe. The taper from 6 to 4 to 2 was to assist in the velocity...at least thats what our theory was and it worked. The entire pipe was the combustion chamber. The first potato bowl was a 3" to 2" threaded adapter on the end of the 2" pipe. We put three screws in through the plastic on an angle into the potato to hold it in place snugly sealing as much as possible around the edge. Thats why we thought the potato dissintegrated. The bigger potato bowl was a plumbing masterpiece that looked like an abs chandelier.

gobucks

We built several of these guns, as well; experimenting with a number of different size barrels to handle different sized objects (from ducted taped flour bags to green apples). The most lethal was probably the green apple one. I was just happy that it was my dad that shot it at the horse trailer and not me. If I would have dented it like that he would have beat me into next week.

I would agree that the hair spray seems to give the best combustion, but does tend to make things sticky. We also put a sharp beveled end on our barrels to slice the excess flesh off of fruits and veggy's to ensure a snug fit. The screw on end cap is a good idea as it allows you to air the gun out if you over do it on the propellant or get it sprayed directly on the igniter. It's also just nice to have convenient access to the igniter if you need to work on it our replace it.

In my experience, I guess exact size doesn't matter all that much, as we got a bang out of every one we built. As the others have said, basically, you need a larger diameter pipe for the combustion chamber connected to a reducer and then a smaller pipe for the barrel.

Actually, if you type "Coleman Sparker" in on Google, you'll get all kinds of plans.

SoTexRattler

This ain't quite a "spud gun" but similar principles were at play... Only the weights and pressures have been modified to entertain the guilty...

A former neighbor's dad owned and operated an oilfield directional drilling co. and they use different "subs" or drillstem segments for special purposes.
One special sub was non-magnetic stainless steel with 3 drilled and tapped holes with stainless steel indexing pins for orienting downhole measurement instruments.
Now, picture this:
Two bored and mischevious teen's...
A 4' long "sub" made of s-steel with walls abt 2-1/2" thick and 3 half inch threaded holes in the sides about the middle of the pipe standing straight up on a concrete slab...
A sand filled Pepsi-Cola can was found to JUST barely fit into the bore of this sub.
An oxy/acetylene torch is lighted and adjusted for the "perfect" flame
One of the 3 indexing setscrews is removed and the torch is "tapped out" on the concrete... Insert torch into threaded hole and wait... and wait...
Remove torch, relight and then wave the torch past the open setscrew hole...
Bang!!! OUt of sight!!!!.................WAY out of sight! WAY WAY outta sight!!!
A that instant, a great revelation dawned on all unprotected participants... What goes Straight up in South Texas winds won't necessarily come exactly straight down... We drop the torch, and head for the protection of a nearby metal building overhang...
***BANG!!!*** a partially sand filled Pepsi can at near terminal velocity hitting a metal building makes MUCH more noise than anyone was expecting...
Good thing "dad" wasn't in there...

COOL!!! Let's do it AGAIN!!!

Man! that oxy/acetylene is some VIOLENT stuff! Sure left an impression on me... Almost literally!


K.

StrokeThis2500

does anybody have any pics of there toy

krock

I once built a spud gun just by using a 2 7/8 x 10' pup jt, 20' x 3000 lb shock hose & a natural gas well with about 7 mpa ( 1000 lbs ) pressure on the annulus. The things a bored rig crew can come up with........... also discovered that gophers ( richardson ground squirles ) fit in the barrel & can fly quite well under these circumstances.

Scotty

I think its good to see I was not the only one doing this. LOL
The look on the cops face when he saw us and the smirks from the others when the City Bus Inspector pulled up in his van was hilarious. They told us they were all bored like us and it WOKE UP THE NIGHT for them. Then the Inspector carries out whats left of the multi potato bowl...hahahahah...that thing was a mess and the windows on a bus are not as expensive as I thought.

Anybody ever use diesel fuel and manure for clearing out the gophers?

mtl0727

weve used diesel and fertilizer or however its spelled for moving tree stumps i was just a by stander i dont know the exact proportions yada yada yada but it was somthing to that nature