These things are a lot of fun, I shoot taters, tennis balls, golf balls etc..I use ether for propellant....if you have never made one, you should
2 foot section of 4 inch PVC pipe
4 foot section of 2 inch PVC pipe
4 inch to 2 inch PVC pipe reducer
4 inch sewer cleanout plug
Electric barbeque starter
Screws, epoxy, hair spray and a big bag of potatoes that are larger than 2 inches in diameter
Sharpen the end of the two inch diameter pipe, it should cleanly core a potato when inserted. At about 4 inches from the other end, insert 3 or 4 screws in a way that will prevent the potato from falling into the combustion chamber.
Use the epoxy and glue the pipes to the reducer, and the sewer pipe end on the back of the gun.
Drill two holes across from one another, and install the electric barbeque lighter, following the directions that come with your igniter.
Note: If possible try to buy the two-wire push button switch, rather than a single wire model, as it is easier to install. Use a nail or bolt to serve as the ground contact. Test the distance before you glue things into place, to make sure you consistently get a good spark.
Insert a potato into the gun barrel. Using a broom handle or similar item, push the potato down down the barrel to the screws at the bottom.
Unscrew the plug at the back, and give the chamber a short burst of hair spray.
Note: The amount of fuel is very critical! Too much and it will not ignite, and not enough and you will get a poor shot.
Aim carefully and ignite your potato gun.
Once you are satisfied with the potato gun operation, try some target shooting, long distance records, and maybe bazooka-style shoulder launches.
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Last edited by Rommelvon; 04-29-2007 at 11:33 AM..
Rommelvin, This takes me back to my childhood! it was alot of fun shootin tennis balls with something similar made of the steel pop cans and duck tape. We also used a piece of steel water pipe that a 12ga. shot shell (empty!) would just fit in. The brass base is the heavy part of the shell and became the front of the projectile. Capped off the back end with a pipe cap with a hole drilled in it for a fire cracker fuse. Simply put he fuse through hole screw on the cap , insert 12ga. hull in the other end and let her rip! amazing how far it would go, 300 ft+.
Spud guns are loads of fun, I have two of them. The first one I built when I was in high school, it was just a small one and had an inefficient combustion chamber. About ten years ago I improved on that design and built a much bigger one. This one uses a 4" chamber about two feet long with a 1 1/2" barrel thats about five feet long. It can easily fire taters or other objects up to 100 yards or more. I stopped using hair spray years ago because of the sticky mess. Now I just use propane from a disposable cylinder. Given the right fuel to air ratio this thing can really pound them out there. Make sure you use schedule 80 PVC pipe, its much stronger and can withstand higher pressures. Also don't be tempted to add oxygen to the mix since this can lead to explosion and serious injury.
There are entire websites devoted to spud gun techonolgy. Some guys use electric fans inside the chamber to help promote better combustion and fuel metering valves to inject the right mixture of propane. There are even pneumatic ones that use compressed air with electric solenoids which dump the air pressure to fire the gun.
I used to fart arround with spud cannons. Mine were pretty elaborate. I used a high pressure coupler so i could take the barrel off and stab the spud into a slightly ground out chamber "in the barrel" thus eliminating precious potato juice that is lost ramming the thing all the way down the barrel....
My problem was that hairspray and either were just to darn boring. I started using propane...which was good. Only problem was that follow up reloadings seems to lack zing even if i allowed the chamber to air out and reoxygenate....so i started using pure oxygen before the propane charge...which worked fine if i used a dosing system for the propane after the oxygen.... I blew up alot of cannons to say the least. Never got hurt with the oxygen propane combo.....until i tried BUTANE!!!!! The chamber and even the 2/3 back portion of the barrel were shattered into thumb size pieces. I got cut up...burnt...knocked down and it took 2 hours before i could hear anything and 2 weeks for complete hearing recovery.
Thats when i gave it up.
Where O where are you tonight? Why have you gone and left me alone? I searched to world over and a thought i found true love... You met another and PTThhh you were gone....
What's most fun about this is the possibility of smaller calibers. Radish Revolver? Peanut Pusher? Endless are the possibilities for American Shooters! Spud Guns? Step up to Eggplant Erasors, Cantalope Crushers, or Water Melon Mashers! A twelve to sixteen foot barrel can lob a water melon 12 miles. Yes, you read it here.
Made the similar a couple years back, only with an air compressor, had three barrels. Used it to make a 20ft tall paper mache volcano that would "erupt" candy for our church kids. It was quite fun shooting gummy bears and such 50 feet into the air pegging little kids on the head. hehe.
Also made a 3 person slingshot so my class could sneak up on other classes outside and launch some "indirect fire" in the form of waterballoons at them.
Man..i was was popular with the Sunday School kids but always in trouble with the pastor.