Sparks280zt Posted June 4, 2007 Share Posted June 4, 2007 cucumbers, apples, etc! A 2.5 inch barrel will allow a 20oz. bottle and a 2.5 inch will also allow you to put in a spray paint can cap in the barrel. Then you can put whatever in the cap, (dog crap, water, golf balls, etc) and once the cap clears the barrel it will catch air and stop while whatever you put in it keeps going. Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted June 5, 2007 Share Posted June 5, 2007 you can use the golf ball.. just have to wrap in tape like i said lol... i've been using all kind of stuff... just have to wrap it in tape to get a snug fit. the bbq lighter sucks... but i've got 2 pieces of 10 gauge wire snug inside instead of 2 screws to make it arc... the 2 wires work ALOT better.. and are stiff enough that they wont move around out of shape when the blast occurs.. lol... a golf ball w/tape will put a hole in 1/2 plywood w/my gun... biggest problem i have is spraying the hair spray i guess sometimes i spray it too close to the chamber and it gets wet... have to vent it out then leave my back cap off.. let it shoot fire out the back.. and start back over fueling.. lol ***EDIT*** i want something HARD... not fruit lol.. i want a punishing hit!!! Quote Link to comment Share on other sites More sharing options...
280zx_sliding Posted June 5, 2007 Share Posted June 5, 2007 I personally never made a potato gun but what about an extra spark plug with a car battery. i know i have like 3 batteries and about 1 million plugs in my drive way... so if you build a stationary gun that you can disassemble in a short time you coulbe be really accurate with tons of spark. just use metal with threads that can fit a spark plug and ground that out. then hook up some wires to the battery with a plug wire on the plug. touch the two together and let her rip. Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted June 6, 2007 Share Posted June 6, 2007 that could possibly work.. i got my prob fixed tho i think... mainly it just dont like to fire when you over fuel... i guess it gets too wet and weakens the arc... lol i almost lit my hair on fire by taking the back off to see if it was getting spark... bad idea... good reflexes. lol. Quote Link to comment Share on other sites More sharing options...
Challenger Posted November 12, 2007 Author Share Posted November 12, 2007 Well I never got around to showing what I ending up doing so heres a couple pictures. I shortened the barrel and it works alot better shoots about 150+ yds which is far enough to hit the school roof. I drilled to holes in the chamber and mounted the two electrodes in the hole. I had alot of trouble getting the spark to be inside the chamber but with some strategically placed pvc and epoxy it all works great. First pic is inside looking at the 2 electrodes, second is outside with the taser. I just shot one off and you here the first explosion when it shoots and then 3 or 4 sec later you here a bang when it hits the metal roof. Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 16, 2008 Author Share Posted January 16, 2008 Well heres an update, I havent changed anything on my current gun but will be making a new one. A bunch of people I know wil be having a potato gun contest and most of the people are kinda stupid but their are some chemists and machinists(so metal piping=aceytlene/oxygen) so those are the guys Im needing to beat. I picked up an 11 inch sewer pipe at our school today (being remodeled) and I have some 1.5 inch abs black piping Ill probably use for the barrel. So far everything has been free so now Im needing to find all the caps, reductors, etc. Im hoping to have a 300-350 yd gun. Im trying to figure out if having the ignitor in the back is better then having it in suspended in the center of the pipe in the middle. Heres what Ive got. Any opinions or ideas... Quote Link to comment Share on other sites More sharing options...
Sparks280zt Posted January 16, 2008 Share Posted January 16, 2008 If you use cast iron and just air pressure, no combustion needed, you can go 500+ yards all day easily. Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 17, 2008 Author Share Posted January 17, 2008 Yeah but I dont have a compressor so I ruled that out along time ago. Also the good thing about a combustion one is its portable. I can break mine down to about 2 ft long and fit the taser, potatos and fuel all in the chamber. Its alot easier to carry around. Quote Link to comment Share on other sites More sharing options...
Sparks280zt Posted January 17, 2008 Share Posted January 17, 2008 You can use a standard bicycle pump. Size isn't everything, there is actually a ratio of barrel volume to chamber volume that yields the greatest result. Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 17, 2008 Author Share Posted January 17, 2008 Yeah I was experimenting with the barrel length. The length Im using now seemed to be the best. I figure you want the barrel to end where the force exerted by the blast peaks. Any less and you dont have the full potential, and any more and the potato is starting to slow down. Im guessing that the ratio would be close to ~1/2 of the chamber volume, but I have no way to figure it out. You have to consider the amount of fuel/air, volume, where the ignitor is etc. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 17, 2008 Share Posted January 17, 2008 If you pressurize the chamber AND add spark/fuel..................you would have a turbo spud gun! I'd just say be very careful with the acytelene...LOL It's not that great if you don't have a perfect fuel/oxygen mix. What about a diesel fuel injector right in the combustion chamber to inject the fuel? Quote Link to comment Share on other sites More sharing options...
woldson Posted January 17, 2008 Share Posted January 17, 2008 Iam thinking megasquirt, wasted spark and injectors! Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted January 17, 2008 Share Posted January 17, 2008 If you use cast iron and just air pressure, no combustion needed, you can go 500+ yards all day easily. I built one using this method. I never did get my sprinkler valve to work electrically though. I had to go back and get one of the diaphragm type I could modify to work off a lever. I'll take a pic of it if I ever get back out to the ranch. Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 18, 2008 Author Share Posted January 18, 2008 Well my original potatoe gun was using Nitro methane and compressed air. So in a sence it was a supercharged/turbocharged nitro potato gun. I had a hard time keeping the potato together. Ive been looking around town for a reducer from the 10 inch down to a 5 inch but have been unsuccessful. I still have a few other places so Im hoping Ill find something. Woldson any ideas where to look? Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 25, 2008 Author Share Posted January 25, 2008 Well I ended up getting a free air compressor today. Im considering going the pneumatic route but not sure. If I do I have to options. I have the piece of Pvc pictured above and I also have a large piece of 4in inside dimension steel pipeing with 1/2 walls. If I go the air route which should I use? The good thing about the metal is Id be able to sell the rest of the metal I dont use which is around 4 ft or possibly trade for the barrel/reducers. Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted January 25, 2008 Share Posted January 25, 2008 As a ex plumber me and ex coworkers have made MANY a spud gun. pneumatic wins every time. You can use pvc but you have to be care full which kind you use. I wouldn't go to home depot and get cheap white schedule 20/40 pvc and use it, very dangerous. They make pvc pipe for residential sprinkler systems, its orange, is crazy strong, better resists heat and is not as bridle as regular pvc. Schedule 40 of this type will get you up to 400psi safely and I can't see anyone even using that much, I find after about 300psi anything organic you use as ammo will blow to pieces. I used to use the non name brand vortex footballs(dollar store), both the small and large ones. At 200+ psi those things are GONE. They won't kill someone either. I would just go to to a plumbing supply that carries sprinkler pvc and get a half length of the 2 sizes you choose(barrel and res), a reducer, glue(sprinkler pvc doesn't use a cleaner) and electric diaphragm valve. Then pick up teflon tape and a schrader valve from any hardware store and your done. For filling they make tiny portable compressors you can plug into your car lighter, thats what I used. If your into a covert bit a bike pump works fine too but it get tiresome pretty damn fast and expect a good 15+min to pump that much. Also for the covert is to use a threaded coupling right after the reducer so you can break it down for travel. Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted January 25, 2008 Share Posted January 25, 2008 P.S. people always argue over abs vs pvc. If your curious abs > white pvc at = schedule but orange pvc > abs in any schedule. Quote Link to comment Share on other sites More sharing options...
Challenger Posted January 25, 2008 Author Share Posted January 25, 2008 Yeah Ive always used the black abs schedule 80 pipe. Dont want to mess with much less. Ive also included the threaded barrel so I can break it down and have quicker reloads. (no need for a ram rod) Do you know what the green sewer pipe (c900?) I have is rated for? (psi) Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted January 25, 2008 Share Posted January 25, 2008 c900 is blue, I forget what the green is, its been so long. c900 goes by SDR ratings, so it depends what you buy. It ranges from 100-250psi. I know the green def doesn't range passed 200psi (if that) because its primarily used for gravity drainage. Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted January 25, 2008 Share Posted January 25, 2008 I'm telling you though that orange sprinkler pvc is where its at. Scedule 120 maxes out at like 1000psi all the way up to 18", fitting to match lol. You have to check fitting ratings too on w/e you choose as the larger in diameter you go the sharper the rating falls. Reg white pvc for example at 3/4 inch is like 650psi but at 12" its about 150psi. Also your method of joining, the primer/glue method is 2nd weakest to I believe restrained? Like is used on the green pipe(basically sliding a male end into a female end that contains a gasket.). Quote Link to comment Share on other sites More sharing options...
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