I am thinking of how I could utilize a spark plug to make a good ignition source for my spud gun. Problem is, I can't figure out where the negative and postitive parts of it are. Can someone post a diagram?
A spark plug really doesn't have a positive or negative terminal--it will fire with either polarity. The 2 terminals are the metal "tip" at the end of the porcelain insulator (where the wire from the distributor connects), and the metal plug body itself, which connects by being screwed into the grounded cylinder head. You need a very high voltage to fire a spark plug. Around 10,000 volts as a minimum. A piezo igniter frrom a gas grill will work, as will an oil burner ignition transformer. Another obvious choice is an automobile ignition coil, but you will need some kind of electronic driver for it to replace the ignition module in the car.
grill ignitor works the best put the screws in both sides of the pipe about 1/2 inch apart tip to tip and then connect the wires to the screws
The screws through the pipe wall have a tendency to misfire when crud builds up on the inside of the combustion chamber, shorting out the spark gap. A spark plug seems more resistant to this kind of fouling, and looks a heck of a lot more professional, too.
Go to the autozone near you, buy a spark plug wire, and another high voltage wire, drill a hole just big enough for the spark plug in the cap, wire, then put the spark plug in the cap in this order, put one washer on the spark plug, then wrap the high voltage wire around the spark plug, insert it into the cap, then another washer, then a nut. Then put the spark plug wire on the end of the plug, and run both lines to teh terminal on the grill ignitor. I did this myself, so it works.
the first time my house got raided by police they found my potatoe cannons and charged me with firearm offences.i dont know about were you guys are from but dont get caught with one in australia.
Potato cannons are specifically exempted from federal firearms laws here in the USA: http://members.tripod.com/j-shortreed/batf.htm However, individual states or towns may have laws against them, so check with local police, or at least use common sense.
LOL, how many times does your house get raided? Why? I'm building a rubber-band gun with 100lbs tension that shoots metal bolts.
Next time you guy a disposable camera with flash, take it apart and keep the flash attachment. That'll do it. And it's more compact than the spark plug idea.
To get a good spark youll have to hook the sparkplug to a coil and a lantern flashlight battery with a pushbutton switch between the battery and coil......Just my thinking
http://www.newegg.com/Product/Produ...oogleMKP&cm_mmc=KNC-GoogleMKP-_-pla-_-NA-_-NA End thread Electric spark = fail Flint spark = boooooom! I've built a few potato guns in my day, Coleman lantern igniter is the best way hands down.
Actually the legality of them is up for debate here in South Australia, at least...a District Court judge recently heald they were not firearms....
