Spark Plugs

Bowman · Tue May 01, 2012 4:25 pm

Well, I'm still in the design process of making a Semi-Automatic combustion launcher. The original design used a piezoelectric BBQ ignition system which was fairly simple. But I've come to discover in recent ignition testing that the igniter has some inconsistencies with sparking. I think the problem is that it's not creating a hot enough spark or just a very weak spark. So my first alternative was spark plugs. I've researched in how you hook them up. From my understanding a basic circuit would go like this: battery - switch - capacitor - ignition coil - spark plug. This seems a little more complicated than it really needs to be so maybe you guys could give me some information on how to hook up a spark plug in a spud gun.

jsefcik · Tue May 01, 2012 4:53 pm

personally i just recently hooked up a stungun to my biggest combustion cannon,

i got one online for 20 bucks, i crack the case open and cut off the old prongs on the stungun and solderd wires and ring terminals and installed threaded rod in the chamber and followed a doulbe spark set up and works great!!!

id say go with a cheap stungun!!

Bowman · Tue May 01, 2012 5:03 pm

I'm not too good with modifying things especially electrical things. I can see my self sitting in my workshop working on a stun gun and all of a sudden there is around 50,000 volts going through my body. I'm good with electronics. But I do understand basic principles of a circuit. So, any idea on how to hook up a spark plug? And if you're concerned with cost then wait 'till you hear this. A spark plug is around $10 tops, basic electrical switch is around 5-10 bucks, a capacitor is around 2 dollars, and from my understanding all an ignition coil is is a iron base with copper wire wrapped around it. So, total is around 20-25 bucks. I'd say cost is not an issue. Sorry, don't mean to sound like a smart ass but I told ya so

Fnord · Tue May 01, 2012 5:28 pm

Go to walmart and look for a battery powered grill igniter. They're super easy to set up, and probably around the same price as a stungun.

Oh, and most common electrical components are free on trash day

Spark plugs are only necessary for small guns running at very high pressures (hybrids). You'll be fine just using a normal spark gap with screws/bent wire. Spark plugs don't actually have much effect on how hot the spark is.

Bowman · Tue May 01, 2012 5:29 pm

Seriously? Come on I just want to know how to hook up
a spark plug in a spud gun. The chamber is going to be aluminum that is why I don't want to use a BBQ igniter because the screws that it would connect to would be connected to the chamber so the chamber itself would short out the circuit. Don't mean to sound rude

Fnord · Tue May 01, 2012 5:35 pm

Well, you'll need to buy a tap for cutting plug threads if your chamber is metal. You can usually find them on ebay.

Bowman · Tue May 01, 2012 6:37 pm

Haha....thank you. by the way nice philosphoraptor avatar.

mark.f · Tue May 01, 2012 7:55 pm

You can use a grill igniter with a spark plug, probably easier than using an ignition coil.

Zeus · Tue May 01, 2012 8:20 pm

There is a motorbike spark plug that fits 1/8NPT fittings, I think it's CR(something)10K. That'd be easier to install.

And you won't be able to make an ignition coil like that, not without oil submersion or vacuum potting in resin.

Ignore the 6 volt battery, you'll want a 12v battery.

Bowman · Tue May 01, 2012 9:03 pm

Ok, I have a question. Could I have a circuit that starts with a 12v battery then goes to a capacitor to a switch to a spark plug? And the only skepticism I have about hooking a grill igniter to a spark plug is that I'd just be getting the same amount of spark which wouldn't really help and there's still the problem of it sometimes not sparking.

kydavies · Tue May 01, 2012 9:19 pm

Could have sworn I hit the edit button.....

kydavies · Tue May 01, 2012 9:22 pm

kydavies wrote:
Fnord wrote:
Oh, and most common electrical components are free on trash day

My favorite day of the week 8) Also we have free dump day (like Christmas for dumpster divers) where most people takes there stuff to the dump, others like me take stuff (the good stuff) :oops

Anyways, i dont know much about cars of spark plugs but I see no reason why it wouldn't work given that you can get a large enough cap

Crna Legija · Wed May 02, 2012 1:05 am

Zeus wrote:There is a motorbike spark plug that fits 1/8NPT fittings, I think it's CR(something)10K. That'd be easier to install.

cr10ek, they are a bit loose but i think they will be fine for 10x

jimmy101 · Wed May 02, 2012 4:21 pm

Bowman wrote:Ok, I have a question. Could I have a circuit that starts with a 12v battery then goes to a capacitor to a switch to a spark plug? And the only skepticism I have about hooking a grill igniter to a spark plug is that I'd just be getting the same amount of spark which wouldn't really help and there's still the problem of it sometimes not sparking.

Nope, won't work. Even with the Cap it is still a 12 volt circuit.

A battery operated grill igniter will work. Not "sort of work", it will work and will be 100% reliable if done correctly.

A stun gun is trivially simple and only a couple bucks more expensive than a battery operated grill igniter. Afraid of getting shocked? Take the frickin battery out before you take it apart.

jsefcik · Wed May 02, 2012 4:40 pm

jimmy101 wrote:
Bowman wrote:Ok, I have a question. Could I have a circuit that starts with a 12v battery then goes to a capacitor to a switch to a spark plug? And the only skepticism I have about hooking a grill igniter to a spark plug is that I'd just be getting the same amount of spark which wouldn't really help and there's still the problem of it sometimes not sparking.
Nope, won't work. Even with the Cap it is still a 12 volt circuit.

A battery operated grill igniter will work. Not "sort of work", it will work and will be 100% reliable if done correctly.

A stun gun is trivially simple and only a couple bucks more expensive than a battery operated grill igniter. Afraid of getting shocked? Take the frickin battery out before you take it apart.

yes a electric grill ignitor is a little less expensive, but its doesnt give you 100,000 volts or more like a stungun

the wires are easy to hook up

an electric grill ignitor is probally a lil more then 20 bucks, plus you need batteries,

id still say go with the stungun

the stunguns will zap you if your not paying attention, and there is very little amperage, not enough to kill you, if the amperage was high i dont think the would sell them if everytime someone got zapped they would die

Spark Plugs

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