SpudFiles

Most Ignition Systems rely on sparks. But these are susceptible to gunking up. I am sure all of us have done, or at least seen it done, ignite camp fires by hooking up a nine volt to steel wool. Well, to me it sound extremely reliable. Several nine volts hooked up to steel wool spanning the diameter of the ignition chamber. EVen though the one nine volt should suffice, several more would increase the voltage of course, thus, more energy going through the small diameter threads that are the conductors.
All in all, it sounds more reliable, as it also has more surface area, more contact with the gases, so more energy to burn.

For a more professional setup, you can use a glowplug or the type seen on small model engines.

Price? Im sure steel wool is cheaper.

Yeah, but its reusable for a LONG time. The steel wool would need replacing a lot sooner. Also the wool may ignite the fuel right near the barrel, or in another not optimum place. But try it, Spudguning is about innovation.

Another innovation would be the ion propeled spud, but enough of star trekk.

Steel wool is a standard ignition method in the hobby rocketry world. Admittedly, they do it a bit different there...

1) Steel wool.
2) Oxygen (or nitrous if O2 is not available).
3) A flourescent light transformer.

It might be cool to do with a mortar style gun:
Have the 9V battery sit in the chamber, and attach a bit of steel wool to the end of the projectile.
It ignites on dropping in. Only problem is that the fuel will fly out when your projectile is not yet in place.

psycix wrote:It might be cool to do with a mortar style gun:
Have the 9V battery sit in the chamber, and attach a bit of steel wool to the end of the projectile.
It ignites on dropping in. Only problem is that the fuel will fly out when your projectile is not yet in place.

Then fill the projectile for the mortar with hydrogen, your clever enough to know why .
G's from the Dutch

Soda bottle launcher?
Thats a good idea! Holding the fuel inside the bottle, and attaching steel wool to the bottle end. Drop em in and fire!

RPG Time! You have solved my dilemma!

Steel wool has not only been proposed many times, it has been used many times.

Works fine, couple problems though. The biggest is the need to replace the steel wool for each shot. For a spark located near the center of the chamber this can be a real PITA. Often folks will mount the steel wool in the cleanout cap to make it easier to change. Great for reloading but probably not the best location for the ignition point.

One solution would be to switch to small diameter platinum, iridium, or perhaps nichrome wire. It might be possible to heat the wire hot enough to ignite propane+air without burning up the wire.

Glowplugs are made from platinum or iridium wire and survive the conditions in diesel engines. In these engines the plug does not ignite the fuel, they are just used to heat the fuel+air mixture in a cold engine.

I see a different problem - If you're using PVC, won't the steel wool singe the chamber, eventually leading to a dangerously thin chamber wall?
I think you would have to use steel pipe for this to work in the long run, but there's a problem there, too - steel is conductive, so not only would you not be sure of when exactly it shoots, you may zap yourself (if you are holding it)

Coodude26 wrote:I see a different problem - If you're using PVC, won't the steel wool singe the chamber, eventually leading to a dangerously thin chamber wall?
I think you would have to use steel pipe for this to work in the long run, but there's a problem there, too - steel is conductive, so not only would you not be sure of when exactly it shoots, you may zap yourself (if you are holding it)

Zapp yourself with a 9V battery .
You can make two contacts for the power source, those two contacts are ending in the center of the chamber(maybe with burst-disc). Drop the mortar in the launcher the the contacts (four in total) will connect and ignite the steel wool inside the chamber. Simple but effective(i hope)
G's from the Dutch, Tom

Tom wrote: Zapp yourself with a 9V battery .

how about 3?

As the only amount of time needed to ignite the chamber will be less than two seconds, by that time the 3 9v will completely disintegrate the steel wool, and by that time the combustion would have happened.