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Hey everyone, I am new and just starting on my P.cannon

Posted: Sun Jun 28, 2009 4:28 pm
by Scourch
Hey everyone, greetings and all that fun stuff.

My name is Sean, and you can call me Sean, Scourch, or Newbie, whichever ya like!

That being said, I decided to make my own potato cannon. I was bored, I like things that go boom, and it's been forever since I took on a 'hands on' project. A couple days ago I bought all I needed, which was ABS piping rather than PVC. I used a 3" pipe for the barrel at about 4' long, and for the combustion chamber I used 4" piping at about 3' long. Now, as fun as that was, it was a pretty ghetto mock up. The ignition system was a piezoelectric grill igniter I bought from The Home Depot. The one I had bought came encased with a rectangular piece of steel. I am by no means an electrician, and in fact know just the basics, if that. So I couldn't figure a way on how I could keep the hardware outside of the chamber, so, I just glued it to the inside haha. Needless to say, as I fully expected, after about four or five shots, the thing was gone. So having had the experience of cementing, and boring holes, and all that I wanted to take it a step up.

So today, I went back to the Depot and bought a few extra parts. Using the left over ABS I have, as before, a 3" 4' long barrel, but my chamber I am going to have measure a total of 2 to maybe 2 1/2 inches. However I am using a different piece between my cap and adapter and the actual 4' pipe, and it is this....

Image

So on one end is an adapter with a cap, the other will be the barrel. Obviously with the adapter and that above piece attached the actual 4' ABS pipe won't be very long. Now what I did is I bored a hole in the longer part of the extension of that above pictured piece, so that the piezoelectric grill igniter will fit in nicely, which it does, but I will probably have to use some ABS cement or glue to filled in the gap. So my plan was to run my wires from my igniter out through a small hole on the sides so that little wire is exposed, then attach each end to two screws bored atop the 4' pipe, where hopefully I will have a spark.

Now fitting issues with the wire and the igniter aside... I KNOW that the spark will probably be rather weak. Is there anything I can do to enhance the current at all? Or any other suggestions for an electrical ignition that isn't very hard to install? Tazers, sadly, are out of the question as I am from MA and they are illegal to own here, so far as I know.

I hope I was detailed enough in my explanation that you all understand how my setup is. Any feedback would be great. I've seen a good portion of the potato cannons here and they are just ridiculous haha. I don't need anything quite that intense, my basic one is powerful enough for me as is haha. I just would like a better ignition system. I was also suggested a model rocket ignition, would anyone know the difference in power output between the piezoelectric igniter and the model rocket one?

Posted: Mon Jun 29, 2009 8:23 am
by chenslee
Model rocket starters rely on a thin wire getting hot and setting off a match head like chemical that ignites the motor. You would have to replace the element for each shot, or at a minimum wait until the element got hot enough for ignition. Tazers and grill starters are the way to go.

I started out with this inexpensive unit from Wal Mart:

http://www.walmart.com/catalog/product. ... id=8587363

It's 12kV output and runs off a 1.5v AA battery. It's a pain to attach a switch to and required some thought and a little dremmel-fab to get it remote activate.

Ultimatespudgun.com has a 30kV ignitor that is far superior. It has tabs for attaching a switch, almost 3x the spark power, is smaller, and has mounting holes. It is not that much more expensive and it ships faster too.