Potato Cannon Build

Hello everyone!  We've been wanting projects for the group to work on at meetings and we decided that building potato cannons would be a great project.  It's relatively inexpensive, pretty easy to build, and tons of fun.  We plan to have everyone build these cannons, and then meet up over the weekend for a big group potato cannon bash.  If you aren't interested in the build, definitely stop by the meeting anyway to hang out and have a good time.  If you want to participate and build your very own potato cannon that you can love and cherish forever, then here are the details you will probably want:

What is it: A potato cannon (aka spud gun) is a simple cannon that shoots potatoes.  There are many types and variations of potato cannons.  We will be making a simple combustion cannon.  This means that it will be powered by lighting a flammable gas in a small chamber, essentially creating an explosion.  The explosion will cause the potato to shoot out of the barrel at high velocity, thus giving everyone a wonderful time.  Our cannons should similar to the one in this video I found, although our results may vary: http://www.youtube.com/watch?v=8caW9dVcq3c

Price: The price may change a bit depending on how many people sign up for this project.  Expect to pay at most $30.  Please bring exact change.  We don't have a cash register.  Giving change may be impossible in which case, you will either have to donate the extra money to Heatsync Labs or not participate.

Signup: If you want to sign up for this build, then please RSVP to me, RickO before 5:00AM on Thursday, Sept 17.  Please make sure to include your full name so we know who you are when the time comes.  We will have to pay for all of the materials up front out of our own pockets and the total may very well be a few hundred dollars depending on how many people sign up.  If you sign up and then do not show up or do not pay, your $30 comes right out of our pockets.  We are not rich.  Please do not RSVP unless you intend to pay us the $30.  If you have to cancel then please do before 5:00AM on Thursday, Sept 17.

Materials: As long as you pay the $30 then we provide all of the materials you need.  This includes PVC, Primer, Cement, Ignition system, everything.  The only things the price does not include is projectiles (potatoes) and propellant (aerosol spray).

Tools: We should have all of the tools required, however if you have tools you would be willing to share at the meeting, it would be great if you could bring them.  This will help make the builds go faster and there will be less waiting for tools to become available.  Here is a list of tools that we need:

1. Power drill with 5/16" drill bit and 1/2" drill bit
2. Hack saw

The tools do not have to be anything fancy, they just have to work.

Skills: Anyone with two hands should be able to build a potato cannon without a problem.  And even if you do have a problem, you will have plenty of people there to help you out.  For this build you will most likely need to be able to cut PVC with a hacksaw, drill a few small holes with a power drill, and solder a few wires together.  The rest of it is just cementing/taping things together.   Remember there will be lots of people around and available to help you out so don't be discouraged if you think something might be a bit too difficult.

I believe that is all of the information you should need.  If you have any questions, let me know and I will do my best to answer them as timely as possible.  Hope to see lots of cannons being built at the meeting on Thursday!

EDIT: I forgot to mention that you may want to wear clothes that you don't mind staining.  PVC cement and PVC primer can stain your clothes and be impossible to get out.  The last time I uesd it, I didn't have a problem but you never know.  I don't want someone staining their favorite shirt or something.

EDIT 2: Changed the drill bit sizes above due to a different, more simple firing mechanism I was able to find.  I also removed the soldering iron from the tools needed for the same reason.