I started a thread on solid fuels over at APC a while ago with the intent on making a charcoal powder fueled cannon from steel tube. The exact design I was going to use is a little beyond what forum rules permits, but it involved igniting the charcoal in the same step as dispersing it.

Aluminum ...

A grape chunk shot back at you from the direction it was flying? With enough force to leave a welt?

Through up to five layers of what?

There's no reason for things "exploding" in mid air. Are you sure it isn't just breaking up in the barrel and the chunks just aren't separating noticeably until several meters out? That would make much more sense.

Edit: Crowley posted first, darnit.

You felt the need to start a thread about this?

Just look around at all the other "help me" posts, there are plenty.

PVC pipe isn't very pure PVC. Someone on APC tried to use PVC pipe in place of pure PVC as a chlorine donor in a star composition, but it didn't work. Casting it might be difficult if there are different materials that may change the properties of the pipe once it is in it's shape. If you want to ...

This would be a lot more trouble than it's worth. You would probably be better off dissolving the PVC in something, then pouring/pressing it. If you wanted to try sintering you might get somewhere.

I started a thread over on APC a while ago when I was going to make a charcoal powered cannon, and now that I have summer off I might finish it.

These are quite viable fuels if you can ignite them and spread them effectively. We are supposed to stay out of pyro-related things on this forum, but I ...

Well, you could freeze the potato to harden it and then turn it on a lathe to 1.5", then you get some oxygen…

If you put a piston valve on a pneumatic of those dimensions you should be throwing stuff pretty far out there. Spray your projectile with glow in the dark paint and fire a little after ...

Perhaps someone like a senior member on here could go on as an "honorary mythbuster" like they sometimes have on. I agree with distancing spudguns from this, call it something else so people think of it as something that is out of their league so idiots don't attempt it.

Save some work, go for an oxy-fuel cannon if you have access to oxygen. Just find a way to weld a buffer in the middle of the pipe cut out of .25 or .5 inch plate. If you have access to acetylene, even better!

(wow, first post in about six months)

Heh, the funniest accident I have seen happened to my friend when he was shooting my combustion. He had the back propped kind of high on his shoulder and started pushing the igniter, but nothing happened. He turned his head to look at me and started saying that it wasn't working when the back lifted ...

You can use pretty much anything short of solid fuels or multiple atmospheres of hydrogen or acetylene.

If one were to dip part of the SW in gas before firing, that would probably increase the chances of ignition. The steel wool I have been using doesn't spark, maybe that's why the torch didn't light. I have been using it as an extender for homemade black match which gave me the idea.

Same as mister steve here. I just felt like launching something and I ended up building a cannon.

If you're after more guranteed ignition than a BBQ igniter, stop messing around with the plain steel wool. I have held an unlit running torch against a wad of burning steel wool and it didn't ignite. It is, however, capable of lighting something like gunpowder mixed with a binder or KNO3 and sugar ...