I get a horrible image in my mind of that tank blowing up... Anyways, with a tank that size, I'm thinking I'd probably only need around 150PSI to get around a dozen shots (if not more?).

I actually have a like, 50gal+ air tank... Think it would fit on a golf cart? Couldn't I just pressurize it really high and refill my chambers every shot?

What size of chamber would you suggest for multiple shots? The only places I can use this is on my friends dock (where I can use an air compresor) or on a small island behind my house (no pumps available)

If I have 2 2"x3' air chambers and I fill them to around 80 PSI, could I get multiple shots out of it? If not, what pressure would I need?

Here it is so far! The 1" PVC I found wasn't actually 330PSI, that was 3/4". I put the non-pressure rated 1" in (just to see what it would look like, without glue) and it looks about Schd 40 thickness, but it wouldn't be a good idea to use, right? Anyways, all I need now is 2" PVC, 1x1-1/2 bushing ...

I actually just found 20' of 330PSI 1" PVC pipe. Do you think make a few chambers out of that could save me some money (I'm extremely tight on cash right now)? I was thinking since I wouldn't have to buy 2" bushings, 2" PVC, or 1-1/2 male adapters, I have a little moola left over. Any thoughts on 1 ...

I just bought my sprinkler valve today, and I think I'm going out to get the PVC parts tomorrow. I made a plan for it. Tell me how it looks (I know it's not perfect, but it's 1 a.m. and I'm lazy).
http://i118.photobucket.com/albums/o99/geekfreak194/PotatoCannon-2.jpg
If you don't understand ...

Actually, the only problem I made was not centering it perfectly... I know how sloppy my J-B Welding (?) is, but I'm not here to make a pretty cannon (I'm good enough for the cameras)... Aside from horrible humor, here are my pics...
http://i118.photobucket.com/albums/o99/geekfreak194/DSC00043.jpg ...

I just bought a Rainbird CP-100 today for my pneumatic valve. When I was tapping the hole for the blowgun/nipple, I split the plastic. I filled the crack with quite a bit of J-B Weld (along with the nipple), but will that be enough to keep air from leaking out? Any help would be appreciated. Thanks ...

Well I put on a 3 foot barrel and tested it yesterday. I got 2 or 3 shots out of it, when the back of the chamber blew of, hit my arm, they continued into some bushes maybe 25 feet away... lol. It wasn't damaged, so I just cemented it back on and tested it again. This time the chamber cap just ...

Ok, I can't find batteries anywhere for my camera, so no pics for awhile... I did a test shot with the cannon on the ground with 1 of my feet on it to make sure nothing would pop off, and it was fine! But, after that, my lantern lighter broke (sort of) so I might look for a new ignition source. I ...

I'm trying to find my camera. When I do I'll post some pics!

Would it help to seal all the attachments with the silicone stuff?

To keep the lantern lighter (my lighting method) in place and to seal it, could I use a silicone based sealant that is made for plumbing?
P.S. Thanks so much for all the help (except the part about PVC not showing up on X-rays... thats scares me...)

But I can just make the 12" barrel, and then cut it down and put the adapters + the right length barrel later, right? Oh ya, almost forgot, I'll post some pictures once I drill the hole for the sparker. I might spray paint it green, would that be cool or not?