SpudFiles

jhalek90 wrote:Define decent pressure.

300+ psi.

http://www.youtube.com/watch?v=z-87QaU8Tpw

Test fire with a 5 ft barrel (already had it) and a home made rocket with fins.



Also, the kick at 70 psi requires me to lean into the cannon, otherwise it simply will fly backwards.

Still a normal 2" piston valve! Let's see some high pressure

No problem, its goin to be a few days before i get a new longer barrel, and a fitting to feed my friddgy with 60-120 psi on the inlet.

You probably want to keep the inlet pressure below 60-70 PSI to prevent stalling the compressor at higher output pressures.

MAN that is epic :O
Lol i want one, good job.
If any one robs you house i dont think they will ever rob it again with that thing haha

can get a 200psi vid up no barrel? just park your car on the tank to stop it rocketing off

I dunno if a car would be enough

The cannon weighs 60lb and probably wont operate at anything over 300PSI, with a decent handle there's no reason it can't be handheld

The only thing that is preventing me from using higher psi, is lack of a scrabble bumper. The piston has already been built 3 times, after destroying 3 bumpers.

1: 1/2" thick soft rubber
2: spring
3: much much stronger spring.

Part of the problem is that the piston only travels about 1".
So I need a bumper to stop it in that one inch.

SpudBlaster15 got me using my current bumper for my piston hybrid that would be more than adequate for this cannon. Neither me nor SB15 know what the thing we used as a bumper is called but both of us found it at local hardware stores.

Best way to describe it is like a baffle looking rubber gasket thingy.
If you look at this picture, imagine the baffle-ringed rubber bit in the middle of this flexible hose but 2" in diameter and proportionally shorter. I ended up buying two to use as a bumper and despite my initial impressions that it was a feeble-looking bumper, it has worked extremely well and hasn't failed me since.

Thanks Mr C.

I will look at the hardware store latter this evening.
The piston needs to be rebuilt, and I wad wondering if anyone knows how much difference piston weight, would make performance wise.

I'm thinking about using a 1/2" bolt and hardware, instead of the 1/4" bolt and hardware that keeps getting destroyed.

1/2" might be good, I use 5/16 in my pistons but they bend over time, and I'm using a lot less pressure. 1/2" would be very heavy though.

What about a plastic 1/2" piston? It would be super light, and may shatter with the wrong bumper, but it would be big enough right?

jhalek90 wrote: and I wad wondering if anyone knows how much difference piston weight, would make performance wise.

I'm thinking about using a 1/2" bolt and hardware, instead of the 1/4" bolt and hardware that keeps getting destroyed.

I have an M10 bolt (10mm) on my piston, same with SB15 as well I think.

As for weight, it probably wont make any difference. As long as it isn't ridiculously heavy, it wont matter.