SpudFiles

Piston valve is housed in a 2'' T, the porting is 1.9'' (1.85 actually)
The valve seat to piston diameter ratio is VERY close to 1/1

The pilot is a 1/4'' QEV, piloted in turn, by a 1/4'' ball valve.

The chamber is a old diving tank, aprox 1000 Cubic inches in volume.

The cannon weighs over 60lbs, and still kicks like a mule with no projectile, or barrel for that matter.

50 PSI shot.
[youtube][/youtube]
(the blast knocked over two, 2'' porting coaxial cannons in 4'' PVC that were retired do to shattered end caps. )

NEW: projectile shot.
[youtube][/youtube]




The max pressure i have used so far is 70 psi. Hearing protection is a must at anything over 15psi. I do plan on playing around with higher pressures, possibly several hundred psi. The bottle was hydro tested to 2800 psi.

On a side note, the first time i fired it, was at 40 psi. The muzzle was pointed, by accident, at a beer bottle about 10 ft away. The bottle exploded where it stood. Turns out the welders left some "slag" in the bottom of the bottle, which exited quickly out the barrel port.

Wow! Nice job! The tank could do with a paint job, but other than that it looks excellent!

Paint is the next thing on the list.

Also, this was a video of that tank with a 1/2'' porting valve at 100 psi.

http://www.youtube.com/watch?v=6Wq4gzX1Rw4

Can't wait to see the paint job. Nice job with the 1/2" porting one.

I am also going to add a 6-10 foot tennis ball barrel, complete with bipod.

You should take some diesel fuel and rub it on that tank. Some guy did it to his car and it turned the rust black, giving it an old bomber look. As long as you then have a rust inhibitory clear coat you should be good to go. I would try to continue with that worn/ distressed construction machinery look. It would set it apart from the crowd.

Also, why not pilot the 1/4 QEV with a blowgun? I'm sure you would retain the same performance while upgrading the comfort of firing the valve.

Dude that thing has some serious power!!! I cant wait to see damage pics!! Awesome job!! What are you planning to use for a barrel???

Looking very promising, can't wait to see this at decent pressure

Looks great! Looking forward to some high pressure videos.

Any reason you went with the current configuration and not an over-under?

Define decent pressure.

With 1.9" porting, 50psi has already shot a 1.75" Hdpe round through 1/2" pressboard, with no barrel, and the projectile simply set in the threaded barrel port.

I will go up in pressure, but very slowly ad this thing is a boss at as little ad 50 psi, and I don't have a barrel yet.

MrCrowley wrote:Looks great! Looking forward to some high pressure videos.

Any reason you went with the current configuration and not an over-under?

Simply to avoid buying a 2" elbow. Also, I plan on a long barrel and a bipod, which should help the looks.

Very nice, but I think the elbow would be a worth while investment for the chamber position.
Also keep in mind that as long as you're only using sub-150psi pressures, you won't be exploiting the true power, sso you'll have to pump up the pressures to really set it apart from every PVC 2" valved gun on this site

This thing is a monster! Slap a ten foot barrel on it and let's see some damage! Might I suggest bolting it to something very heavy? Looks like it'll put you on your back with a tennis ball.

What is the leak from in the video? Anyways this thing is shmexy can't wait for higher pressure shots, bolt/washer pistons FTW!!

Awesome !
Piston looks like a beauty

VERY much looking forward to high pressure shots....

jhalek90 wrote:The chamber is a old diving tank, aprox 1000 Cubic inches in volume.

Looks to me like a standard "80" size tank. If so, it would be around 659in^3.

I do plan on playing around with higher pressures, possibly several hundred psi.

Be aware that if the valve is fast, a large bore with a CB ratio that large and high pressure causes the canon to act like a rocket engine when fired. Expect serious secondary recoil!