Oh boy, I think I'm gonna blow my cannon apart!

[Technician1002]

It's finally coming together! I just need to make the wooden supports and I'll be done. My jigsaw is broken so this might take a while though...


I was testing the piston with only 15 PSI in the chamber, and when I pulled the trigger it let out a loud BOOM!!!. No funny noises or delayed hissing. It was instant. Good thing I had the bumper in there.


I'm going to attach a miniature sharpie to the bumper so I can see how much the spring compresses.

Congratulations on first pop.

On my 2 inch first test was at about 30 PSI in the house.. I about had to go change underwear. I didn't think 30 PSI would do that. You will want a good bumper. Enjoy and again congratulations.

[jmccalip]

Congratulations on first pop.

On my 2 inch first test was at about 30 PSI in the house.. I about had to go change underwear. I didn't think 30 PSI would do that. You will want a good bumper. Enjoy and again congratulations.

Thanks.

And thanks for helping me.

It's kinda scaring me at 25 PSI. I used to have a 4', 4" chamber sprinkle valve cannon triggered by the solenoid only, and all it did at 50 PSI was make a pitiful farting noise with no recoil. The piston cannon is a monster compared to this, even at 25 PSI.


It does have a fair bit of recoil. I can picture in my mind the 90 degree elbow snapping off, but maybe I'm just paranoid.


It leaks slightly out the barrel with my PVC piston. I think the pressure is seeping through the bolt/nut in the middle. Should be an easy fix.


Do to the weight on the pilot side, I need a separate support for it.

[Technician1002]

It does have a fair bit of recoil. I can picture in my mind the 90 degree elbow snapping off, but maybe I'm just paranoid.


It leaks slightly out the barrel with my PVC piston. I think the pressure is seeping through the bolt/nut in the middle. Should be an easy fix.

Be sure to use a spacer and tie the barrel down. You don't want barrel whip from breaking things.

As for the leak, Put some air in it, Tip it up, and pour a cup of water in it.

No problem seeing where the bubbles come from now.

[jmccalip]

It does have a fair bit of recoil. I can picture in my mind the 90 degree elbow snapping off, but maybe I'm just paranoid.


It leaks slightly out the barrel with my PVC piston. I think the pressure is seeping through the bolt/nut in the middle. Should be an easy fix.

Be sure to use a spacer and tie the barrel down. You don't want barrel whip from breaking things.

As for the leak, Put some air in it, Tip it up, and pour a cup of water in it.

No problem seeing where the bubbles come from now.

Put a spacer where? There is only an 1/8" gap between the tee and elbow. Maybe everywhere there is a gap, I guess it couldn't hurt.

I plan on 2 or 3 wooden supports with metal cable ties for the barrel, reinforcement for the 2" fitting coming off the tee, and a final support for the pilot.

I'll just hold off until I get the entire thing assembled, and then you guys can OK it.

[Technician1002]

Put a spacer where?

When you attach the barrel to the valve it hang over the chamber.. Tie it down.

I'll just hold off until I get the entire thing assembled, and then you guys can OK it.

Maybe a good idea

This guy has his barrel tied down well.
http://www.spudfiles.com/forums/the-spu ... 17850.html

[dewey-1]

Looking good so far!

I recognize that flow control regulator.
That one is from Harbor Freight.
They work great as a fill port valve due to the small size.
I use one on each cannon that is built.
I even did a 3D drawing of it.

Have fun with that valve!

[jmccalip]

Ok, I got every assembled and ready to fire. I just need some lube for the o-ring and maybe a cool paint job. I'm thinking maybe gray fittings and black tube. Any thoughts?


Also, how do you KNOW if your bumper is going to work at high pressure? I use a 5" long 80lb spring, and 2" of a foam pool noodle. How can I be sure at 60PSI, so I don't blow myself apart?

Maybe a better question, what have you used successfully as a bumper for a 2" piston.

[inonickname]

Ok, I got every assembled and ready to fire. I just need some lube for the o-ring and maybe a cool paint job. I'm thinking maybe gray fittings and black tube. Any thoughts?


Also, how do you KNOW if your bumper is going to work at high pressure? I use a 5" long 80lb spring, and 2" of a foam pool noodle. How can I be sure at 60PSI, so I don't blow myself apart?

Maybe a better question, what have you used successfully as a bumper for a 2" piston.

Place it on a flat surface, put some plywood over it and smack it with a mallet or hammer. You'll soon see if it's good enough.

[jmccalip]

Here's a sneak peak.


I test fired into some unsupported 3/4" plywood and it went right through at 20 PSI. At 40PSI, it went about 1/2" into a solid 2x4.


I had a spare 4" sch40 coupling and reducer that I machined down to slide perfectly over the 2" male/female adapters and 3" tee connecting the barrel. It's solid as a rock now. This insures that mishandle or barrel snap will not damage the delicate 2" threaded fittings.

Complete with adjustable hop-up. I'll have to test it in the open field to verify how well it works.



The problem is the cannon is LOUD when it fires. The sound is just a huge piercing crack...I don't want to attract unwanted attention.

[Technician1002]

The problem is the cannon is LOUD when it fires. The sound is just a huge piercing crack...I don't want to attract unwanted attention.

A longer barrel will quiet it down considerably along with lower pressure. In a test, I tried an overly large barrel on the marshmallow launcher and launched a tennis ball at 110 PSI. The clank of the valve is noisier than the actual shot.
[youtube][/youtube]

The tank, not shown in the video is the 54 cubic inch marshmallow cannon.