SpudFiles

Ok, so i got my cannon fully functional but heres my new issue.

I want it to be more portable so i can shoot it at like...the beach or something.

Obviously, i cant bring an air compressor to the beach... and this leaves me with bike pump, and portable tire inflator.

I am aware that both of these will take a LONG Time to fill 2 tanks, 4 inches in diameter and 3 feet long. But thats ok with me.

The problem is, that unless i use an air compressor, the valves dont shut when i fill the tanks... Is it because the bike pump cant dump air fast enough to pressurize the diaphragm?

you can set a ball valve between the chamber and valves and a schrader in the space that is shut of from the chamber via the ball valve, then pump it up (the small volume between the valves) to about 90 psi and fill the chamber. after that you open the ball valve and shoot..

har to explain, but the valves will shut when the pump increeses pressure more for each stroke

so its basically impossible to do anything with a bike pump unless i put ball valves in

Backdraft wrote:so its basically impossible to do anything with a bike pump unless i put ball valves in

Not really, you could just pump really fast until the diaphragms are sealed

got it, you make a small (4" by 12") PVC chamber with a blowgun made to fill tires. then you pump that chamber to some decent pressure and fill the gun partly with that and then pump it up when you have got a seal.

i tried it with a 2" by 2 foot piece of pipe, ball valve to dump the air to the cannon and schrader to fill it but even at 120 psi, it wasnt enough for the large cannon.


I think i need to use 4 inch by like 3 foot at 120 psi...

My cannon has a quick connect on it, so i just attach the starter tank to it, dump 120 in it and then hopefully i can pump the rest.

Sadly its like $15 for two 4" end caps.

You could reposition your fill valve so that it fills from behind the diaphragm. that will keep the valve closed. It is simple easy and compact, just a few new fittings

Basically you just add the fill valve where you would have added a blow gun to the sprinkler valve.

A really easy way ive found to fix this is to dissect your valve, and do one or both of two things: decrease your pilot volume, or increase the resistance of your spring. To decrease pilot volume, put some carefully placed epoxy in the pilot space. To increase spring resistance, just stretch the spring... to do both, epoxy the spring into place, and use enough epoxy to reduce the pilot volume, less pilot volume means less pressure is needed to seal the diaphragm... or you can modify it, which will still have similar problems, and could possibly increase pilot volume making the problem worse... best bet is to get a regulated scuba tank... that what i bring with me, roughly 25000 cubic feet of air in a 80cf tank @4500psi.. which regulated to 100psi will give more shooting than it will take for someone to call the police... best of luck to you

will stretching the spring have any negative effects on the valves?

And the idea of a filling tank 4" by 3 foot to dump into the gun wont work?

stretching the spring wont hurt the valve...and a bike pump will put about 10% of your chamber volume into your gun at a time, meaning it will take approx. 10 pumps to get 15 psi, or 100 for 150, etc... since the small amount, the air wont pressurize the pilot volume the diaphragm wont seal.... get an ac/dc adapter for your car's cigarette lighter, then run your compressor where ever you want...

will stretching the spring make it work... im not so sure a full air compressor will work off my car lol.

Take a precharged tank with you (CO2 or maybe just your air compressor), and use that to get it seal. Once its sealed, use the pump to create the rest of the pressure.
Or just fill from the pilot area, like most piston valves need to.

read my post psycix

SpudFarm wrote:read my post psycix

And?

The ballvalve method may be better, and I know that, but I am just giving him an extra option. Repeating what you said would be parroting.