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will this exaust system work?

Posted: Sat Jul 01, 2006 12:29 pm
by djt
i was wondering if my exaust system for my coaxil gun will work. below are some pictures of a failed attempt at a coaxil piston gun. (dont ask about all the couplings). i think the problem is my piston not sliding well enough. i am going to scrap the gun and i am going to make another one like it with a better piston and some other improvements. My question is whether (sp?) to use the same exaust system for my next gun. The air exausts out of the blowgun on the bottom of the gun after traveling through two elbows. the shrader valve and gauge are placed on opposite sides of a T after the blowgun. Since this will be used for only a 1.5 or 1.24 inch piston do you think it will work for a coaxil piston gun?

Posted: Sat Jul 01, 2006 4:54 pm
by carlbelcher
It should work just fine. Just keep in mind the more pipes/piping the exhaust was to travel though the more resistance it faces. The resistance your exhaust faces the slower your valve will move.

Posted: Sat Jul 01, 2006 6:14 pm
by Benny
that is a bloody lot of pilot space for a small , defenceless blowgun to exaust, try a modded sprinkler valve.
ps: what exactly was wrong with this one?

Posted: Sat Jul 01, 2006 6:29 pm
by Velocity
Well it MAY work... but there are a few reasons why it probably will not

1) The pilot volume is too big. The blowgun needs to exhaust ALL of the air in the pipes connecting it to the pressure gauge and actual gun, along with the volume behind the piston.

2) The pilot valve is too small. That blowgun looks like one of those 1/4" npt in, small opening out models. It just cannot exhaust the air quick enough, especially not with all of that pilot volume.

Heres what I would do:

Take a 3/4" iron pipe nipple and screw it into the cannon behind the piston. Then, attach a 3/4" sprinkler valve. Mod the sprinkler, and you should be fine

Posted: Sun Jul 02, 2006 11:23 am
by djt
i would use a sprinkler valve but this is just one of those guns that costs like five bucks and uses a whole bunch of spare parts around the garage. i dont want to spend the money for a sprinkler valve on it.

and benny i think the piston doesnt slide well enough. i sprayed a bunch of wd-40 down there before i put the piston in and closed it back up. it just kind of gets stuck or something. it could also be a combonation of a heavy piston (solid epoxy) and weak exaust system.

Posted: Mon Jul 03, 2006 11:01 pm
by noname
Use at least a 1" ball valve for all that exhaust. A blowgun just won't cut it.