2inch piston valve problems

[superspud09]

Hi im new to this forum but not to spud guns. i encountered a problem with my barrel sealing piston valve and i cant seem to figure it out... its a 2 inch t and a 1 1/4 coupler filled with hot glue for the piston. when i fill the air chamber the valve seals air perfectly but when i hit the pilot the valve does not open what is wrong here? help would be greatly appreciated


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valve closed


my piston


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[Matt_NZ]

when i hit the pilot the valve does not open what is wrong here? help would be greatly appreciated

Hey,

What pilot valve are you using and what is the volume of the pilot?

[superspud09]

Im just disconnecting my air line for the pilot for now..volume is about 4.7 cubic inches

[Lockednloaded]

You need a much better pilot, or much less pilot volume

[superspud09]

You need a much better pilot, or much less pilot volume

would a 1/2 inch ball valve do the trick?

[Fnord]

The less difference there is between the port diameter and the piston diameter, the faster your pilot needs to be.
This is because there isn't much force acting on the small exposed surface area. You can avoid this by making a better seal between the pilot volume and chamber(o-rings), or using a bigger pilot valve.

I would hope a 1/2" BV would do it, but if it doesn't try adding an o-ring.

[Gun Freak]

A 1/2" ball valve should suffice or upgrade to a larger valve like a sprinkler valve or a smaller piston valve. Also, why did you full the piston with hot glue? It only makes it heavier and moves slower, and you could have just used plugs to make it lighter.

[superspud09]

You can avoid this by making a better seal between the pilot volume and chamber(o-rings), or using a bigger pilot valve.

Will air be able to get past the o-rings to fill the chamber?

[Gun Freak]

Well you can use a floating o-ring or it will be like my piston in which the o-rings only make a tigher fitting piston while still letting air get by.

[Fnord]

Yes, if you put a tiny hole in the piston to bypass it, or if you make a floating oring design. Chances are you won't need to do either since I doubt your first attempt at using orings will seal perfectly. It took me at least 2.546 *10¹⁵ attempts to get it right without a lathe.

[superspud09]

Thanks for the help guys im going to put orings in and try the ball valve for now

[SpudBlaster15]

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[clemsonguy1125]

If you have issues with the O-rings, glue craft felt around the piston, it compresses as you slide the piston in. Medical Tape also works well.