5 replies to this topic

[FromAbove]

I am finishing up my homemade Nerf rifle this weekend but there is one piece that I have yet to finish putting together; the pressure vessel. I am using a 3/4 inch solenoid valve and my question is that currently I have a 14x2 inch chamber and would like more than one shot per filling the chamber. Is this possible or will all the air escape when I trigger the valve? This question basically governs whether I will keep the chamber at 14 inches or cut that number in half.

Any help from anyone with experience with type of valve would be greatly appreciated!

[m15399]

If you want multiple shots, use the ball valve homemade in the homemades section of the site for reference on how to do this. Do not rely on how fast you can close the valve. If you want something even better, then you might want to consider building a semi auto valve. It will be more work, but it will have better results.

[davidbowie]

You can just use a big chamber and tap the trigger, but that's definitely not foolproof. A big chamber>ball valve>small chamber>sprinkler valve would be better. Or, if you can get your hands on a 3-way valve, use that instead as a semi-auto valve.

[Dr Nerf]

A big chamber>ball valve>small chamber>sprinkler valve would be better.

This is definitely the easiest to build semi-auto setup. Basically, when the ball valve is opened, it refills the pressure chamber with the air from the larger pressure chamber. If you close the ball valve, it will only fire the air in the small chamber, easily allowing for multiple shots. The pressure inside of the gun will drop, so the first shot will be the strongest.

[GeneralPrimevil]

Then, for an extra $20-30, you can go:
resv -> reg -> ball valve -> firing chamber -> sprinkler valve -> barrel

Then, just charge your reservoir to about 80psi and regulate it down to about 15-30psi. You should easily get twenty or more shots off before losing power, geven a set up with a firing chamber of 1" by 7". That would work with your current reservoir of 14" by 2". Now, you could then have a 1/2" Sch40 PVC barrel with length of 12" and still have more power than an AT3k. I mean, a heluva lot mroe power, considering you're using a sprinkler valve.

How are you activiating the sprinkler valve? Bleed switch? Pneumatic? Electric?

[FromAbove]

Thanks for all the responses guys!! gotta love the saturday afternoon pow wow.

So, I am going to keep the one chamber because it can always be removed and replaced with a more complicated set-up. I'll range test before another major design change

Holy crap, so I'm about to open my purple primer and it won't open for the life of me, so off to home depot I go.

I am going to look into something which will be the upgrade to my system...

chamber>solenoid valve>regulator>firing chamber>solenoid valve>barrel - then you could set up a spring loaded trigger with 2 momentary switches, where when the trigger is armed it would open the pressure chamber to the firing chamber and pulling the trigger would close that valve and open the valve to the barrel...just a thought from what I gather.

Anyways I digress.


GeneralPrimevil; I know that pneumatic actuation offers the best performance, but electric actuation works best for my needs right now and is just so damn sexy, so that is what I'll use for the time being.