13 replies to this topic

[UpperHand]

I am currently making a homemade gun, and the design is relatively simple on paper. (Although it never stays that way ) The idea has been done before, where there is a large chamber in the gun where most of the air is kept, and then transfered to a firing chamber via a ball valve. After the air is transfered, the user closes the ball valve, sealing the firing chamber off from the main chamber. Then, the firing chamber is emptied in a shot via a solenoid valve. Next the ball valve is opened again putting air in the firing chamber, and the process is repeated. The problem that I am having is that after the ball valve is opened, the air coming into the firing chamber comes in too fast, pushing up the diaphragm on the solenoid valve, and releasing the air. I was wondering what valve I should replace the ball valve with, or if you have any suggestions. I was thinking a check valve maybe, but that would probably have the same effect as the ball valve. Thanks for your help in advance,

-Upperhand

[analogkid]

You could put a flow regulator between the ball valve and the firing chamber. Also, you could put something over part of the end of the ball valve to block some of the flow. I think someone was talking about it (flow regulators) a week or so ago, I'm sure you could get one at Home Depot or, if that fails, McMaster-Carr.

EDIT: OMG same avatar!

Edited by analogkid, 14 August 2008 - 05:49 PM.

[UpperHand]

These do sound like a good device for a semi auto design, however I don't know if they really slow down the air speed. As for putting something over the ball valve, that probably wouldn't work, the air would either blow it off or the constant movement of the ball valve would twist it off. I looked around online, and it seems that flow regulators have an inlet pressure (most are above 100 PSI, which is more than I need) and a preset outlet pressure. What do you think would be a good pressure for firing darts at say, 80 to 100 foot range? Or am I asking too much with those ranges?

-Upperhand

Edited by UpperHand, 14 August 2008 - 07:26 PM.

[TheNERFArmageddon]

Your probably best off skipping the ball valve all together. let the selenoid hold th air pressure. that'll make the gun even simpler and I can almost guarantee that'll fix your problem. Som functionality may be lost, but its better that a "premature" detonation.

[UpperHand]

I really want to avoid this, seeing as I would have to repressurize the chamber after every shot.

-Upperhand

[analogkid]

I really want to avoid this, seeing as I would have to repressurize the chamber after every shot.

-Upperhand

80 to 100 feet is perfectly reasonable. I would say somewhere between 30 and 35 PSI would give the desired ranges.

[Killer 7]

I used a Flow regulator in my homemade Apocalyptic Doom

http://nerfhaven.com...showtopic=12605

Also the right pressure depends mostly on the volume of the firing chamber.
But 25-30 P.s.i. should work fine.

[UpperHand]

A few questions, first, that regulator is metal, so you had to buy a metal to pvc adapter correct? Second, could I get it at Home Depot? What about the price of the regulator?

[DTReaper]

Really all you need to do is let the air into the second chamber more slowly so the diaphram can reseat itself in the sprinkler valve. A flow valve would most likely help but you should try to let it in slowly before you think about adding on any new parts but if it doesnt go for the flow valve.

-DTR

[imaseoulman]

I can offer some possible PVC designs, but I can't be too sure without seeing your ball valve set up. One thing you can do is create your own air restrictor. Find some way to make the air flow through a 1/8" (or smaller) opening. This can be a hole drilled in PVC or a channel created in epoxy putty. If you're going for cheap, that's probably your best option.

[UpperHand]

Just an update for everyone who has helped, I tried simpler first, basically putting in a plug of sorts and drilling a 2/32" hole in it. It worked fine to constrict the air, but if problems arise in the future, I might buy a flow control valve. I also would like to mention that the main air tank is a bit of a beast, and it reminds me of the vaccum type machines that they use in ghostbusters, because I carry it in a backpack. I'll try to get some pics up if i can find my digital camera.

-Upperhand

[Quilan Fett]

http://www.plastomat...regulators.html

If your design fails.

[CaptainSlug]

http://www.plastomat...regulators.html

If your design fails.

He specifically needs a non-relieving regulator.

Which will allow you to fill your primary tank to 90psi, then have the firing tank always set to 10-30psi. This will greatly conserve your primary tank supply of air and therefore you will get more shots per fill.
That regulator also has a relatively low flow rate so it should solve your other problem.

Edited by CaptainSlug, 18 August 2008 - 11:01 AM.

[Quilan Fett]

Wait, did I post the wrong thing? If so, my mistake. But they do exist. I have one.