19 replies to this topic

[Papershruiken]

Okay. So I'm looking for an air valve for a potential automatic homemade. Obviously I've googled it and I can't find what I'm looking for, so this is the next best thing. Anyways...
I need a valve that releases air when a desired pressure is reached. It's similar to a pressure release valve, but those wouldn't direct all of the airflow into a barrel or something similar. Any ideas?

[Buffdaddy]

Okay. So I'm looking for an air valve for a potential automatic homemade. Obviously I've googled it and I can't find what I'm looking for, so this is the next best thing. Anyways...
I need a valve that releases air when a desired pressure is reached. It's similar to a pressure release valve, but those wouldn't direct all of the airflow into a barrel or something similar. Any ideas?

Magstrike/RF20 pistons work like this; the spring holds the chamber closed until there's enough pressure, then releases the air. Search and browse through things for more ideas on making something similar. Here's a good pic:


More ideas that could be adapted, or at least contain some principles with potential:

Roboman's SCUNBAG

And similarly (or possibly better yet):
Homemade Paintball breech

Obviously, you would need to adapt that to fire darts, preferably from a clip.

Edited by Buffdaddy, 11 April 2012 - 10:44 AM.

[Curly]

I personally find full auto overrated, especially in a game where blasters are often preferred for their power and not their ROF. You could use an OPV to pilot the airtank, but it wouldn't have enough air dump. Zorn suggested using a OPV to pilot a tiny backpressure tank which pilots the firing tank. While effective that would be very difficult to build.

Instead the solution I would rather is using a valve to control flow from the firing tank to the backup tank. Some push-button valves would allow you to get a couple darts per second out depending on the airflow. This setup also doesn't waste air like full and semi auto blasters.

If you're just wanting the full auto for the shenanigan factor, then a bigass HAMP would give you a few shots from a hopper at a time, or you could use a leafblower like Ryan mcnumbers did in a video.

[Buffdaddy]

I personally find full auto overrated, especially in a game where blasters are often preferred for their power and not their ROF. You could use an OPV to pilot the airtank, but it wouldn't have enough air dump. Zorn suggested using a OPV to pilot a tiny backpressure tank which pilots the firing tank. While effective that would be very difficult to build.

I can think of many situations where a long-range, full auto would be handy. Had there been a SGNerf brass breeched Stampede in my hands at Apoc last year, there were many times you had groupings of people just begging to be shot, and the full auto would have been ideal. I'm assuming range, accuracy, and RoF are all there, of course - just using an RF20 would have been suicide.

Springers can do this already. But decently easy to make airguns? That would be a really cool development.

Edited by Buffdaddy, 11 April 2012 - 03:44 PM.

[Papershruiken]

I planned to have a large air resevoir tank made of PVC and endcaps, then attach it to the firing tank. You could have a semi-auto if you attached a barrel system straight to the firing tank, but ideally the valve I'm looking for would release the air when a certain pressure is reached behind it. This way, when the trigger is held down the air won't just blow through, it actually gives it a chance to pressurize. If you wanted both, you could set up some ball valve system.

Edited by Papershruiken, 11 April 2012 - 04:06 PM.

[mysterio]

If you want full-auto, hopper an RF20 piston. Easy as pie. Just use CPVC to PVC couplers, or a DMK wye.

[Papershruiken]

If you want full-auto, hopper an RF20 piston. Easy as pie. Just use CPVC to PVC couplers, or a DMK wye.

That's a good idea. I'm going to try this, and post results later. Gracias!

[Buffdaddy]

If you want full-auto, hopper an RF20 piston. Easy as pie. Just use CPVC to PVC couplers, or a DMK wye.

THAT'S NOT HOMEMADE.

[mysterio]

THAT'S NOT HOMEMADE.

Then use the homemade version!

[hamoidar]

If you want full-auto, hopper an RF20 piston. Easy as pie. Just use CPVC to PVC couplers, or a DMK wye.

I don't think that would work, simply because the RF20 piston puts out a tiny amount of air.

[Buffdaddy]

I don't think that would work, simply because the RF20 piston puts out a tiny amount of air.

You can switch out the spring inside the piston and make it reach a higher pressure before it fires. Slows RoF, but ups range.

[hamoidar]

You can switch out the spring inside the piston and make it reach a higher pressure before it fires. Slows RoF, but ups range.

Still, I don't think it would be enough air to make a hopper function properly. Simply increasing the power will not increase the air output.

[Buffdaddy]

Still, I don't think it would be enough air to make a hopper function properly. Simply increasing the power will not increase the air output.

It's increasing the pressure without changing the volume (or in this case, the final volume at the point of firing). By definition, that's increasing air output.

[thedom21]

You could just take this and make it bigger so it works nicely with a hopper, the setup of a magstrike/rf20 piston is begging to be clipped. I guess I might try this and see the results. I believe he has a write up somewhere on the forums.

Edited by thedom21, 11 April 2012 - 10:32 PM.

[KoRnEd]

Still, I don't think it would be enough air to make a hopper function properly. Simply increasing the power will not increase the air output.

Hamoidar, Mysterio has a working version of this, and hits 50's easy. I don't know how you can assume it doesn't put out enough air when you've never tested it.

[mysterio]

If you needed it.

[BOSS9]

You can always expand the tank.



this is a Magstrike piston, which is much smaller than an RF20 piston, but it also gets roughly 60s at stock pressure (stock spring). I'm sure the results would be more impressive if this were done to an RF20 piston.

[hamoidar]

You can always expand the tank.

this is a Magstrike piston, which is much smaller than an RF20 piston, but it also gets roughly 60s at stock pressure (stock spring). I'm sure the results would be more impressive if this were done to an RF20 piston.

Okay, okay, I stand corrected. I may just have to do this to my RF20.

[shardbearer]

A couple years ago on Spudfiles someone attached a QEV (industrial backpressure piston valve) to an OPRV. Worked amazingly well, ridiculous RoF (2400-2500 rpm), you can attach as big a tank as you want, but it ate up an huge amount of air. A fire extinguisher at 400psi gone in 30 seconds. A smaller version of that would work pretty well for Nerf though.

[Buffdaddy]

The Supersoaker Shotblast works about like the same way too.
You have to keep enough of the shell for the original automatic trigger to work.
Pressure goes in and builds up and as soon as the spring gets moved far enough the piston pulls its own trigger.

I found this thread on nerfHQ, I hope linking there is okay.
Inside is lots of details on Supersoaker Quickblast which works just like Shotblast.
http://www.nerfhq.co...hp?topic=8615.0

I hadn't had a chance to play with these yet, and that might be our solution. We'd need to find a way to increase pressure before firing, with a stronger spring on the piston or such, but take an airline from a tank or bladder to the tank, add a Magstrike trigger or such, and you'd have your solution. I shall do this now! hahaha