22 replies to this topic

[davidbowie]

I'm surprised to see that so many of the valves in use on homemades (PVC ball valves, Sprinkler valves w/ BLEED, etc.) are rather primitive.

As an active member of the spudgun community, I think you guys should check out some of the valves we know and love.

Piston valves:

http://www.spudfiles...hp/Piston_valve

Diaphragm valves:

http://www.spudfiles...Diaphragm_valve

QEV's (quick exhaust valves):

http://www.spudfiles...k-exhaust_valve

Sprinkler valves (use them the right way: mod them):

http://www.spudfiles...Sprinkler_valve


I apologize for simply parroting these descriptions from another site, but they offer much more well-written and in-depth descriptions than I can.

[cxwq]

Most of us are aware of those technologies, but the air volume required to fill a foot long, half inch diameter barrel is orders of magnitude less than that required for spud guns. Those valves/modifications are a response to the specific need for large air volumes and wouldn't necessarily be any better for nerf.

Besides that, homemade nerf has (long ago) gotten to the point of being limited by the projectile itself, not the launching mechanism.

Welcome to NH though.

[DX-Robert]

What I find interesting is that Nerfers still use PVC ball valves when building a basic ball valve homemade. Metal ball valves are much, much faster and can be screwed in, unlike PVC ball valves which usually must be glued on and are slow as hell. Some in water warfare ditched PVC valves a long time ago. I have finished several PVC homemades [5 for water, 2 for Nerf] and all are practical on a battlefield because they use faster and easier to flip metal valves. My first ever homemade had a PVC ball valve and I don't use that gun anymore because the valve is too slow. Why haven't metal ball valves been used in Nerf yet?

[CustomSnake202]

People do use metal ball valves too, you just don't see them on the site too often. I used a brass ball valve for a homemade, and it does work a little bit better than a PVC valve. Better handle and release. Only downside is that metal vavles cost a lot more, and ball valve guns are generally inaccurate as hell. That's why people go to a hose-sprayer attachment or homemade valves to increase accuracy.

[man with many guns]

Metal valves haven't been used because you would have to thread the pvc, and that wouldn't work.
Those valves would be to big to be practical in a nerf war. And if you did get it small enough to work, you would have to fill it with an air compresser, which plain and simple, wouldn't work.

Edited by man_with_many_guns, 29 November 2005 - 07:03 PM.

[CustomSnake202]

Metal valves haven't been used because you would have to thread the pvc, and that wouldn't work.
Those valves would be to big to be practical in a nerf war. And if you did get it small enough to work, you would have to fill it with an air compresser, which plain and simple, wouldn't work.

First off, you can get pvc attachments or fittings if you will that are already threaded, so you would just cement that on the end and screw on the vavle. Second, why would you need an air compressor? It works the same as a PVC valve.

[DX-Robert]

Metal valves haven't been used because you would have to thread the pvc, and that wouldn't work.
Those valves would be to big to be practical in a nerf war. And if you did get it small enough to work, you would have to fill it with an air compresser, which plain and simple, wouldn't work.

You can get common fittings with threads to screw into a metal valve. A pair of male adaptors work best with thread seal tape. Again, there is no need for any cement with threads. And how are metal valves too big to be practical? You can get them in any size you could get a PVC ball valve. The smallest I've seen is 1/2" and I most commonly use 3/4". Also, you don't need an air compressor. A simple schrader valve with a bike pump works best.

Only downside is that metal vavles cost a lot more, and ball valve guns are generally inaccurate as hell. That's why people go to a hose-sprayer attachment or homemade valves to increase accuracy.

PVC valves cost around $5, metal valves cost around $7-10, at least in stores here in Northern NJ. There's not too much of a price difference, and it is worth it for a valve that is easy to attach and flips 2-3x faster than a PVC valve. I've seen metal valves on sale for $3 once, though.

And I don't get the accuracy part. The user makes the gun inaccurate, not the gun itself. I'm not that bad with a ball valve homemade. I'm much more accurate with that than with a Maverick.

[davidbowie]

The big advantadges of spudgun valves are that they are compact, and, for the most part, can be triggered by blowguns, which make excellent triggers.

Ball valve guns are so inaccurate because you have to move your entire forearm to open it. Most of the time, this arm is also holding the gun, meaning you jerk the gun when you fire.

the air volume required to fill a foot long, half inch diameter barrel is orders of magnitude less than that required for spud guns.

1) many of my spudguns, and those of many others, have barrels about the size you're talking about. Still, a valve with a quick opening time and decent flow helps.

2) ball valves have the most possible flow. It is physically impossible to have higher flow than a ball valve. The issue is that they open so slow that for most of the shot, the valve is barely cracked open.

Actually, now that I think of it, a high-flow pistol grip blowgun would be a decent main valve for nerf. it has similar flow and open-time to Boltsniper's new cool valve, yet it's already a finished pistol grip. I should try this out sometime.

[Dr Nerf]

I'm surprised to see that so many of the valves in use on homemades (PVC ball valves, Sprinkler valves w/ BLEED, etc.) are rather primitive.

I would have to agree with you. Many people just use ball valves. But not everyone uses bad valve choices. It built my own homemade with a homemade valve that works similar to the way that a piston valve works. If you want more information about that, go here.

2) ball valves have the most possible flow. It is physically impossible to have higher flow than a ball valve. The issue is that they open so slow that for most of the shot, the valve is barely cracked open.

Ball valves are just about the worst choice for a valve. They open so slowly. I would never use a ball valve unless I have a massive pressure chamber with a long barrel.

[Talio]

I really have nothing to add to the conversation, but as the community douche bag, I'd thought I'd step out of my position for a second and thank you for dropping by and giving the information. Homemade nerf has become more of a "oh that's cool" thing rather then something anyone takes real seriously. We have a few, Boltsniper leading the way that I would say have made some cool stuff. Well Bolt is in a league of his own, but other guys have made legitimately cool stuff. Past that it doesn't seem like it has much purpose in the community.

With that said, I think it's awesome that you dropped by and I'd love to see you stay around. We always need guys who really know what they're talking about when it comes to homemade projectile launchers. So I'd like to give you a personal welcome on top of CX's and thank you for stopping by and being so civil.

Talio.

[davidbowie]

Thank you Talio, and really everyone, for your warm and welcoming replies.

Dr. Nerf, that's a nice gun! The bolt action is well done, and an integrated onboard pump is a really nice addition. How is your valve built?

Another, somewhat related question:
does 1/2 thin-wall pipe (aka 1/2" SDR 21) fit any sort of stefan decently?

I ask because I have a propane-metered gun 98% complete, with a 1/2" thin-wall barrel (perfect paintball barrel), and a nerf set-up would be a nice addition.

[man with many guns]

I was talking about David's valves being to big.

[DX-Robert]

Ball valve guns are so inaccurate because you have to move your entire forearm to open it. Most of the time, this arm is also holding the gun, meaning you jerk the gun when you fire.

I don't understand that second part. I always place my right hand under the pc, my left hand on the valve handle. At least in water wars homemade operation is hold with the right, fire with the left, which gives me accuracy equal to a normal trigger. You could screw in the valve the other way so that it fires with a backward flick with the right hand, but one gets used to left handed flicks very quickly.

Ball valves are just about the worst choice for a valve. They open so slowly. I would never use a ball valve unless I have a massive pressure chamber with a long barrel.

That's what all of my homemades entail, yet they are nearly equal to the speed of pressing a trigger. That's why I raised the metal ball valve issue. Many Nerfers here get the impression that ball valves are horribly slow, but that's because there's nothing but PVC valves in the homemade articles. PVC ball valves are horribly slow. Metal valves are horribly fast. Done deal.

[davidbowie]

You would be surprised how slow ball valves really are. It's all a matter of milliseconds (metal ball valve is about 90 if your hand is quick, modded sprinkler valve is more like 16), of course, but if your projectile is going over 250 fps (pretty slow for a decent airgun), your projectile is out of the barrel in about 30 milliseconds (for a 1 foot barrel). A solenoid valve isn't fast enough, but it's a lot better than a ball valve.

I'm not exactly sure about the numbers, but if my memory serves me, theyre pretty close to right.

Edited by davidbowie, 30 November 2005 - 08:00 PM.

[KirbySaysHi]

I realize I'm joining in the conversation late... BUT!

Last summer I built a "nerf" gun using PVC and a blow-gun-modded sprinkler valve. It's only half done... but it does shoot 1/2" stefans with ridiculous accuracy. But it takes about 5 pumps of a bike pump to get there. Everyone is going to hate me for this... but it's basically an s-rifle without the niper.

It's at my house in a-town, but I'll see if I can get my brother to take some pics or something.

Anyway, the point of all this is to say that: ball valves = slow and innaccurate due to the amount of force required to open it (your whole arm must move), where as sprinkler valves = awesome fastness, but nearly impractical for nerf due to size.

If I had made my air chamber smaller, then this gun would have kicked awesome bootang... but I didn't, and now it kicks bootang, but not nerf. Only larger things. Like marbles.

And Mr. bowie, the piston valves... have you ever tried shrinking one without making a whole lot of custom parts? This isn't meant to be sarcastic or anything, I'm just wondering. So far, I've had troubles, both due to size AND the "seal-off" pressure crutial to getting the thing to close.

Ok. I'll try and get pics up at some point...

Copy!

[davidbowie]

About the piston valves, I have made a 1" valve that sealed perfectly, save a small imperfection in the sealing face (barrel wasn't perfectly squared off before gluing ). This valve was a perfect nerf size, due to a direct 1/2" barrel output. Sadly, a hole I was drilling to tap in a blowgun for the pilot went horribly wrong, and now I need another 1" street elbow. The piston was thrown together out of random things I had lying around.

sprinkler valves = awesome fastness, but nearly impractical for nerf due to size.

I'm currently experimenting with a 3/4" male threaded sprinkler valve. It's uber small: actually about the size of a ball valve. I just don't know if it can be modded, or even if it works. If anything cool comes out of it (this will be an over-under nerf/marble pistol), I will be sure to post it.

[KirbySaysHi]

I can't remember if I used a 1" or 3/4" sprinkler... I've seen both tapped for a blowgun, so I don't see why you should have any problems.

I'm REALLY interested in your results... and how you made that 1" homemade valve... do you have any pictures?

[Arcanis]

After using them in many potato cannons, and then launching darts from a few of the smaller-bore ones, it is now very obvious that sprinkler valves, while pneumatically modded and whatnot are for potato cannons, and ball valves / the like are for Nerf. I'm a member of spudtech.com (under the same username) and testing some of the valve types Clide posted I can tell that even minature versions of these types are too ahead of the curve for a homemade Nerf blaster. While I do agree that having a general knowledge of the principles and techniques used in these is a "good thing," I do not think that the power levels they work best with are those of Nerf's. Once again, it's good to know them but the usage here is best moved to Spudtech.com.

That doesn't mean that shooting vegetables several miles with a piston valve and a pneumatically actuated solenoid + 3" PVC airtank isn't fun.

Edited by Arcanis, 01 December 2005 - 05:58 PM.

[KirbySaysHi]

I definitely agree with the launching of vegetables...

The only reason I've tried using solinoids and such for nerf is because I hate building custom parts, and thus far, I haven't found an easily adaptable valve that can be used for a variety of applications (with the exception of the at2k). The at2k valve is still unwieldy though...

Lately, I've been trying to pack as much power into the smallest possible shell.... to no avail.

[Dr Nerf]

Dr. Nerf, that's a nice gun! The bolt action is well done, and an integrated onboard pump is a really nice addition. How is your valve built?

Thanks. The valve works in a similar manner to the piston setup. A "piston" is inserted into the pressure chamber area and seals against the PVC. When retracted, the piston opens the front end of the pressure chamber, allowing air to escape. Also when it is retracted, it seals against the back end of the pressure chamber which makes only the air in the pressure chamber escape. A simple trigger setup makes the gun really easy to use.

The pump actually was made incredibly quickly. It has a male threaded adapter to screw into the input end of the gun. The input is just a female adapter, that way I can have a dozen different ways to pressurize the gun if I wanted. The gun was actually designed to use a pressured backpack setup, which I never had had the time to build, so I build the pump instead.

[notorious oxide]

I find steal ball valves to be fairly easy to open. After purchasing one i spray ot with WD-40 and it just takes a flick of my finger to open it.

[DX-Robert]

If it isn't opening fast enough, you could take off the handle and grease it. I also spray painted one, but won't any longer because heavy use wears off the paint from the handle.

There is an easy way to make a normal trigger system on a homemade that already uses a ball valve. However, I'll have to do some tweaking so that it works with a Nerf homemade. You need a PVC tee attached to the beginning of your barrel, a thick rubber band, a metal rod, and some cut-out pieces of PVC for the trigger itself and the holding slot, which gets mounted below the pc. Simple, really, just annoying to assemble.

[davidbowie]

even so, a pneumatically actuated valve with a blowgun trigger will open faster. Just about any valve will seem instant to the human eye, but a small time differential makes a whole world of difference.

I think nerf can be made more powerful than it currently is. All that we need are good launchers and aerodynamic, slightly heavier stefans, and surprising distances will be attained.

Arcanis, if you think sprinkler valves are for spuds, with all due respect, I think you have it backwards. Ball valves are high-flow, low open time. Their only good use is for heavy projectiles in long barrels with high friction, unless you have a full-port piston valve on your hands, in which case they're obsolete (save fragile-projectile guns). Sprinkler valves have low flow, but lightning quick open time, capitalizing on the flow they do have, and putting air to better use during the time that a light, low-friction projectile in a short barrel will actually spend in the barrel.

The only problem I can think of with a sprinkler valve is that darts won't be stable at higher speeds. I should really just shoot some nerf darts with a sprinkler valve before I conjecture more.