Now very hesitant to ask for suggestions... :P

[Asuka Jr.]

I've been looking around at some of the posts, and considering what I'm seeing I'm rather hesitant to reveal what I want to do, and ask for suggestions/ideas... sigh.

I'll just dive right in... and if I get laughed out, I'll know I came to the wrong place:
I'm not trying to achieve hunting velocities, and certainly not trying to shoot through aluminum siding. I'm afraid I'm trying something extremely silly and very complicated. So much so that I have no idea where to start...

I have a deep and abiding love for the Nerf Maverick (yes, the foam dart gun). My only serious problem with it, is that it's a revolver, but has to be pumped (cocked) for each pull of the trigger. I want to put in some sort of internal pressure chamber (like permanently mounted CO2 cylinders with a nipple for re-charging) and adjust the internals for more accurate ratcheting/chamber alignment to convert it to a true revolver style gun.

While I intend to eventually make some with brass barrels (for the look, as well as smooth bore), I'm still only looking to fire foam darts (probably home-made 'Stephans'), so I don't need 300-400 pound launch pressures. I'm going to be dealing with a very limited storage volume, so I need to maximize efficiency so far as minimal volume consumed per shot (6 shots to the full gun load).

So the question is: How do I even begin trying to work out how the actual pressure regulation/delivery system should be made? I think I can manage the mechanicals of how to more accurately control barrel stop/alignment for consistent fire, but I'm completely at a loss as to how to deliver a measured (and controlled pressure) burst of air in time with a simple trigger pull... (T_T) ...basically I want it to work like an actual revolver: one pull of the trigger, one shot fired.

Any ideas, suggestions, possible other places to go if the community here has no interest in 'mere toys', etc., would be greatly appreciated. I'd really like to get started on at least a prototype, but without any idea of how to build a pressurized air gun, I'm against a wall...

Thanks for indulging my rambling explanation, and taking the time to consider my post. Hoping to hear something soon...

Asuka Jr.

[Pellethuntr]

it is deff possible to achieve what you want...it will depend on 2 things...#1 how much you are willing to spend on such a project and #2 what tools you have access to...do you have access to machining tools such as a lathe and a mill???

[Forum Admin]

I've got one of those too. My son and i love shooting eachother with it. Lol i'm at work right now i'll take a look at it later. In the mean time there are a couple of nerf forums out there as well that have some cool mods

[username1]

Nerfhaven.com?

[mouz]

um, i have no idea how a nerf gun works.... is it spring piston? if so it is possible that you could somehow make it cock the spring with the first part of the trigger pull and fire it with the final 1/4 inch or so, and have the action of the trigger moving forward spin the chamber. the only issue with this is the ten pound trigger pull your gonna have. but thats totally out if its not spring piston. if its single stroke( you pump it once to charge the chamber) its possible you could hook up a motor to it that would push the pump in and have a spring pull it back out( hey this is actually a really good idea! you could even have it multiple stroke and have the motor push the pump in and out many times) and that would work beautifully. but i would suggest moving to rubber band guns( not the store bought pieces of **** there way to low powered, you want at least 13 inches of band stretch) you can make the best of semi auto and fully auto at home with some plywood and a band saw.

[Asuka Jr.]

@Pellethuntr: well, I'm an aerospace machinist with full access to the machines and mostly free use of (reasonable amounts) of scrap material for free, so ya, I have access to both lathes (as well as an experienced lathe operator usually willing to do small piecework for me just for the fun of it... (^_^) ...and as for money, I'll certainly be trying to minimize cost as much as possible, but the primary goal is the functional pistol, so I'm in for what it takes... hopefully less than $100...

@Forum Admin & username1: Yeah, there are some really nice mods (I've already done the Russian Roulette mod, and replaced all the barrels with CPVC tube), but if you surf those types of sites, so far I have found NO ONE who has actually made a Maverick into a fully functional, air powered revolver (with the whole semi-auto action), except a video on YouTube of a guy attaching an air-hose to his modded Maverick and rapid-firing through all 6 rounds... but as that video had no sound, I know that all he did was straight-pipe an airline through the gun such that each dart would fire the moment it aligned with the air stream. Not what I'm trying to do. (I count that one as a cheap cheat)

@mouz: Yes, it is a spring piston, but the point here is that I really wanna have it be smooth, easy pull, air pop sound, clean shot... and yeah, a 10lb pull is definitely excessive. If I'm understanding your recommendation for rubber band guns, you're missing the point altogether. If you'll look up the Maverick, it has a distinctive look, and I want to preserve it. As well, if the pressure is able to be regulated, soft foam darts are far less painful than rubberbands. (I'll assume you were being serious, rather than mocking) If you go to http://directthreat.blogspot.com/2006/10/on-proper-opening-and-modding-of-nerf.html, you'll see the inner workings of the Maverick.

Thanks everyone for your willingness to reply to my post, and I hope to hear more from folks. And really, if the greater majority of users here feel this is an inappropriate project for this site, please let me know. I came here specifically because I need the knowledge of people experienced with air burst delivery, and who better than people that make air guns?

Thanks again, till next time!

Asuka Jr.

[mouz]

i know rubber bands hurt. thats why i use them, someone can't just claim you missed, because it hurts. i now have looked up this maverick Nerf gun and i see that you want to keep it the same visually, so i think the way to do it would be an electric solenoid vale that opened for a tiny fraction of a second when you pull the trigger, and had some sort of air blow back system to turn the cylinder. how hard is the cocking lever to pull back? if you had it fired by air rather than a spring it might travel faster and farther, depending on how much air you shoot it with and how much pressure and also how strong the spring is.

[Asuka Jr.]

The cocking spring is fairly strong, there have been complaints from some people (mostly women) about how much strength it takes to cock the gun. I don't have a pull scale, so don't know exactly how strong it is, but the normal adult does not have much difficulty pulling it back. (mostly frail ladies, or concerns about children being able to pull it. As it's scale is far more suited to older children and adults, it shouldn't be an issue)

The main reasons I want to fully convert to air power, are for rate of fire, (hopefully) increased range, and the simple shock value of being able to unload on someone without having to cock the gun, or having undue noises come from the internals.

Am I wanting too much, or do you think it's doable?

Thanks again for posting. (^_^)

[Forum Admin]

I can vouch for the strong spring, I have to cock it for my almost 3 year old son to chase me around the house and try to shoot me with it.  I think it is very doable, possibly using a modified solenoid valve from a dishwasher would be the easiest way to do it. Here's one that would work, just take a bit of modification: http://www.appliancezone.com/ShowProduct.aspx?ID=5956. Remove the brackets to trim it down. Some threaded barb fittings will allow you to connect it to a airsupply with those clear flexible vinyl tubes. Contrary to what the specs might say, a 9v battery will actuate valves like that. A momentary switch hooked up to your trigger will fire the valve. Hook it to a airtank made from PVC pipe and you should be able to get plenty of shots per fill.
Let me know if I can help you, like I said I've got one as well, so I dont mind tearing it down to give you some ideas and possibly convert my own.

[Asuka Jr.]

I would definitely welcome any assistance you can give, as I really want to do this right, so better too many suggestions than not enough. I have a long-ish reply that the system (or an issue on my end) will not currently allow me to post, but I'm wondering just how finely it is possible to control pressure and volume of air delivered to the firing chamber... As soon as I figure out how to post my original reply, I'll get it in.

Thanks again for being willing to consider my project and possible directions to try...

[Forum Admin]

Try doing your long post in two sections. I'm not sure if there is a character limitation on this forum software I use, I'd be interested in seeing if there is. Looking forward to seeing this project take shape. 

[Asuka Jr.]

I was just about to do so, when the system told me there was a new post... yours, recommending I do so:
I looked at the valve, and being the complete tyro on these things, I have no idea what size it is, or how much pressure it can 'hold back'. As I had said in an earlier post, I work in a machine shop, and was hoping to do more of the construction in metal, and to be able to run serious compressed air volume for maximum shots per re-pressurization.

How much pressure can this kind of valve withstand, and is there some way to... I don't know, have a secondary chamber to step the originating pressure down and limit the direct flow, while ensuring I'm not blowing too much pressure into the firing chamber? I know most people here are shooting (no pun intended) for as much pressure and power to the barrel as possible, while I'm just the opposite, I want to finely control the power and volume of air releasing to the firing chamber... Am I hoping for too much, or can it actually be done?

I've looked into the firing systems of paintball guns, and was even fortunate enough to have someone give me a couple of older guns to pull apart to see if I could use a similar mechanism, but I'm convinced that (much like your idea) something like this can be much simpler. But I've also read about the problems with controlling the pressure of the pre-firing chamber when the pressure in the CO2 bottle gets too low (as the pressure valve is spring loaded, and when the pressure behind it is no longer enough to properly seal the valve, it can leak, allowing the still higher than desired pressure to build the pre-fire pressure above set limits).

Are there pressure valves that can control the pressure consistently, allowing the use of a pre-firing chamber to store the desired pressure and volume of air to be delivered to the chamber, while preventing the pressure bleed up described above? Or am I just wanting too much?

Thanks for replying to my posts so far, and I look forward to your further replies... (^_^)

(I found the posting problem: a retarded router. As soon as I disconnected my Linksys router from my network, I had no further problems posting, or editing. Gonna have to figure out what went wrong... )

[boar]

i think this sounds like a fun project im not sure how much room you have inside that gun but tha kids have both been wanting 1 so i may go get 3 this next weekend. I think with 2 small silenoid valves with a small tank between then a regulater and a larger tank  would take care of the air problem and could be adjustable night need a small circut to open and close the first valve some where during the first part of the trigger pull then hit another switch at the end
or maybe open and close the fill valve on trigger release I think the hard part will be trying to make all this fit in the gun maybe there are some real small silenoid valves out there that could be used i dont think its going to take real high pressure to get what you want. if you could measure the dia of the cylinder and the length of the srtoke we could get an idea of the volume required and if you could measure the strength of the spring we could come pretty close to the pressure required to make it fire like it does now then we just boost those up a bit.

hope there is something in there you can use and let us know how it goes
Boar

[Asuka Jr.]

Ok... Sorry all for the long time between posts... They've had me working 12hr shifts at work, and time to get online has been at kinda a premium.

I'm not at all familiar with solenoid valves (but I would assume the one linked by Forum Admin would be one), so have no idea how big they are... I like the idea of having a couple of momentary switches on the trigger, I think the best would be to have the one that fills the chamber be just a little before the firing switch. This way you wouldn't end up with a pre-fire chamber that could be leaking pressure between shots, if you're not so inclined to rapid fire them. Since the momentary switches can be quite small (so far as I know), the only real space stealing objects would be the primary pressure cylinder, the pre-fire chamber and the solenoid valves. Does anyone know of any particularly small ones that can handle pressure?

The only reason I want high pressure capability is to maximize gas volume to maximize number of shots per recharge, not to try to push the dart ultra fast. I mean the volume of air currently being utilized is from a cylinder with .8" id, and a total stroke length of 1.85". It's one tube (with an o-ring for a seal) inside the .8" id chamber and the larger chamber is pushed by the spring onto the smaller one. The smaller tube has an opening (for air release and draw) approx. .46" wide by .25 high. There is a mod out there that claims to increase range (not by much, but a couple of feet is a couple of feet) where you place a straw (say from McDonalds') into the smaller cylinder sticking out of the delivery hole, as well as centered in the wide end. You then fill the remaining space with filler foam (the two-part stuff from hobby craft). It's intended to remove the cushion effect of the unused air volume in the smaller cylinder, thus increasing the pressure and flow of the actual air being moved.

As for space inside, there ARE ways to increase available space, as I intend to permanently affix the slider to the gun, the layer of plastic under it can be cut away to open some extra space inside. If you find a some pictures of the inside of the gun online (like the ones I posted a link to above) you can scale the image by understanding that the opening for the barrel is 4.35" at it's widest (where the barrel hinges slide) and is 2.6" from top to bottom. The entire gun is approximately 11" long (if you don't count the back slope of the grip).

So the questions are where do I need to look to find (hopefully) small solenoid valves, and how do I regulate the pressure that builds in the pre-fire chamber?

Thanks for all the replies, and I'm starting to get an idea of how this will work, but I still have to fill in the blanks... (T_T)

[Forum Admin]

Here's probably the best way to control pressure: http://www.palmer-pursuit.com/online-catalog/stabilizer.htm. You can feed the gun with a standard CO2 of HPA tank and remote line, the same stuff used for paintball markers. You can put the tank in a backpack or wear it on a belt.

It is hard to find a reasonably priced solenoid valve that is small, Here is another possible option: http://www.mcmaster.com/#pneumatic-toggle-valves/=7wwlaa. These seem compact and easy to interface with a mechanical trigger. You might be able to go to a appliance repair shop and look at a dishwasher soleoid valve and see if you can make it work by removing brackets as well.