~$5 qev and 3way valve made from a nerf gun

[iknowmy3tables]

So I've been experimenting with my secretstrike nerf gun, and if you don't know what it is, it's a $4 pocket sized pneumatic nerf gun that looks like this

so just so happens that this little blaster uses a piston valve as it's main valve, and if you want to see the details I posted a thread on nerf haven with some self explanatory diagrams link

I so I realized that this could be turned into a qev, but in addition to that I realized that the pump could also be turned into a 3way pilot valve. I attached a 1/8" nipple to the side of the chamber so I could attach an extension to the chamber and I relocated the pump
so the basically I took this

and turned it into this


so I didn't initially think about doing a write up but part way though I decided I should take pictures as I went so other could try
so roughly sequential in the process

this first picture is from nerf haven internal directory Courtesy of Gengar003



if you cut enough off and maybe heat the plastic a little it should clip on just fine

make sure the hole is lined up and epoxy it in place, I added lots of puddy because I had to use super glue instead of liquid epoxy which sticks but doesn't seal

I initially intended to tap it and fit it with a 1/8" NPT hose barb but I only had a 1/4" hose barb

so I'm still testing with it but here's a video of the chamber and valve working at just 10psi
video
recently I've hot glued a short marker barrel and tested this thing at 20 psi with a marker tube barrel and shot some streamline nerf darts and this thing gets about ~50feet
(note: stock nerf guns get about 20 feet max)

[thedeathofall]

so basically you turned a $5 gun and $5 of parts into a semiautomatic nerf gun... ingenius. I applaud your effort, although I dont recomend you go beyond 10 or 15 psi... Cheap plastic is not forgiving!

[POLAND_SPUD]

hehe that's ingenious...

notice that it is unbalanced.. not that I think it's bad, in fact it has some advantages: at first it's difficult to pull the trigger as you've got to overcome pressure but once it starts venting pressure acts on the other side of it and forces the valve open

[iknowmy3tables]

well it gets plenty of power at just 20psi, but 10-15psi is rather low if you think about it think 40psi is tire pressures and I bet the pressures on a fully pressurized stock secret strike are around 10-15psi and they're probably built with a really high saftey factor,
I'll keep it low anyways it'll give me more shots, and even if it does blows up at such low pressures it's not likely to cause any serious injury

@poland spud: i hadn't thought of it that way, however the pressure from the input still imposes a lot on the trigger, but since I have a consistent regulated air supply all I have to do is wrap a few rubberbands on it to counter act the pressure and the trigger pull is lighter

EDIT: actually I've recently just heard that some nerf gun modders take their guns up to as high as 60-70psi and probably more if they have the pump to do it

[k9turrent]

EDIT: actually I've recently just heard that some nerf gun modders take their guns up to as high as 60-70psi and probably more if they have the pump to do it

Well for certain Nerf airtanks, 60psi is the highest safe level of pressure to use even though the air could go higher. But I do like innovation in this one.

[iknowmy3tables]

thanks for the background info, I'll keep it is mind with my future projects

[Mr.Sandman]

thanks for the background info, I'll keep it is mind with my future projects

Well judging from this i can loo forward to your projects. Are there any larger diagrams I think I might want to make one of these with aluminum tubing.

[iknowmy3tables]

thanks for the background info, I'll keep it is mind with my future projects

Well judging from this i can loo forward to your projects. Are there any larger diagrams I think I might want to make one of these with aluminum tubing.

yeah man the pictures are just click-able thumbnails , they're actually pretty big which is why I made them thumbnails links, you can also check out the link I gave to the other thread

I'm not sure if this would be the best design to build from scratch, the whole point was that it was made from an existing thing that was cheap, so just check out the diagrams and the link and you can make that call, also if you intend on using higher pressures you might want a balanced pilot valve

[Gun Freak]

I think the pressures you are using in that thing is fine for firing nerf darts... I found that the best pressure for firing nerf darts was about 35-40 psi for them to fly straight and faster than they did at 100 psi.