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Airgun with eXplosive air-Release Valve

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Picture of Airgun with eXplosive air-Release Valve
Forget amateurish sprinkler valves. Look no further than this type of valve for making airguns or anything where you need the air released explosively. This is my own design inspired by the valve inside an airbrush.

This instructable shows you how to make what I call the XRV (explosive release valve), which can be attached to a bicycle pump. This in turn allows you to turn an ordinary blowgun or pea-shooter into something a bit more serious.

The video does a lot of explaining, but for more detail including how it works, see the next steps.



 
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Step 1: Materials and Tools

Picture of Materials and Tools
To make the XRV, you need a handful of easy-to-find components:

Materials

1. Flexible bike pump hose - comes with most bicycle pumps)
2. Brass or aluminium tubing (about 1-2mm) - available from hobby stores
3. O-Rings (tiny) - available from hardware stores
4. Small spring - also from hardware stores
5. Tiny screw that fits into the end of the 1-2mm tubing
6. Tiny nut or washer that fits onto the brass tubing (see video)

Tools

1. Hand drill & very small drill bit
2. Fine file
3. Blade
4. Precision screwdriver
5. Pliers or multi-grips (pictured)
6. Hand clamp
7. Superglue

Step 3: The valve shaft

Now you need to find a piece of brass or aluminium tubing that fits nicely inside the housing. It is absolutely necessary that this tube slides freely through the housing, while being a snug fit.

Step 4: Valve air flow

Picture of Valve air flow
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Air will explode through this small tube, but we need to drill tiny holes to allow this to happen.
With a tiny drill bit, carefully drill two or three small holes into the shaft.
File any rough edges smooth so the tube glides through the housing without sticking at all.
DanTDM2 months ago

Hurry up and buy this:

QUICK EXHAUST VALVE

wolfy_90057 months ago
http://i44.tinypic.com/w2na1k.jpg

The completed project. 5/32 tubing, JAMEC style quick release male connector with a 5/32 hole in the middle and suitably sized everything else. For the people who want a little more top end in their project. Good for 4mm BBs
wolfy_90057 months ago
I slightly messed up by screwing an ever-so-slightly larger nut into the end. I mean, it will still lock in but the clearance between the housing I'm using and the tube is already very slight. On the plus side it doesn't need super glue, but it will mean it needs some wet/dry on the outside to fix the clearance or a simple trigger to push it back into it's spot after firing.
wolfy_90057 months ago
Go to any good hobby store and they will have the small tubes. Brass, copper, aluminium. 1, 2, 3, 4, 5, 6, 7mm brass, equal for the others. 305mm lengths, but they sell imperial sizes(1/16th, 1/8th, etc). Depends what you want I guess. If you want to experiment with the same size, just buy a 1m/36" length of the tube and have at it.

I ended up with 5mm(4.97~4.99mm) because darts like the extra air, however the connections to the air supply will be the hard bit. I managed to find a strong spring and the right sized screw in my box of bits, so now making a housing will be tricky. If you order something, make sure it is slightly small than required and either use a small file to make it bigger by the require amount, use some wet/dry on the shaft, or use some valve lapping compound and slide the two bits together to make the fit perfect. The better the fit, the less air escapes, and the more pressure you can put into the tube to shoot whatever you're shooting out the end.

420 O-rings on ebay of various sizes for $15.50

Anyway my thoughts on making this for a semi-auto;

1. Use thick walled tubing, you'll want to run a large amount of pressure behind the valve(3-400psi perhaps)
2. Use a strong spring. Remember, a trigger provides some mechanical advantage, so if you can barely compress the spring because of it's stiffness, then just modify the trigger to suit.
3. You need a way for the valve to release when the trigger is pulled and return whilst the trigger is still depressed, so you don't drain the reservoir or fill the barrel with BB's

Everything else will be simple enough. A paintball tank for the air, the valves/regulators will be the same as from the paintball gun, but the gun itself is expensive to import to countries like Aus(permits, fees, licences, blah blah).

Of course for a single shot this isn't a problem, just remember to take your finger off the trigger. Also be careful with paintball tanks, some are good for 5000PSI(average 3000psi), so you'll definitely need a regulator to get the right amount of pressure. Otherwise, a copper tube with ends brazed on and a schrader valve(like from a bike tyre) will probably work for a few shots so you don't have to keep pumping.

Just some thoughts
Some extra information;

I've been looking at making a slightly larger one using off the shelf parts. Anyway, I found a quick release connector(the male bit). It has threads on the inside, with a 5/32 hole in the middle. You can easily get 5/32 brass tubing, and it is a nice size to work with due to the weaknesses of tiny drill bits(plus the tollerances are tight,. The upside of using premade connectors like this is that there is usually a barb fitting with the opposite threads and it all screws together(just get some teflon tape). 10mm hose connected to a tank to hold some pressure and you're in business.

4-500psi may be safe through this depending on the wall thickness of the tubing used, the seal in the fitting and the tube, the tube construction(extruded or drawn), etc
Clonedone11 months ago
For y'all who be wondering where this guy got the little tubes, wonder no more!
http://www.amazon.com/gp/product/B000BRHE4M?ie=UTF8&force-full-site=1&ref_=aw_bottom_links
A
Took me forever to find. Enjoy!
cbass22721 year ago
What about water? How would this do shooting a stream of water?
milamber2 years ago
i machined a much larger version of this for my air rifle would anyone like to see a slideshow or ible??? credit to chluaid
of course
I'd like to see it myself I'm at
p a ll a d i n 9 8 0 0 0 at g m a i l period c o m
I'm an old dude living in Mexico building slingshots and crossbows a la J sprave for fun and profit
I would love to see what you have

huguesb.1968@gmail.com
yeh a slideshow would be nice.
PLZ RESPOND can a larger version be created with this design obviously stronger materials though. and i was wondering if instead of a bike pumb could i use a co2 cartridge. the cartridge wont be hook up directly to your device but will instead be put on a reservoir with a shut of valve and all that good stuff. btw never made a air gun but know how and what to make a gun the shoots 5 canadian quarters attached together. hopefully somewhere around 700+fps. something that will put a hole through a wall and another wall and so on. by the way AWESOME DESIGN
tinker2342 years ago
could i modify this gun to be automatic http://www.amazon.com/Crosman-1377C-PC77-Black-pistol/dp/B006QVTBVG/ref=pd_sim_hi_85 to shoot darts
pyrotech254 years ago
I have been looking for this video for years. im making an automatic bb gun (pistol) and this is perfect for the trigger. thanks a lot man!
if you make the automatic bb gun please post it on instructables because i have been also trying to make one...the hard part is making it automatic
Got to start by saying thank you for this instructable the best I've seen so far.

I haven't settles on what I will build yet, BBMG or single shoot, but one thing is for sure I will be using your valve ins some fashion.

for you gents that are looking for an automatic simple design I found the following a while back and it seems to be a nice fit for this valve.

automatic BB gun
http://www.swanstrom.net/petes/shoot/autobb.htm

Have fun and stay safe...!
autobb00.gif
TimmyMiller2 years ago
how big of a pellet can this shoot?
TimmyMiller2 years ago
where did u get the hand drill?
i really,really,really, REALLY WANT ONE!!!
pdub772 years ago
This is a wonderful design and your video was awesome as well! Good job!
sabladask3 years ago
i want all the tubes in step 3.....
where did you get them?
sabladask3 years ago
finaly!! i found somone who actualy knows what hes doing,.'
Grate woork!
i made a simulare gun som years back:) i have made very many air guns, and the valve you made is very good :):)
see my channel i if you are intrested in a springpowerd airpistion gun.
keep up the good woork!
ostomesto3 years ago
hey im planning to make this but dont have the bike tube for it. could i use a ball inflation needle to do the same thing as it. i lost my old bike tub and hope this will work
why dont you just go out and buy the tube then there probly no more then 5 bucks?
i didnt know where to find them. but i got it. I made one well not really. I made one that is a trigger for my spudgun, it's the pilot on my sprinkler valve.it about 5 in long and never leaks air. It has a huge airflow too. I will post a pic of it and how to build it if you want me to
ahahahahaha i found my old tube. it was in my air compressor parts box. i looked in there hundreds of times and it was right in front of me. hahahhaha im so happy :)
one last thing. i made this and it worked great. i am going to try to make a larger scale one for a trigger on my sprinkler valve in my spud gun. any ideas on what materials i would need to make a larger scale one. oh and would a large scale one hold around 60-70 psi maybe 80
Happy late christmas. http://nerfhaven.com/forums/index.php?showtopic=19073
Cheeseduck3 years ago
Rather than going through the hassle of hand-drilling, you could just use the small round hand file to make the holes. If you file perpendicular to the pipe, it'll make a good path for the air to escape.
wellbankj3 years ago
Do you have any idea how much pressure you think this little valve can take? I'm thinking of making a gobstopper gun that I can kill squirrels with and I'd like to maximize my energy output. I'm thinking of using a compressed air or CO2 tank as a power source and a regulator to tone down the pressure that's behind the valve.
freerunnin13 years ago
i'm going to make one of these tomorrow and im using a piece of pipe from a telescopic antenna :P, they come in loads of different sizes
ya antenna works great. just take out each pipe form it and u have lots of choices. it is a can bend and is a little flimsy though :(
freerunnin13 years ago
great vid! lol, how long did it take you to come up with the valve? oh and how many pumps would it take to propel a bb over say, 75 foot?
moGuyver3 years ago
Excellent animation in the video - also great valve design.
quirxi3 years ago
Cool vid - you should go to the film industry ! :)
Topunisher3 years ago
Can the hose(on the pumping stick) take on the pressurized air with-out getting it explode?
Fredock3 years ago
nice vid
milamber3 years ago
no chance youd make my life easy and sell me one would u ?
EnigmaMax3 years ago
Suspension pumps are not cheap! Would an tire pump suffice?
brum3 years ago
It think adapted with a harmer or something like that with a reasonable pvc tank or something and you might have yourself a multi-shot bb gun. You could potentially up size into a paint ball gun (uses almost the same principal)
Mattrox5 years ago
this is very cool for a blowgun or dart gun but sprinkler valves are used for their quick release of air which this wont let out enough air fast enough unless you supersize it. no offense intended very cool design by the way
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