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Step 3: Modding The Sprinkler Valve

Here I will teach you how to modify the sprinkler valve for pneumatic actuation.

You should find all the materials at Home Depot.
You'll need a:
1" sprinkler valve
1/4" brass nipple
1/4" blow gun
Epoxy
Teflon tape

Step 1:
Take all the screws out of the lid from the sprinkler valve and then pull the lid off. Leave the rubber diaphragm in place and make sure you don't lose the spring.

Step 2:
Get a drill bit that is slightly small in diameter then the brass nipple and drill a perfect hole in the middle of the lid from the sprinkler valve. Put some teflon tape on the brass fitting and thread your blow gun on, make sure to remove the nozzle from the other end if it has one.

Step 3:Thread the blowgun with the brass nipple into the hole, make sure to do it slowly and perfectly straight. Remove the solenoid (big black thingy) from the sprinkler valve. Mix a small amount of epoxy and clog up the hole where you just unthreaded the solenoid from.

Step 4:
That's it, just leave it to dry.

The sprinkler valve will be used as the pilot valve for the piston. You could get away with a 1/2" ball valve instead but this will give you more power. Any problems with the valve, read this:
http://www.spudfiles.com/forums/viewtopic,p,95154.html#95154
Ok great instructable. I hope you got an A or equivalent. Time for me to build one.
<p>where can I get the piston valve from? and how much is that?</p><p>thanks</p>
<p>I need to make a device to shoot a plastic golf ball. What would you recommend for clearance on the inside diameter of the barrel to ensure a good fit? I was wondering if I needed a full 1/4&quot; or if I could get away with 1/8&quot;.</p>
<p>Great instructable! Quick question, what do you think would be the easiest way to modify this to make it shoot tennis balls? I would assume switching the barrel but with your breech loading not sure how to go about doing that.... Thx</p>
<p>nvm just figured it out haha</p>
<p>another question......if I want to make it a muzzle loaded cannon, can I get a way with not buying:</p><p>2 x 50mm pressure rated PVC male threaded spigot fitting (2&quot;)</p><p>1 x 50mm pressure rated PVC coupler (2&quot;)<br>1 x 40mm pressure rated PVC coupler (1.5&quot;)</p>
<p>when you say &quot;The sprinkler valve will be used as the pilot valve for the piston. You could get away with a 1/2&quot; ball valve instead but this will give you more power.&quot;....I don't understand, you have both on your cannon in all of the pictures of the finished cannon...could you make sense of this for me....which do I use, or do I use both of them.?????</p>
The ball valve (on the left) is only 1/4&quot; and is used to control the filling of the cannon with pressure. You connect the pump, open the 1/4&quot; valve, fill the cannon, close the valve, disconnect the pump.<br><br>The sprinkler valve on the right is 1&quot; and is the pilot valve.
<p>but could I use both as it is shown, just to keep accuracy and consistency? and can you please reply to my first comment about changing the size since I am trying to make it shoot baseballs and tennis balls</p>
<p>I don't understand what you mean, neither valve has anything directly to do with accuracy. Build it as shown, use the SPRINKLER VALVE to FIRE the gun, use the BALL VALVE to OPEN/CLOSE the quick connect fitting.</p><p>If you don't want to use the sprinkler valve, replace it with a 1/2&quot; ball valve. The 1/2&quot; ball valve already on the cannon is not suitable because the brass quick connect fitting drastically limits flow.</p><p>Yeah you just have to change the barrel. You could make the tee fitting/valve larger but this guide won't be able to help you much with that. The tee fitting has a 2&quot; threaded female adapter, just get a 2.5&quot; barrel (or whatever fits baseballs/tennis balls) and add a 2&quot; threaded male adapter to the end.</p>
<p>I didn't mean accuracy with the shooting aspect of it, I was talking about the accuracy of constructing it in relation to yours, that's all</p>
Sorry, you're right that the ball valve on the left is 1/2&quot; (I later replaced it with a 1/4&quot; one). Anyway, the quick connect fitting (the gold brass fitting on the end) is only about 6mm in diameter and would severely reduce the flow through the ball valve meaning it wouldn't be appropriate as a pilot valve.
<p>I'm making it for a school project. I need to change it from the size of a golf ball to the size of a baseball or tennis ball. Could I get away with just changing the barrel diameter to fit a baseball or tennis ball, and change the Tee fitting up towards the muzzle, and other necessary parts up towards the breech/ chamber.</p>
<p>If you can find a PVC like that unique galv. iron 3-way, let me know. I can't find many small threaded PVC fittings (elbows, tees, etc) here and I already had the iron fittings. Plus, they're in a somewhat structurally important area where there is some leverage on the fittings when being held at the valve.</p>
<p>Doesn't look like they ship overseas and there's a minimum order of $25. </p><p> I would consider making the pilot area out of HDPE over PVC. In fact, I believe the 50mm x 25mm bushing is HDPE if I recall correctly. HDPE would be much better suited for the pilot area because it is less brittle than PVC. It's relatively easy to snap the threads on small diameter PVC fittings and I couldn't risk that in an area that will be under a fair amount of stress during firing.</p>
<p>hi can I buy all they's parts at home depot in America and how do u do the conversion</p>
Not sure if this is still open. <br>When the piston is retracted what gap should there be from the back of the piston to the barrel, I am thinking 8 mm is this enough.?
ok i am extremely confused...why is it that your pumping air into the valve and the piston area? shouldnt you be pumping air into the chamber? and why is one of the openings to the sprinkler valve not attached to anything? sorry for all the questions im just confused
1) You need air behind the piston to force the piston against the barrel. Once that happens, air moves around the piston and fills the chamber.<br>2) Because it vents the air from the pilot out in to the atmosphere
ohh ok i get it...but why would i do this if i could just make a cannon that goes <br>chamber-ball valve-barrel<br>and just release the ball valve to fire?
yes but a piston valve is significantly faster at opening than a ball valve getting a very noticeable in force and distance
This is a crude, first draft I came up with that might work. Im going to do further designs in 3D to see how it looks with correct specs for actual use in a potato gun.
Gosh, that's LETHAL!
u a kiwi? same here<br>
Yeah mate.<br><br>You made any cannons or such? Where abouts do you live? I'm in Auckland myself.
yea i made a potatoe cannon and ended up with no eybrows, yea im from dunedin, i found a guy from chch too. i made a mini cap gun and modded out with a peizo clicker and redbull shot! BOOM NO EYElashes, dont put lighter fuel in a cannon then look down teh barrel!!!!!!
i did the exact same thing (no eyebrows) like 2 years ago and people still talk about it!! good times lol
It sucks ahe! Mine got kinda glued together, mum threw the gun out cos she suqs it was a weapon cabable of harm, my little finger!
haha nice yes that too my eyelashes melted together so opening my eyes was sticky...my mom didnt find out until like a year later lol
now dats a hole puncher!
I'm American, and I can't seem to find any of the 1.5&quot; SDR 21 PVC on any website or store. The site you linked is broken and my antivirus software blocks a trojan whenever I go to that URL. Can you help?<br>much thanks,<br>-Frag
Nevermind, SpudTech.com has it.<br><br>Great tutorial, BTW
hi, would someone make me a golf ball cannon? i would like to have one to get rid of wild critters around my house. how much would it cost me. thank you
Just wondering where you got your pressure gauge from?
I'm going to post a vid on how to do this b/c it seems a lot of people have issues. (Actually I already made it, I just didn't post it.) Also Sprinkler Valves are only meant to go to 90 PSI. Well, at least, mine says that on the box. Lastly, do you have any problems with threaded parts? I wrapped mine in 4 layers of teflon tape and it still leaks. I heard that you should use gas teflon tape, but i'm using the regular ones that come in a blue thing.
Mine says 125PSI but it doesn't matter anyway, they're probably good to 200PSI. Blowguns are only rated for 90PSI but can be good to 700PSI. <br> <br>I only have problems with brass threaded fittings, just wrap them in more layers and insure the threads are clean. The gas teflon is just normal stuff but thicker pretty much.
Oh whoops. You're right! I meant that my blowguns are only rated at 90 PSI. Also should I get gas teflon tape? It's sort of expensive considering that regular teflon is 30 cents and gas teflon is $3.50
You can buy a pipe cleaner liquid instead of using mthylated spirits
Using this design, would I be able to consistently shoot a golfball around 30 m/s? I need to design one, but don't require much power, just consistency around 30 m/s. Do you have any suggestions?
Only 30m/s? May as well just use a 1&quot; sprinkler valve (the pilot valve from this cannon). <br> <br>Would make things more consistant than a averagely constructed piston valve. <br>Easier to build, cheap, easier to maintain. Go with a 1&quot; sprinkler valve in my opinion.
WOAH! Maybe you should make a list for Americans and a list for other people (aka metric and not metric).
Problem with that is 40mm PN12 PVC pipe in NZ will fit a golfball, the American equivalent (1 1/2&quot; Sch40 NSF-PW PVC) wont fit a golfball, you need 1 1/2&quot; Class 200 PVC/SDR-21 which can be hard to find. Apart from that, all measurements are convertable pretty much, only takes someone two seconds in google to find out (or if they're like me, they will know both measurement systems). Thanks.
Yo crowley, Is there a equivalent of the 40mm PN12 PVC in metal pipe (steel or SS Preferred). I am in NZ also.
Probably, but not that I know of. I know there is in America, think it is 1.5&quot; Sch40 Aluminium. Just bring a golf ball with you if you can and have a look around
Hey again,<br><br>I have found out that the closest I could get in metal piping is 5shedule, ID = 44.98mm and 10shedule=42.76mm<br>For reference, do you have any idea the ID of the 1.5&quot; SDR 21 PVC you used on this cannon? Then I will be able to determine which will be the better fit. <br><br>Thanks<br><br>
I didn't use 1.5&quot; SDR 21 PVC, I used pipe from my country (i'm not in America). If I recally correctly, my barrel is about 43.2mm in diameter, most golfballs will fit this perfectly. There are a few golfballs which are too big for it. I think golfballs have to have a minimum diameter of around 42.67mm, so that 42.76mm pipe might work, it might not.
gooday ive heard of someone shooting batteries out of something like this,the large ones that go in radios, maybe this can give you more scope for using diffrent size tubes

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Bio: I love building things that shoot other things whether they be small plastic BBs or 135g steel ball bearings. If you need help with a ... More »
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