Air Trigger - 1 -

   In November of 2002 I decided to develop an air cannon using a washing machine valve as the trigger and went on a quest to find a more secure method of sending the air in. What I found makes a $1 water valve as simple to use to trigger air as any $65 professional pneumatic solenoid. Here are the details.

 Of course you will need a water valve from a washing machine and not just any valve will hold the air back and reseat itself under the rather high pressure I would need for an air cannon. I wound up testing many, many different valves to see which work and which don't. There are two that I have had success with at high pressure such as what my Aerial Executioner operates at, some 85 lbs. Shown above is Horton C539 / n-6042 which not only worked well, but actually have larger inner porting, so the sound it produced for the cannon was slightly superior to the rest. The other valve that worked well as the N-51 as shown here. The first one (translucent white) is very difficult to find, but the N-51 is readily available at any appliance repair shop used or even from a scrap yard that recycles old washing machines for the scrap metal. It will cost you about $3 from the repair shop or $1 from the scrap yard. Be CERTAIN you get the Horton or the N-51! There are lots of other valves out there that look identical to the blue one above, but they are N-50s and DO NOT WORK under high pressure. Look carefully before driving all the way home. 

Note;

I have received many emails saying that they couldn't find any of these over the phone calling repair places and parts desks. I need to mention here that this is a part that you will have to get in your car and go hunt down, due to it's low value / high pain in the butt ratio to the repair men. So here's my best tip; you will definitely be able to find these things if you go to the city landfill or scrap yard as mentioned above. Every time I go there I can pick up at least two or three or more. Things to take with you to the landfill; large channel lock pliers to get the old water lines off the valve, flat blade screw driver to undo the exit water line, crescent wrench to remove the valve from the washing machine, a rag to clean your hands with after and a plastic grocery bag to put the valves in. Simple. It only takes roughly 2 minutes to remove these and they are really easy to get at, so don't worry about it. 

   We have covered the attaining of the water valve so now it is time to get the rest of the goodies needed to make this funny looking doowhacky into something that releases the fear of God into your hapless TOTs.

(1) Female Hose to FIP Swivel fitting 3/4" x 1/2" = $3.97 (Home Depot)

(1) Hose end cap = $.53 (Home Depot)

(1) 1/2 to 1/4" Galvanized reducer bushing = $.76 (Home Depot)

(1) 1/4" IID male air coupler = $.49 (Harbor Freight)

(1) 6' Extension cord = $.77 (WalMart)

(2) 1/4" Female Quick Slide, 18 ga. crimp cord fittings $.09 ea = $.18 (Harbor Freight)

(1) Washing machine water valve = $3.00

Total = $9.70

   This is simple business. Spin your hose end cap on to the water inlet you will not be using and tighten with a large pair of pliers so it is more than just finger tight. The same for the hose swivel fitting to the chamber that you are using. Attach the air coupler to the reducer and the reducer to the swivel using Teflon plumber’s tape. You will need to bring power to the water valve as it runs on 110V, so chop the female end off your extension cord and clamp female quick slide fitting to the end of each of the two leads. Slip on to either lead on the solenoid that triggers your water valve and then cover each with heat-shrink tubing or electrical tape. It does not matter which power cord lead you send to which connector. Either way will work as long as you attach your air nipple to the corresponding cylinder .

   And here is how it will look when completed. The top of this photo got cut off, but you can see that 3/8" air hose slips perfectly over the outlet nipple for feeding the air to your prop. And that's it!

   Here is an old photo of the completed system (using the previous method of forcing the PVC pipe end caps on which were tapped with threads for the air fitting) put together for the Exorcist that illustrates well how this will be used. I attached the air line from the compressor to one end of an air regulator and attached the out directly to a threaded fitting going into the solenoid. The air out of the water valve is hose-clamped on for a positive fit. For opening the air way to your pneumatic event you will merely send power down the power cord. Once released the air travels to a three way connector that will split the air to the air cylinder as well as out to a muffler fitted at the end of about 5 feet of line. You can see there is an air valve to the muffler line because we will be dialing in the exact amount of bleed that allows our pneumatic prop to reset.