So it doesn’t snow enough where you live? Fear not — if it gets cold, you can cover that front lawn in white, fluffy snow with your own homemade snow gun. All you need are a few items from your local hardware store, some quality spray nozzles, and access to a pressure washer and an air compressor.
This snow gun is based on an internal-mixing “combo” design I found at http://snowguns.com. It mixes pressurized air and water internally and sprays them out through 2 types of nozzles that work together cleverly. Just wrap teflon plumber’s tape on all the pipe threads, then twist it together tightly as you see it in the diagram.
To understand how it works, remember high school chemistry: the smaller a particle is, the more surface area it has relative to its volume. Generally, that makes it easier to freeze. This is the job of the nucleation nozzle; it breaks the water into very small particles, making it possible for them to “nucleate,” or freeze quickly around their own impurities, thus generating a spray of superfine ice crystals.
This “ice mist” then crosses the spray from the 2 bulk nozzles, which supply the bulk of the water for our snowmaking. Droplets from the bulk spray freeze to the nucleated ice crystals, creating fluffy snow.
Steps
Step #1: Get some nozzle knowledge.
Next
- Nozzles are the most important purchase for your snow gun. To make an effective snow gun you have to match the bulk nozzles to the nucleation nozzles, and match both to the characteristics of your compressor and pressure washer.
- A good brand is TeeJet; they make spray nozzles for agricultural use and these work great for snow guns. TeeJet nozzles are numbered by their output; on their face is a 4 or 5 digit number whose first 2–3 digits represent spray angle, and whose last 2 represent flow at 40 pounds per square inch (psi), measured in gallons per hour (gph). For example, nozzle 8005 translates to an 80° spray angle and 0.5gph flow at 40psi.
- The trick to matching your bulk nozzles to your nucleation nozzles is that the nucleation spray must engulf the bulk spray, or else the bulk spray will have wet edges (spraying non-snow, just water). But you don’t want the nuc spray overly wide, or you’ll lose efficiency.
- Here are some good angles to use: 40° bulk and 65° nucleation, or 50° bulk and 80° nuc. (I used 65°/80° here because that’s what was in stock.)
- The photo shows a list of nozzle volumes (gpm) at various pressures (psi).
Conclusion
Output and Precautions
So I’m sure you’re wondering, “How much snow can I actually make with this thing?” The answer depends on how much water you’re flowing, and this depends on the water pressure and air pressure. The more water you’re able to flow through the gun, the more snow you’ll have piling up. Expect 2"–5" per hour, at 2gpm flow. Some advice to keep in mind:
- Don’t shoot snow against the wind. You’ll get freeze-ups. Go with the wind to make life easier.
- Install a check valve between your compressor and the snow gun; this will prevent flooding of your compressor.
- Air compressors are loud, so if you plan to make snow overnight or in the early morning, be considerate of neighbors.
- Your snow gun will hiss like a gas leak, so inform your neighbors that it’s nothing to be afraid of.
- Wear plenty of warm clothing when you’re making snow, because it will be cold outside, and when you’re working with water and metal pipe it will seem a lot colder. Wear good waterproof gloves.
- Don’t leave your hose outside with water in it, or it will freeze and possibly split. Bring it inside. If it does freeze, throw it in a bathtub of warm water.
- Last but not least, have fun!
Special thanks to the contributors to snowguns.com, where much of this information came from. All images, except Step 4, courtesy of James Moss of makesnow.com
This project first appeared in MAKE Volume 21, page 125.
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What do you mean? Are you asking what you can use this for? If the weather is cold enough, you can make your own white Christmas!