Home Snowmaker / Snowgun - Internal Mix




Hey everyone, this is my second instructable I think the big thing I learned from the last one is:


If you do that I'm sure we'll get along famously. 

This is an internal mix snowgun, meaning that the air and water mix inside the plumbing.  Because they mix inside the plumbing there is a risk that the air may back up the water, or that the water will back into the air lines.  I recommend using check valves on both the air and the water lines (not shown) in order to limit this risk. 

The author, instructables.com, and any supplier mentioned in this instructable is not liable for any damage or injury that result from following these instructions.  Please know that with all do it yourself projects there are inherent risks which may or may not be foreseen, and that precautions to protect yourself should be taken throughout construction and operation of the snowgun.  You will be working with high pressure water and pressurized air, both of which can be dangerous, please wear hearing and eye protection when you are using your snowmaker.

These plans are more detailed, but for a printable copy either print these plans online, or visit http://www.makesnow.net/FreeSnowmakerPlans.php for a selection of home snowmaking plans.

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Step 1: Parts List for the Home Snowgun

Here's the parts, it's a pretty comprehensive list.  You can however add to it or modify it if you feel you have a better design.  You will need a pressure washer and an air compressor for this snowgun to work.

Only use high pressure pipe fittings, using fittings not rated for high pressures may result in injury.

(3) 1/4" T fittings
(2) 1/4" Street Elbows (one side is male thread, one side is female thread)
(3) 1/4" Pipe nipples (male thread on both ends)
(2) 1/4" - 1/2" Bushings (1/4" female thread, 1/2" male thread)
(1) 1/2" gate valve
(2) 1/4" hoses (no longer than 10 feet) (www.princessauto.com)
(1) 22mm pressure washer fitting (we used a female one because we had hoses made up, you should use a male threaded one if you have a 22mm fitting on your pressure washer's hose)
(1) 1/4" air quick connect (female thread if you are using a hose, male thread if you are using your own hose)
(1) stand (needs to be at least 4 feet tall
(1) MSM0304 nozzle (available at www.makesnow.net)
(2) MSM0204 nozzles (available at www.makesnow.net)
(1) roll of teflon tape

(2) Pliers

Air Compressor:
Must be oil lubricated, and produce at least 5.5CFM at 40 psi

Pressure Washer:
Between 1.3gpm and 2.5gpm

Step 2: Step 1 - Teflon Tape

use plenty of teflon tape, this will make sure that your snowgun doesn't leak.  Every male thread will need at least (don't be too worried about using too much) 3 layers of teflon tape, feel free to go up to 6 layers for added protection from leaks (and it's cheap, like a dollar a roll)

TIP: Try and wrap the teflon tape the same way as when you screw in when you're attaching it, this way you wont get loose end that come up and peel it off when you attach your fittings.

Step 3: Step 2 - Attach Your Fittings to the Hoses

If you are not using hoses, ignore this step and just connect your adapters (the one for the pressure washer and the one for the air compressor where we say to attach the hoses with each of those adapters. 

Put the air quick connect on one hose, and the 22mm pressure washer adapter on the other hose. 

Reminder:  Teflon tape should be on these threads too!

Step 4: Step 3 - Build the Snowgun

So attach one of the street elbows to one of the T fittings on the top of the 'T' (see picture)   Brass is really soft, so be careful if you are using brass fittings not to overtighten, slightly tigher than hand tight is good.

Step 5: Step 3 - Build the Snowgun (2)

Now attach one of the nipples to the other side of the 'T' fitting from the last step.

Step 6: Step 3 - Build the Snowgun (3)

Now attach a T fitting to the hose with the pressure washer adapter on it.  (if you are using your own hoses this is where you would attach the pressure washer fitting directly to the T fitting).  

Then take that T fitting and connect one side of that T fitting's top to the nipple from the last step (see picture for final product)

Step 7: Step 3 - Build the Snowgun (4)

Now add another nipple to the open side of the T fitting from the last step.

Step 8: Step 3 - Build the Snowgun (5)

Now lets start a new section.  Start by attaching the air hose to the other street elbow.  And then connect that street elbow to a T fitting (see picture)

Step 9: Step 3 - Build the Snowgun (6)

Now attach a close nipple to the bottom of the T fitting from the last step (see picture)

Step 10: Step 3 - Build the Snowgun (7)

Now attach a bushing to the open nipple from the last step.

(picture coming soon)

Step 11: Step 3 - Build the Snowgun (8)

Now attach the other bushing to the other nipple from the part we finished with in step 7.

(picture coming soon)

Step 12: Step 3 - Build the Snowgun (8)

Cover the threads on the bushings with teflon tape and then attach the gate valve between the two bushings.

(picture coming soon)

Step 13: Step 3 - Build the Snowgun (9)

Now it's time to install the nozzles.  Install the two MSM0204 nozzles in the street elbow and T closest to the top.  Remember the Teflon tape on the nozzles as well.  Make sure that the nozzles are parallel to the ground, otherwise you'll be shooting the water at the ground before it gets to freeze. 

Install the MSM0304 nozzle opposite the air hose in the T fitting at the bottom.  Again make sure that it's spray is parallel to the upper nozzles. 

The picture is a good illustration of how the parts fit together, except the gate valve in this one is 1/4" instead of half inch, but they are pretty uncommon. 

Step 14: Step 4 - Get Ready

Check the temperatures, this snowgun will only work when the wetbulb temperatures are below -1C or 30F.  If you don't have the wetbulb temperatures on your thermometer, it will work anytime the dry bulb temperatures (the temperatures most termometers show) is below -2C or 28F.  The difference between the two has to do with the humidity level and the effects of evapouration have on the temperature (the faster water evapourates, the faster the water freezes.  Water evapourates faster when there is less of it in the air, or when the humidity is lowest). 

Position your snowmaker on your stand, ladders work well, or you can even just use a tall stake as long as it's got some substance to it, there will be a fair bit of pressure from the water spraying out of the nozzles.

Now Move your pressure washer and air compressor close to the snowmaker so that the hoses will be able to connect to them. 

Lay out your hoses and set up your extention cords (if you aren't using gas appliances), remember there is a bit of power being drawn here so you will probably need a dedicated circuit for each the pressure washer and the air compressor.

(picture coming soon)

Step 15: Start Making Snow in Your Backyard!

It's not quite that easy, follow these steps to ensure success.

1) Close your gate valve all the way
2) turn on your air compressor
3) turn on the water flow to the pressure washer
4) connect your snowmaker to your air compressor (you should be able to hear the air coming out of the snowgun)
5) turn on the pressure washer
6) open the gate valve slightly (the bottom nozzle should now have a very fine billowy mist coming out of it)
7) make snow!

If you are having trouble making snow at this point your probably have your gate valve open too much or it is not below 28F or -2C. 

The picture above isn't this snowgun exactly, I made some modifications to it, but it's essentially the same layout with an extra nozzle and pressure gauge.  

If you liked this Instructable visit my external mix snowgun guide as well:  https://www.instructables.com/id/External-Mix-Snowgun/

Here's a video of the snowgun running at the 1.5 hour mark, -4C (~25F)

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36 Discussions


6 years ago on Introduction


We're giving away a free external mix snowmaker at www.facebook.com/makesnowdotnet.

Very simple instructions, to enter simply make a video over 1 minute in length describing what you would do with all the snow you will make.

On November 6, 2012 at noon whichever video has the most likes wins and the person who posts it will be sent a free MSX-250H external mix home snowmaker from MakeSnow.Net!


1 year ago

Will it work with only a very powerful pressure washer?


2 years ago

can i just buy this from you already made?


2 years ago

I have a question about the nozzles. I'm having a difficult time finding the nozzles to purchase. I did find them on apw distributing website but they are not the same name. When I emailed customer service they told me the nozzles or meg tips as they call them, will have a set of numbers printed on them. That's what they Donny. Can you be of any help? Thank you


3 years ago

can i buy the nozzles at a local hardware stores


I will be using a 3.0 gpm pump and a 5.5 cfm @ 90 psi compressor. In your system what size nozzles will I need? Will your internal snow gun handle those parameters?

Can you predict what the reasonable expectation for the amount of snow it will make?


5 years ago on Introduction

2 questions...

Aproximately how much did it cost you for these parts?

And is a snowmaker totally necessary or can you just use a hose on mist?

Thanks, and sorry for the stupid questions...

1 reply

yes the snowmaker is necessary because if you use a hose on mist it does not separate the water enough to make it into snow and also I am not sure how much exactly this one costs but if you make it without the pressure gage it will probably be around 50$ depending on where you go to get the parts I know some online stores the nozzles can be 10 - 20$ themselves but if you look at this site you can make basically the same machine for 40$ and it has all the information where you can buy the parts (home depot or a website usually) and how much the cost. hope this was helpful here is the link : http://www.snsnowmaking.com/2011/step1-snowmaker-parts.php oh and also I dont think the pressure washers shown are 100% nessicary I think you can simpilly attatch a hose but it may not work quite as well.


Reply 4 years ago on Introduction

A great place for nozzles is www.snowathome.com

I've made several types of snowmakers and I'm currently working on a complete fan gun so if you have any questions feel free to ask or email me


7 years ago on Introduction

That looks really cool. I'm dying to do it, but I have to question whether a typical consumer pressure washer and air compressor can stand up to running for hours on end.

2 replies

Reply 6 years ago on Introduction

In my experience they generally will work well enough, however they are not meant for continuous duty, but many big box stores have a very good return policy on items that stop working.

The air compressor should be rated for continuous duty (generally belt drive and oil lubricated) but they are very difficult if not impossible to find at reasonable prices. That said most air compressors are under rated for period of performance (and over rated on horse power) and so if you keep them cool they will last for a long time. I have had the same air compressor for the last 3 years and it was $200 and I have run it for 8+ hours without any issue, but it was outside, so it was nice and cool.


Reply 7 years ago on Introduction

That is an excellent question. I am not an expert but I use both on an almost daily basis. There should be no problem with the pressure washer running non-stop (remember to change the oil as per manufacturer's recommendations) but the compressor is a totally different story. Compressors have a duty cycle that must be observed your compressor's owner's manual will list the duty cycle. 100% duty cycle air compressor are also available.


Reply 6 years ago on Introduction

CFM means Cubic Feet per Minute. It's a measurement of the amount of air that is being compressed by the air compressor and at a pressure of 40psi. The pressure washer will need to produce a minimum of 1.3 gallons of water per minute at 500psi. (many pressure washers are rated higher than this 1500psi all the way to 4500 psi, but these are maximum pressures and when freely flowing generally operate at much lower pressures, but higher volumes - like when you put your thumb over the end of a hose, more volume = lower pressure, less volume = more pressure if everything else is the same)


Reply 6 years ago on Introduction

You will get drier snow, but you will also get more drift (if there's any wind) and you will get more evaporation, so less snow (but it will be drier). Also you will be able to make snow in slightly warmer weather. So it's a toss up really.


7 years ago on Introduction

The amount of snow you make is dependent on the amount of water you can put through your pressure washer and the amount of air your air compressor produces. This set up (in this instructable) is good for between 1.3gpm and 2.5gpm for your pressure washer.

On the low end (1.3gpm, -2C or 28F, high humidity) it will make about 30 cubic feet of snow each hour.

On the high end (2.5gpm, -7C or 20F or colder, low humidity) it will make about 70 cubic feet of snow each hour.

Snow's density varies but is usually between 2 and 3.5 gallons per cubic foot (uncompacted). So you could cover an area 20' X 20' in about 6 hours with 6" of snow on the low end, or an area about 30' X 30' in 6 hours with 6" of snow on the high end.

2 replies

Reply 7 years ago on Introduction

If roughly one foot of snow equals one inch of water, then 20' X 20' X 6" of snow is about 125 gallons of water.

- 20' X 20' X 6" = 200 cubic feet
- 1 cubic foot = 1728 cubic inches (12" X 12" X 12")
- (1728 cubic inches per cubic foot) X (200 cubic feet of snow) = 345,600 cubic inches
- 345,600 cubic inches of snow / 12 = 28,800 cubic inches of water (12" of snow = one inch of water)
- 28,800 cubic inches of water = ~125 gallons of water after 6 hours

That's a lot of water. And 30' X 30' X 6" of snow is about 280 gallons of water over 6 hours.