The Magic Behind A Foam Cannon: What You Need To Know

We have all seen those photos of that amazing car dripping with rich, thick foam. When it comes to washing our rides that thick foam is the crown jewel the detailing fanatic searches for. There is just something special about it! What’s the magic behind the foam cannon that generates those amazing suds? Is it just foam cannon soap? Here we break down what a foam cannon is, its components, how it generates thick rich foam, the benefits, and proper maintenance.

Redline Finish - MTM Foam Cannon

Understanding The Foam Cannon

There are a handful of components that make up a foam cannon. There is the canister, body assembly, pressure washer fitting, orifice, filter, nozzle assembly, and soap control knob.

Canister – The canister holds the foam cannon soap solution which the foam cannon pulls from. Typically 2 to 4 ounces of soap is used and the rest water depending upon the concentration of the foam cannon soap.

Body Assembly – The body assembly is what everything attaches to: the pressure washer fitting, orifice, soap control knob, nozzle assembly, and suction hose. The body assembly is the heart of the foam cannon.

Be sure to click the link to our FREE Foam Cannon Guide (with critical orifice sizing) at the end of this post to experience and share results few ever see!


Redline Finish - Foam Cannon Body AssemblyRedline Finish - Foam Cannon Body Assembly 2

Pressure Washing Fitting – The pressure washer fitting attaches to the back of the foam cannon body assembly. There are a few different types of pressure washer fittings.Redline Finish - Foam Cannon Quick Disconnect The one shown in the picture to the right is called a quick connect and is the most common. The material type you want to use is brass or stainless steel. Which is one is better? Technically stainless steel.

Orifice – The orifice, although a small component in the foam cannon, is a big player in getting that thick rich foam you are after. The role of the orifice in simple terms is to control the amount of water/flow that comes through the foam cannon. They come in a variety of sizes and the size you need is a component of the flow rate (gallons per minute – gpm) and pressure  (pounds per square inch – psi) of your pressure washer. The typical sizes used in a foam cannon are 1.1mm and 1.25mm. They go in the back side of the body assembly (if you remove the pressure washer fitting you will see it). If you are using a pressure washer operating between 1.3 – 1.8 gpm and under 2000 psi a 1.1mm orifice is likely a good starting point.

Redline Finish - Foam Cannon Orifices

Pro Tip: Use brass or stainless steel orifices only. Believe it or not some foam cannons come with a plastic orifice and we strongly recommend staying away from those.

Filter – Redline Finish - Foam Cannon FilterOne very important component and easily overlooked is the foam cannon filter. Sure it helps filter out debris but its key role is to act as an agitator when the foam cannon soap solution and stream of water hit it to help generate thick foam. Depending upon your foam cannon some agitators are very cheap and poorly made and as a result, do not do a good job agitating. This can have an effect on generating thick foam from your foam cannon.

Pro Tip: A sure sign the filter is clogged is you are not getting the output and amount of foam from your foam cannon as you once did.

Nozzle Assembly – The nozzle assembly controls the spray pattern, turn it clockwise and you get a wider fan, while turning it counter clockwise you will get a narrower fan. If you open it too far it will just shoot out in a stream. Some foam cannons you can adjust the spray pattern to spray horizontally or vertically.

Redline Finish - Foam Cannon Nozzle Assembly

Valve knob –Redline Finish - Foam Cannon Control Knob The valve knob located at the top of the body assembly controls how much soap solution is pulled up through the suction tube. The use of this knob is debatable and is typically always closed to maximize the amount of soap solution that is pulled through your foam cannon to maximize the amount of foaming.

Is It Just The Foam Cannon Soap?

So how do you get that thick rich foam to come out of your foam cannon? Is it just finding the right foam cannon soap? Truth is, its a variety of components that when you get them all right you get what you are after…thick foam! The concentration of the foam soap is a component, also how much soap you use, the orifice size, the pressure washer operating pressure (psi) and flow (gpm), and the filter/agitator. Every foam cannon operates a little differently and it can take some tinkering to find the sweet spot. As mentioned previously, if you have a lower flow (1.3-1.8 gpm) and low/medium pressure (under 2000 psi +/-) from your pressure washer, you will likely want to start with a 1.1mm orifice. You will also very likely need to add more soap (4oz +/-) to your foam cannon to get thick suds. The spec sheet or directions on your foam cannon should tell you the minimum flow and pressure the foam cannon needs to operate properly.

Pro Tips:

  • Pour warm water into the canister, and then add the foam cannon soap, this helps generate thick suds!
  • Spray the foam on your vehicle and let it sit for a few minutes and then rinse it off to remove some of the dirt and debris off of the paint. Foam the vehicle down again and using the two bucket wash method to finish washing your vehicle. This multi step process helps reduces the chances of scratching and marring your the paint. 

*We have had great luck with the MTM Foam Cannon and Adams Mega Foam Shampoo

Benefits Of Using A Foam Cannon

Now that we understand what a foam cannon is, how it works, and the components that help generate thick suds, what are the benefits of using one?

  • Spraying the car soap on the paint surface provides a great lubricated surface to run your wash mitt over, which reduces your chances of scratching and marring your paints surface
  • The foam incapsulates the dirt particles on your paints finish to help safely remove the dirt and grime
  • Safely and effectively accelerates the car washing process
  • They are a ton of fun to use, there is just something special when you see those thick suds dripping off your ride!

Redline Finish - How to use a foam cannon

Maintaining Your Foam Cannon

Your foam cannon performance is only as good as the maintenance you perform on it. Below are a few tips you can use to insure your foam cannon lasts a long time and performs its best.

  • After use always run clean water though it to clean it out
  • Check the filter periodically and  replace as needed
  • Foam cannons typically have seals that will need to be replaced over time
  • Check your orifice from time to time and make sure it is free from debris
  • Use teflon tape to seal the pressure washer fitting on the body assembly.
  • Remove the canister from the body of the foam cannon to let it air out and completely dry
  • Use a pH neutral foam cannon soap

Wrap Up

As you can see there is a lot more to a foam cannon than just a canister with soap and a nozzle. In order to get that thick rich foam we are all after, several factors come into play along with a good maintenance program. Also, not all foam cannons are created equal. The cheap ones you find, usually there is a reason why they are that cheap,  the parts material, quality, and machining tolerances are usually pretty poor.

Using this article as a guide should help you along the way to get the performance you are looking for out of your foam cannon and identifying one that you will be happy with. We hope to have our foam cannon out in the near future.

If you enjoyed this article we recommend you check out some of our other resources located here as we are confident they will provide value to you.

Want more useful information from our extensive research and development??? People are raving about our Quick Reference Guide for maximizing your foam cannon use…

Give me the guide.

I want MAX foam and performance!

The FREE orifice guide itself is worth the click…


We hope your detailing experience is amazing! 

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3 thoughts on “The Magic Behind A Foam Cannon: What You Need To Know

  1. Nice to see a good post on foam canons. You beat me to it. 🙂👍👍👍

    1. Thank you! We are glad you enjoyed it! Please do write yours, it never hurts to have a couple good articles on a topic. Stay safe and healthy!

  2. This is a great article and you are banged on with your points about the magic behind a foam cannon what you need to know. Be clear about what you really need and want to accomplish at this point- you are right with this point.

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