Pressure Washer PSI for a Foam Cannon – Answered

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If you have ever tried car washing with a generic garden hose, you know how frustrating it can be. By using a foam cannon with your pressure washer, removing dirt and grime is faster and easier. Before you try this however, the water source must provide the right amount of PSI. That will be explained in this guide along with other requirements.

Pressure washer foam cannons need at least 1500 PSI and 2.0 GPM for the best results. Some foam cannons can handle up to 5000 PSI and 5 GPM. The maximum capacity and water volume requirement can also vary depending on the pressure washer.

What PSI Do Pressure Washer Foam Cannons Need?

PSI (pounds per square inch) is a measurement of how much force water produces. Foam cannons require at least 1100 PSI to run. However, majority of high end foam cannons need at least 1500 PSI and can support up to 5000 PSI.

GPM (gallons per minute) refers to the volume of water flowing through the pressure washer. The rate is measured in gallons per minute. Foam cannons usually need at least 1.5 GPM to operate, though more powerful models require at least 2 GPM. Some foam cannons can work with up to 5 GPM.

Because pressure washers need a significant amount of PSI and GPM, you cannot use a kitchen faucet as a water source. While you can connect a pressure washer to a kitchen tap , it is not sufficient for foam cannons.

A typical car pressure wash needs 1500 PSI and 1.5 GPM. Even if the foam cannon supports higher PSI, do not use it as the force could strip away car paint.

What Foam Cannon Type Should I Use?

There are lot of foam cannon attachments available, but basically there are two types: professional and consumer grade.

Consumer grade foam cannons. These are the most commonly used by car owners and ideal for most. These foam cannons are compatible with consumer grade pressure washers and are low cost, effective and easy to use. One of the best options available is the Tool Daily Foam Cannon which is good for 1000-3000 PSI pressure washers and includes multiple nozzles.

These foam cannons are designed to be cost effective. While not as durable as their professional level counterparts, they work fine. If you wash your car only during the weekends then these foam cannons are ideal.

Professional grade foam cannons. As you might expect, professional or commercial grade foam cannons are more durable, have better fittings and suited for heavy duty use. These are more expensive but can also last longer.

How to Use a Foam Cannon with a Pressure Washer

Using a foam cannon is straightforward and works with gas and electric pressure washers. But you must have the following.

There are a lot of foam cannon soaps available, but you only need to remember three things.

  • The soap must be pH neutral so it does not damage the car.
  • The soap has to be designed for the entire vehicle, including the lights, windshield, tires etc. An all-around soap simplifies cleaning and you do not have to be concerned if a particular part gets soap on it.
  • Lots of suds. The more suds, the more dirt the foam cannon can wash off.

This video shows you how to use a foam cannon to wash a car. If you prefer a step by step approach, keep reading.

Wash the car first. You can use a bucket of soapy water or a garden hose. The goal is to remove loose grime. While some like to use the foam cannon right away, washing first makes the foam even more efficient.

  1. Plug the foam cannon onto the pressure washer spray gun. Spray guns and wands have connectors for foam cannons so you just have to plug it in.
  2. Pour foam cannon soap into the container. Add warm water. Follow the mixing instructions that come with the soap.
  3. The foam cannon is now ready to use. You can control how much foam comes out by adjusting the knob at the top of the foam cannon.
  4. There is another knob at the front that enables you to control the fan pattern. You should also check your car owner’s manual for any specific PSI and GPM suggestions.

After you are done cleaning with the foam cannon, you can give the car another wash with a bucket of water or hose. Remove the foam cannon from the pressure washer and rinse it under running water.

Why Do You Need the Right PSI For a Foam Cannon?

If the foam cannon PSI is too high it can damage your vehicle. It can remove the paint or scratch the surface. If the PSI is too low, the pressure washer will not be able to remove the dirt.

When you use the right PSI, a foam cannon gets the cleaning done efficiently. Here are the reasons why.

Lots of soap suds. The more suds and soap a foam cannon produces, the greater the amount of dirt that will be removed. When the PSI is at the right level, your pressure washer produces plenty of soap suds without damaging the car surface.

A foam cannon eliminates the risk of scratching the vehicle surface. No matter how careful you are with a mitt, sponge or brush, there is always the chance you could damage the paint. By opting for a foam cannon only the right PSI is used.

Car washing with a bucket of water removes dirt but not as well as a foam cannon. Cleaning with a bucket is also impractical. When you dip your mitt or brush in the water, it gets dirty. The grime you removed ends up in the bucket and back on the car.

In comparison, a foam cannon only uses clean suds. The continuous water flow washes the dirt off and leaves the surface clear. As long as the water source is clean and there is ample soap, you can let the foam cannon run without worry of dirt getting back on the car.

Frequently Asked Questions

Why is the foam coming out of my pressure washer runny?

There is either too much water in the mix or the PSI is too low. Increase the PSI to 1500-2000 and try again. If that does not work, use warm water for the mixture.

How often should I clean a foam cannon?

After every use. Empty the container and wash it under running water. Clean and wash thoroughly until all traces of soap are gone. This is essential to keep it working.

Can I use any type of soap with a foam cannon?

No, you must only use foam cannon soap. Regular soap cannot remove dirt the way foam soap does. Worse, there is no telling what regular soap will do to the car paint. If you want to be really safe, check your car owner’s manual for any recommendations.

Is it necessary to scrub when using a foam cannon?

No. The force of the pressure washer and the soap suds are enough to get rid of the dirt. The amount of pressure you apply with a mitt is not as effective as that of a foam cannon. Foam cannons are also safer and do not risk stripping the coat.

Should you hand wash the car after using a foam cannon?

You have to rinse the car after washing. Some use a garden hose, others prefer a pressure washer at a lighter setting. And some like to hand wash the car with a bucket and mitt. There is no consensus, but what is important is that you rinse the car afterwards.

Is it safe to foam cannon an engine?

Yes, as long as it is low pressure. Make sure the cleaning solution is made for engines and will not corrode the metal. Follow the instructions provided in the cleaner before proceeding.