Everyone loves saving time on DIY projects. Whether it’s removing a step from a maintenance project, or using better tools to build a fence, streamlining your workload – while improving the quality of the finished results is the goal of every DIYer. This is a major reason why dedicated car enthusiasts use foam guns or foam cannons in their car wash kit or a first step to wash your car.

The usefulness of foam cannons and foam guns for washing has been one of the most debated discussions within the detailing industry for years. Some consider them soap suckers, that don’t provide much value, while others wouldn’t attempt to wash a car without one.

Nevertheless, a foam gun can be a helpful tool to help provide superior lubrication, reduce scratches, lift dirt and grime, and help to expedite your car washing and detailing projects. They can also be helpful for removing wax – if prepping to apply a ceramic coating or a paint sealant.

Foam Gun vs Foam Cannon - Exterior Detailing Nissan 350z

For those without coatings, you can also use them to apply wash and wax soaps. So, if you’ve been looking for a guide to car wash foam guns, you’ve found the right article.

In the information below, we’ll outline some facts about foam guns, introduce the different types of foam guns, compare a foam gun vs a pressure washing foam cannon, and explain the pros and cons of using them for car washing projects.

Is there a Difference Between Foam Gun and Foam Cannon?

Adams Foam Gun vs Foam Cannon Comparison Review

Making an investment with any car care tool is all about personal preference. One tool that has grown in recent years is the foam gun. This attachment to your average garden or industrial-strength spray nozzle on a garden hose is designed to mix car washing soap, spread a thick layer of wash shampoo foam on the vehicle surface prior to washing it by hand.

But, that’s what a foam cannon does as well. This leads to a lot of confusion about comparing foam guns vs foam cannons for cleaning.

prototypical foam gun for car wash
The image above is your prototypical foam gun.

Delivery of Water to the Foam Container

To simplify, the main difference between a foam gun and foam cannon is the method of ‘delivery’ of water to the foam container. A foam gun uses a standard garden hose (with a custom attachment on the nozzle tip usually), while a foam cannon is attached to a high-pressure hose.

Benefits of High-Pressure Spray Nozzle

Naturally, the higher-pressure spray nozzle and volume is going to agitate the soap quicker, more efficiently, and generally, create thicker foam soap suds for removing grime. This helps to reduce swirl marks when applied correctly.

Obviously – you don’t use a foam gun or cannon with a waterless car wash Now, here is the $50 question – is the added volume of soap and suds going to improve your washing ability or clean your car better?

foam cannon for car wash
This is a foam cannon – which is attached to a high-pressure hose and pressure washer.

Well, not really.

In fact, there really isn’t any science to prove that the foam from a cannon or lance is “better” than that from a foam gun. They both are mainly designed to pre-soak the vehicle’s surface with a thick layer of automotive car soap or shampoo.

Once applied, the foam will begin to loosen contaminants, helping to remove dirt, debris, bird droppings, bug splatters and more. You then wash the car as normal, and dry with microfiber towels, drying towel or air-drying methods.

Which is Better – a Foam Gun or Foam Cannon?

To Foam or Not to Foam, That is the Question

That’s another popular question that really depends on your preference – but also, supporting equipment. If you already own a high-pressure washer, it naturally makes sense to invest in the foam lance or foam cannon. This product is designed to work in conjunction with the accelerated volume of water.

If you don’t have a high-pressure washer, but own a standard garden hose, the foam gun is your most economical and logical option. They’ll both produce ample amounts of soapy suds to do a great job of pre-soaking and pre-washing the vehicle.

What are the Types of Foam Guns on the Market?

Detailing the Zr1! Are FOAM GUNS better than FOAM CANNONS?

To be truthful, there are only two types of foam guns available to automotive enthusiasts – adjustable and non-adjustable. The adjustable foam guns were revolutionized by Gilmour – an American company that specializes in plumbing solutions for garden, automotive, and lawn care applications.

In fact, here is an interesting tidbit. Did you know that the technology used with foam guns for car washing is based mainly on mixing gardening fertilizers or bug sprays? Ortho (a landscaping chemical manufacturer) initially designed a spray gun and barrel attachment that would mix chemicals for helping grass and plants grow.

This technology found a home in the automotive space when Gilmour redesigned the foam gun about 20 years ago. Now that you’re aware of its history, let’s get back to basics.

how does a car wash foam gun work

Adjustable Foam Gun

The adjustable foam gun has a selector switch or knob that blends the volume of water vs the amount of soap it will mix. The settings are generally from 0 (which is straight water through the gun – for rinsing) to 5 or 6 (which delivers the higher level of soapy suds).

Non-Adjustable Foam Gun

The non-adjustable foam gun is a simple attach and spray version. You’ll fill the foam gun with the recommended amount of soap (based on the thickness of suds you want) – and spray away. While these are non-adjustable (with regards to soap volume) – they usually have a selector switch for rinsing.

There are some that do not have this option, meaning you need to quick-disconnect the spray nozzle from the foam gun to rinse off.

Most foam guns are patterned after Gilmour’s revolutionary design. Some are made from cheap plastic materials, and will cost around $30.00 – and others made from more durable materials (such as brass – stainless steel or stronger polymers). These typically will run you at least $50.00.

How to Use a Foam Gun

Foaming Car Without Power Washer - Foam Gun Car Wash

If you’re going to invest in a foam gun, it’s important to determine whether you feel comfortable with its usage. Use a car wash shampoo that’s formulated for creating lots of suds. Now, let’s be clear – while most foam guns are identical in their design, settings, and intent of use, each one has different, recommended steps.

It’s always best to follow the manufacturers’ exact instructions for the best results.

So – here are a few general steps for using a foam gun.

Step 1 – Gather Supplies

Most automotive foam guns require a garden hose, spray nozzle, the quick connect, the foam gun soap barrel, and foam spray attachments. Most foam guns come with everything you need – except the garden hose.

Step 2 – Select the Right Car Shampoo or Soap

which foam gun soap is better for car wash

There are several types of foam gun automotive soaps or shampoos to consider.

Maintenance Automotive Shampoo

Some people (including myself) prefer to use the same maintenance automotive shampoo (that can be used in a foam gun or handwashing bucket)

Foaming Shampoos

However, some detailers and automotive enthusiasts like to use accelerated suds or foaming shampoos for their foam guns. Again, I haven’t seen any science to back up how these snow foam products are any ‘better’ at washing your car, but if it floats your boat – have at it.

How to Choose a Soap?

The key is to choose a soap that works best for your application. If you have a high-quality Ceramic Coating applied to your vehicle, I strongly recommend using a pH neutral or balanced car soap. The soap should be very slick, highly concentrated, and provide enough lubrication to allow your wash mitt to smoothly glide over the vehicle surface.

Step 3 – Mix the Soap in the Foam Gun

mix soap in your foam gun for car wash

Some foam guns are quite simple to measure soap – you’ll simply fill up the barrel and adjust the percentage of water flowing into it. Others are a bit more complex. Regardless, automotive detailing manufacturers are quite good (well some of them anyway) at providing instructions for the correct dilution ratio.

Pros and Cons of Using Higher Concentration of Soap

There are some pros and cons to using a higher concentration of soap to water.

First, more soap coming out of the nozzle can clog the spray nozzle or water jets inside the foam gun. The less soap used, is less likely to cause obstructions. Think of it like eating a bacon double cheeseburger vs a chicken sandwich.

Second, sometimes, when you use more soap, the foam will be thicker – but dry faster. Again, it depends on the type of soap or shampoo you use.

Third, not using enough soap or shampoo will basically be pointless. The intent of a foam gun or foam cannon is to provide a thick layer of soap, so it can begin the process of lifting and separating dirt, debris, and other contaminants.

So – make sure to follow the manufacturer directions (both the foam gun and the soap used) – for optimal results.

Step 4 – Add Water to Foam Gun Barrel

Do Foam Cannon's Really Work - Yes & Why!

Again – this step might be irrelevant to the foam gun you purchase. Some of them require you to add some water to the soap (as a pre-mix). However, there is a wrong and right way to accomplish this.

What Not to do

One thing NOT to do – is to add the soap, then spray water into the barrel. This will create too much ‘foam’ inside the barrel and reduce the amount of spraying to the vehicle. It’s also not advised to use dish soap in a foam gun.

Here is a helpful hint I like to follow. Fill up one of your washing buckets with plain water (the one you’ll use during the two-bucket wash). Add the recommended soap to the canister first, then slowly dip the barrel into the clean water until it’s filled to the desired level. This will mix the soap and water, but not agitate it.

Step 5 – Attach the Spray Nozzle to the Foam Gun

Finally, you’ll attach your foam gun barrel to the housing, and then to the spray nozzle itself. Again, each foam gun will have unique attachments and parts, so follow their recommended steps for final assembly and use.

What Do We Recommend – Foam Gun vs Foam Cannon?

why foam gun is a better choice for car wash

Focused on Simplicity

If you are looking for simplicity – the non-adjustable with a selector switch for straight water and foam soap suds are your best option. These foam guns are very easy to use and can be the most economic version – as they don’t use a tremendous amount of soap or detergent. Believe it or not – many professional detailers do not use them.

Perfect Application

If you like to fiddle with stuff until you find the perfect application, the adjustable foam gun is right for you. One thing you should be aware of is excessive soap usage with higher settings on foam guns. You’ll get more soap on the vehicle, and the suds will be thicker and take longer to dry, but you’ll use about three-times the soap volume.


If you’re a penny-pinching DIYer that buys products based on ‘cost per wash’ – the adjustable soap foam gun with a soap bottle set on the lower controls is going to deliver you the best value.

Wrapping it Up

Using a foam gun as a pre-wash formula and method is very effective at providing a base layer of suds on the vehicle prior to wash. The more aggressive the foam, the more lubrication you’ll produce – and thus, resist scratching during your car washing.

The key is to purchase a foam gun that is made with high-quality materials, that will hold up to constant use, is easy to use, and provides you with the flexibility to configure it to your personal preference.

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