You may have seen foam sprayed or applied to vehicles, but what are the advantages? And what’s the difference between a foam gun vs foam cannon? These tools are a great investment for many people, but it really depends on your level of detail when washing your car. For example, are you trying desperately to avoid swirls in a professional setting, or just looking to clean the dirt off from time to time?
In this blog, I’ll break down the differences between foam guns and cannons, what to expect from them, and why you may want to use one or the other. They actually do have some benefits over traditional hand-washing!
Why Use Foam Guns or Cannons?
When it comes to washing your car, these devices really just assist in applying soap, the key component to trapping dirt and removing it safely. Enough soap will help dirt slide right off a car, but the challenge is that it’s sometimes hard to apply enough suds using a wash mitt and bucket alone.
Traditionally, most people you talk to probably fill their bucket with suds, spray down their vehicle, and then apply soap to the surface in a circular motion with a mitt. This can lead to swirl marks.
Swirl marks are basically tiny circular scratches that are produced when you rub a wash mitt over a really dirty surface. When you break it down, this dirt is really just made up of tiny jagged particles (rocks, and other debris).
Even with some suds on your mitt, there’s sometimes not enough lubrication to prevent large dirt particles from scratching your clear coat when you apply pressure.
Advantages of using foam
One of the reasons why some detailers prefer to use foam guns/cannons, is that the foam produced helps break down heavy dirt without agitation.
By applying suds with zero agitation, heavy layers of dirt can begin to run down the vehicle’s surface without you even touching the paint.
Don’t get me wrong, agitation is the best way to remove dirt, but also increases the chances of swirl marks if you have a lot of dirt to deal with.
By starting with foam, you help reduce that risk by taking off most of the dirt, before rinsing and going back over with a second layer of foam and a wash mitt.
Foam Guns vs Foam Cannons
Many people tend to use these terms interchangeably, but they are in fact different. Foam guns are really geared towards car enthusiasts instead of detailers, are generally cheaper, and do not produce the same type of foam.
What is a Foam Gun?
A foam gun is basically a device that attaches to your standard garden hose adaptor with a special sprayer attachment that attaches to a tank. This is really perfect for people who do not have access to a pressure washer (or prefer not to haul it out) when washing in the driveway.
What is a Foam Cannon?
Foam cannons, on the other hand, are designed to be used with pressure washers. One advantage is that foam can be applied faster at somewhere around 1-5 gallons per minute. The pressure also creates a thicker and richer foam which is beneficial for maximum coverage.
These 5 electric pressure washers I recently wrote about fit the bill are a lot cheaper than many gas models on the market and are perfect for at-home use with a foam cannon.
Foam cannons are generally preferred by detailers because they are higher quality and allow more foam to be applied to the surface much faster.
What Soaps to Use with Foam Guns or Cannons
At the end of the day, it really doesn’t matter too much what car soap you use, as long as it is safe for clear coats. With that said, some products like Meguiar’s Hyper-wash are specifically designed for foam cannons (and guns) because they produce thicker suds and are usually more concentrated.
Some guns and cannons eat up any soap you use pretty quickly, which is why many of these ‘snow foam’ concentrates come in large containers. Below are a few common ones I’ve heard about that you may want to read about on Amazon:
- Chemical Guys HoneyDew Snow Foam – 1 Gallon
- Adams Ultra Foam Shampoo – 1 Gallon
- McKee’s 37 Foam Formula- 1 Gallon
Keep in mind that some of these cannon and guns do come in kits with the device, soap, and sometimes a towel shipped that can be shipped to your door.
How to Apply Foam to your Car
To best prevent swirl marks, it’s important to use foam correctly. It really doesn’t matter if you use a cannon or a gun, the principles still really remain the same. Before getting started, make sure you use foam in the shade, or in an area where there isn’t direct sunlight to prevent the foam from drying.
Fill your foam gun tank with suds (per the device instructions) and attach the gun to your hose.
Step 1: Rinse off your Car
With only water, start by rinsing off your vehicle just to remove any surface dirt and loose debris. You never want to apply soap to a dry, non-lubricated surface.
Step 2: Apply a thin layer of foam
Apply a layer of foam to one section of your vehicle and let it run down your car for about 20 to 30 seconds. This could be the hood, door panels, or trunk. I find it’s usually easier to work in sections.
Step 3: Rinse off the foam
Without touching the car, rinse off the foam with clean water, and continue to step 4.
Step 4: Apply a second layer of foam, use a mitt, and rinse (optional)
Step 4 basically repeats step 2. The only difference is that this time you will want to run a soapy wash mitt behind the suds to assist in sliding dirt off the car. For best results, dip your mitt in a clean bucket of water along the way to avoid trapping dirt (2 step process), before adding more suds to it.
Simply rinse one last time, and you’re good to go.
What to Keep in Mind
If your vehicle is relatively clean (or you aren’t worried about swirl marks), you can just use a wash mitt during step 2. Again, you want to use minimum pressure and plenty of soap for lubrication when using a mitt, only enough to graze the surface.
For best results and for pristine paint jobs, don’t touch the paint until step 4, since the water in step 3 will remove the dirtiest suds. You reduce the risk of swirls dramatically the less dirt you have remaining on the vehicle before agitation.
While there are several companies that make some pretty good models, I’ll break down a few good choices for car enthusiasts that are looking to get started with applying foam.
This is one of the best values as far as foam guns go, and provides quite a bit of customization. This one has stainless steel fittings which I would recommend for any detailer or enthusiast, since some models may come with plastic hose attachments that can crack or leak.
This one has what’s called a metering tip that controls the amount of foam produced. I have some of the cheaper ones that regulate foam with a dial, and they absolutely kill your fingers trying to adjust. Pretty painful actually!
Since this one has a quick disconnect, just spray the foam, disconnect the hose, and rinse away.
There are a bunch of different foam cannons available, but it really depends on personal preference. There are some higher-quality foam cannons on the market, but unless you are a serious detailer that prefers the best of the best, it simply may not be worth the investment.
This is one of the the nicest models I’ve found that also comes with a ‘snub nose nozzle’ which sort of resembles a gas pump. I’ve you’ve ever used a foam cannon at a car wash, this is the type of trigger mechanism used. If you’ve used cheaper foam cannons before, you may want to try this one. It makes applying foam a little more convenient by adding a trigger attached to the unit (instead of using a longer pressure washer lance as pictured above)
Another cannon on the higher-end side is this model by MTM Hydro. It’s actually one of the best at regulating the spray pattern and has a few more adjustments.
This one (and many others like it) have a ton of different foam settings and uses a bit less soap than cheaper cannons. This model has adjustable air intakes and fan blades, can spray foam up to 20 feet, and is ideal for RVs or large vehicles
Last but not least this one (or similar) I would recommend for beginners or hobbyists since it is so affordable. This one was around 20 bucks the last time I checked, has brass attachments and is really all you need if you’ve never used a foam cannon before.
However, if you deal with high-end clients, the more expensive cannons may actually be worth the investment if you are an advanced detailer with the money to spare.
Keys to Producing Thick Foam
There are a few tricks to producing that thick, shaving cream-like foam you may have seen in videos. One of the most important is obviously the device type since cannons produce thicker foam than guns due to pressure. Here are a few other important factors:
Your Pressure Washer
Gas pressure washers are going to give you the most power right off the bat, which is important when producing foam. Usually, you need around 2.0 gallons per minute at a minimum which some electric pressure washers struggle to achieve. Just make sure you check the ratings on your pressure washer.
If you are having trouble with high-quality soap not producing thick foam, make sure you dilute it according to recommendations. 20% of the container filled with soap, and the rest with water is pretty standard.
Orifices and Cleanliness
Foam cannons come with these orifices (usually 1.1-1.25 mm) that can really be the difference maker when it comes to how much foam is released. These tiny little brass fittings can be purchased separately. Check out this YouTube video for a better explanation.
You also want to remove the tank from these cannons and flush the lines with clean water periodically to prevent corrosion.
Some soaps are actually better at producing foam as mentioned earlier, so be sure to pick up one of the recommended soaps if you’re having problems with cheaper non-foaming car soaps. Some are just not meant to create as much foam.
Foam is pretty cool, so if you are thinking about purchasing a foam gun or cannon there are plenty of videos and resources you can find depending on your particular model. One word of caution is to be careful when deciding on the more expensive ‘private label’ foam cannons/guns and soaps.
Often times these are just very generic devices with fancy colors and logos, but $50 or $60 more expensive. The same really goes for soaps for the most part. Always be sure to read reviews, check the physical components used, and do your research!
I hope this post has been helpful if you’re looking for a better way to apply soap. These devices can help speed up your wash process and are really not a bad investment for the average car enthusiast looking to remove dirt a lot easier.
New to detailing? Check out my free eBook, 25 Essential Auto Detailing Products for Beginners for more products that can improve your detailing ability.