A Foam Gun is NOT a Foam Cannon- Here’s the Difference

Foam guns vs. foam cannons – these two terms regularly get mixed up by detailing enthusiasts. While they perform a very similar job, they are not the same.

A foam gun connects to a garden hose and uses low-pressure water to spray diluted soap on your car. A foam cannon connects to a pressure washer and uses high-pressure water to create a thick, cream-like foam that clings to your car for longer. Both can use the same soap but deliver a different result.

You’ve probably seen the videos on Instagram and YouTube of people covering their cars with foam and thought it looked like fun. If you’re considering adding one or both of these tools to your detailing arsenal, this will be a great way to learn about each of them. Either option will give you more suds to protect your paintwork but there are different uses and cases for each.

The Biggest Difference Between a Foam Gun and a Foam Cannon

Let’s start by covering the differences between the two. A foam gun can be purchased for around $30 and that’s really all you will need. It screws right onto the end of your garden hose and only requires standard water pressure to work. Setup will take you less than a minute; just remove your current nozzle and install this one. 

A foam cannon isn’t much more expensive, but here’s the big caveat: you need a pressure washer to use one. Electric or gas powered is up to you, but you’ll want to make sure you have a minimum of 1,100 psi for most cannons. A maximum pressure of 3,000 psi is a common specification. Plan on spending $200 for an electric pressure washer or $350 for a gas one if you don’t already own one.

Putting more pressure through your cannon is going to give you a thicker foam versus a runnier mix that won’t stick as well.

If you’re investing in a pressure washer solely for the purpose of being able to use a foam cannon, you’ll probably want to shell out a few extra dollars to make sure you have adequate power- don’t go with the cheapest one available because you’ll probably be disappointed with the performance. When shopping for a pressure washer or cannon, check the specs to see what the flow rate is as well. A flow rate of 2.0 gallons per minute should be sufficient for most cannons.

Advantages of Using a Foam Cannon

I believe you can wash your vehicle with just the ol’ two bucket method and avoid swirling your paint if you’re careful about it, but that doesn’t mean it’s the best or easiest way to get the job done. Using a foam cannon gives you so much more lubrication for the whole process.

It’s like the first time you dip your mitt into some fresh suds and get started. Even using the two-bucket method (which I would still recommend doing while using a foam gun or cannon), you’re still gradually contaminating the soap bucket which increases the risk of marring.

Makers of cannons and shampoos also claim that a thick foam will encapsulate the dirt and carry it off the surface. I’m not really sure if that’s ever been proven under a microscope or if it’s just marketing fluff, but it is nice being able to get soap into areas you can’t physically reach like around lights, grilles, and trim.

Bear in mind, you will need to take your time with the final rinse, or end up like me,  blowing out soap from under the spoiler when drying it with a leaf blower. I can say for a fact that your wash mitt will glide over the surface with less resistance than you’ve ever experienced. It’s a great feeling, and honestly, it’s just so much fun to use!

Having a pressure washer at your disposal is great for other reasons too, like blasting away the majority of the loose dirt before you get started. But as with most things, there are some precautions to take when using a pressure washer. Using the wrong tip, having too much pressure, or being too close could damage paint, push water past seals, or tear trim and decals right off your vehicle.

You’ll also want to make sure the tip of the foam cannon is securely attached before pulling the trigger when pointed at your car. You do NOT want to use 3,000 psi to launch a heavy piece of brass at it! The cannon will attach to your wand with the same quick release style fitting that is already on most pressure washers, so installation is very easy and doesn’t require any tools. 

In my experience, the cannons tend to use less soap than a gun. Figuring out the right ratio to get the foam to your liking is a bit of trial and error, but I would say start with 1 oz of soap to 10 oz of hot water. 

Here’s the sub $20 cannon that I acquired through Amazon:

Example of foam coverage using ~2,700psi and Chemical Guys Mr. Pink shampoo. I thought this worked well and they advertised that it worked well with cannons, but I recently learned they have another product called “Sticky Snowball Ultra Snow Foam” which may yield thicker spray. I’ll be giving that a try once I burn through this. 

Advantages of Using a Foam Gun

Personally, I enjoy washing my vehicles early in the morning because I hate working in the heat. The foam gun notches a point here because I don’t think my neighbors would enjoy hearing a gas-powered pressure washer at 7 a.m.

It also gets another point because it really doesn’t add any more time to the process of getting set up and putting things away after. But, while it will cover your car with suds and give you that extra lubrication to avoid surface marring, it just doesn’t stick the way foam from a cannon will. While you will get good coverage, most of it is going to run off pretty quickly.

The other thing I dislike about using a foam gun is how quickly you burn through your soap! The bottle has a line on it for the recommended amount of soap, then you fill the rest with water. You’re going to need to move the gun quickly, and if you have a large vehicle, you’ll probably end up running out before you do the whole thing.

All guns will have a dial where you can adjust how much soap you’re using, but if you’re like me, you’ll end up going heavy on the mix so you can get more suds on the paint. If you’re after a cheap, easy to use tool that will improve your wash process, a foam gun is a great addition.

Foam guns are also much smaller and easier to handle than a cannon attached to the long wand of a pressure washer. A foam gun can be operated with one hand instead of two which makes it easier to safely move the hose around your vehicle without it hitting or getting snagged on the tires.

The pressure washer I use doesn’t have a very long hose on it either, which requires repositioning at least once during the process and feeling it hammering away right next to your eardrums. Mine is gas powered so I get to enjoy the heat coming off of it and the exhaust fumes too.

The best advice I would give someone planning to go with a foam gun is to buy a good soap that is designed for creating foam. I’ll be honest, the first time I used a foam gun, I tried using the same Meguiar’s stuff I use for a traditional wash. It was the equivalent of just dumping a bucket of soapy water on the car. It ran off almost instantly!

After that first disappointing trial, I sat it aside, and it has been collecting dust for almost a year. Then I figured that I should probably give it a second shot with this new Chemical Guys Mr. Pink that had good reviews on Amazon. Wow! Night and day difference!

I also learned that most users say to dilute with hot water for better foam action so I’ve been doing that as well.

Here’s the foam gun I use. I’ve heard the same one is available for less money without the Chemical Guys branding, but this one was a gift from a friend.

This is what happens if you don’t use a proper soap:

Here’s the same gun, same foam setting, but using the Mr. Pink shampoo. The foam is much thicker, and coverage is immensely better. It doesn’t run off the surface as fast either.

Are Cheap Foam Cannons as Good as Expensive Ones?

There’s an extremely wide price range of foam cannons on the market right now. I’ve seen them on Amazon for under $20 and commercial grade ones going close to $200. The higher end cannons are going to use more metal parts versus plastic on the more budget friendly units.

While every cannon seems to give you some control over the soap mixture, a premium product will give you finer adjustability and allow you to dial in the spray pattern to your liking.

Buying a name brand product from a reputable seller will also give you access to spare parts while the $19.99 Amazon special will likely become a disposable product. That’s the route I have chosen to take. If I enjoy using it enough and it fails me in short order, then I’ll splurge for something nicer.

Who knows, maybe it will last a while; there are some cheap ones that have thousands of good reviews. I will say that the foam control on the one I have is not intuitive, and they didn’t include much in the way of directions.

It has a +/- on the “foam control” knob so I assumed ‘+’ would mean more foam… not the case! I was extremely disappointed the first time I used it and immediately decided to try max foam and got worse results than the foam gun.

Summary

Foam guns and foam cannons are both great tools to add to your collection if you enjoy keeping your car clean and it makes you a little nauseous to see swirl marks in the paint.

Cannons have the upper hand when it comes to creating the thickest foam and being incredibly fun to use. But while guns offer less performance, the total cost is significantly lower, and using one won’t add much time to your setup and tear-down.

Take a shot with either, but whichever you choose, I bet you won’t want to go back to doing it the old fashioned way.