Foam cannon or foam gun: Which should you choose?

Foam cannon or foam gun: Which should you choose?

By now, you’ve probably heard of foam cannons and foam guns. Though the two tools have similarities, they are different tools with unique ways of operating them. This post will explore the differences between foam guns and cannons, along with the benefits and drawbacks of each. 

The main difference between foam cannons and foam guns is that cannons are used with pressure washers, while guns attach to a standard garden hose. Many favor foam guns for convenience; others prefer cannons for their stronger cleaning power. 

Why use foam cannons or guns?

Both foam cannons and foam guns can make washing your car quicker, more effective, and even more fun. Either device will quickly cover your vehicle with tons of suds. The thick foam helps the cleanser cling to your car’s surface longer, allowing it to lift off dirt and debris. The lather will give you more time to work before the cleanser drips off your vehicle or dries prematurely. Finally, foam also helps you to see which areas you've already scrubbed with your microfiber wash mitt or brush.

What is a foam cannon?

Foam cannons are wash accessories that attach to a gas or electric-powered pressure washer. Almost all foam cannons have three parts: a solution bottle, a suction tube, and an adjustable barrel assembly. Generally speaking, foam cannons come pre-installed with a ¼-inch male quick-connect fitting that will easily join to ¼-inch female quick-connect fitting pressure washers – the size most brands use. 

How to Use a Foam Cannon 

Ensure your other washing supplies are ready before putting together your foam cannon. Gather your hose, buckets, wash mitts, drying towels, etc. Assembling the foam cannon is the hardest part; it’s easy to use. 

To prepare your cannon, connect the clear suction tube to the underside of the barrel if it is not already attached. Next, fill the canister with water until it is roughly 75%-80% full, and then add your preferred foam cannon soap. 

If you’re using Stoner’s MOAB Foam Cannon Ammo, you’ll want to use about an ounce of soap per gallon or bottle. Always check the back of the foam cannon soap you’re using before use for proper dilution instructions. Know the saying a little bit goes a long way? That’s the case when using foam cannon soap. Too much soap can clog the foam cannon and cause a mess that’ll take time to clean up. 

Once you’ve added your soap, shake the cannon bottle side-to-side to help the soap mix into the water evenly. If you haven’t done so already, rinse off your vehicle. Keep the nozzle at least 12-18 inches from the car’s surface if using the pressure washer. If you’ve already rinsed, screw the canister onto the bottom of the cannon to ready it for use. 

You’ll find two adjustment knobs for the foam cannon, one to control the flow rate and another to set the spray pattern. As a general guideline, use the following initial settings and then fine-tune them as you work.

Cannon Knob   
Initial Setting   

Top Adjustment Knob

Turn the top adjustment knob clockwise to the right to tighten it, then make a ¼ turn to the left to open it for an initial setting.

Barrel Knob

Tighten the barrel knob completely, then loosen it to create a 1-2 mm gap between the knob and the cannon’s main body.


Begin with these settings and adjust them to suit your preference and cleaning needs. Spray the vehicle with foam, working from top to bottom, then wipe your car with a microfiber or wash mitt. 

Thoroughly rinse any remaining cleaning solution using clear water, and towel dry with a clean microfiber towel.

Is there a specific pressure washer you should use? 

What about the powerhouse of the foam cannon - the pressure washer? There are plenty of options. You can find pressure washers powered by gas or electricity. Both will work for foam cannons, but you’ll want to pay close attention to the PSI (Pounds per Square Inch) and GPM (Gallons Per Minute) stats. You’ll want a pressure washer that produces a minimum of 1100 PSI and 1.5 GPM. Ideally, a pressure washer in the 1,700 PSI range works best. If you want to generate thick foam, use a pressure washer with a GPM of 2.0 or higher. 

Both gas and electric pressure washers will get the job done, but many believe that gas pressure washers perform better and have more power. However, gas washers take longer to set up, require more maintenance, and are louder during operation than electric pressure washers. Electric washers plug in for use within minutes and work well for light cleaning.

Either pressure washer works, so consider the benefits and drawbacks and choose whichever best suits your needs. 

What is a foam gun? 

Because foam guns attach to your household garden hose, they are a fast, easy option for people who want lots of suds without using a pressure washer. Foam guns work similarly to foam cannons in that they mix water, cleanser, and air to create suds that coat your vehicle. Like a foam cannon, the lather from a foam gun helps cleanse and lubricate your car's surface throughout the wash. 

Foam guns have more parts than cannon counterparts, including a spray nozzle with a trigger, a suction tube, and, in some cases, metering tips to offer various flow rates. Metering tips differ in size and allow the liquid in the canister to move through more or less quickly. These tips can be press fit or threaded, so refer to the product description of the gun you purchase. 

Something to know: While foam guns create suds, you won’t produce foam as thick as you would from a cannon. Foam guns simply lack enough water pressure needed to produce super dense lather. While the gun will coat your car with frothy soap, the foam will not stick to your auto’s surface quite as well. Expect to get excellent coverage that will run off fairly quickly.

How to Use a Foam Gun 

Setting up a foam gun is similar to setting up a foam cannon, except there is no pressure washer involved with a foam gun. 

Decide whether you want to alter the flow rate of your foam gun by using a metering tip. If you choose not to use a tip, you will create the maximum amount of suds by allowing water to pass through the device more quickly. Using a metering tip will cut down a bit on the foam; however, you will also conserve cleanser within the canister, allowing you to wash longer without a refill. 

Consider diluting your soap using hot water to boost the foam production of your gun. Measure out the car wash soap to create the correct dilution ratio according to the directions on your bottle, and gently swirl to mix. If you don’t use enough soap, you won’t get thick foam, but if you use too much, you may clog the foam gun.

Next, attach the bottle to your foam gun and check the nozzle and sprayer attachments to ensure they are firmly connected. You can then begin spraying your vehicle from the top down to coat it with foam. Gently wipe down your car with a microfiber or wash mitt, and then disconnect the foam gun body from your sprayer to rinse with clear water.

Gently wipe the surface of your vehicle with a clean, dry microfiber towel to absorb the rinse water and prevent spots or streaks.

Which is best for you? 

Both foam cannons and foam guns will provide ample suds for routine car cleaning. Foam cannons provide pressurized cleaning strength and produce thicker foam, but foam guns are much more convenient to use with just your garden hose. Either tool creates lubrication to make your car wash faster, safer, and more effective. While not a detailing essential, foam cannons and foam guns are helpful tools that offer a satisfying car washing experience. If you have the chance, give one a try, and as always, enjoy the ride! 

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