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Is Your Foam Cannon Not Working Properly? Try These 5 Tips:

Foam cannons are effective detailing tools that are used by the casual enthusiast and professional detailers alike. Not only are they effective at lubricating your vehicle’s paint, but they’re just fun to use. It’s a practical and entertaining method of starting a wash, and it’s the closest you’ll get to having a bubble bath with your beloved car or motorcycle!

That pleasant experience can disappear quickly if you aren’t seeing the type of thick foam found in YouTube videos. If your foam cannon isn’t performing the way it should, don’t panic!

Fixing a foam cannon that’s no longer working properly is more than likely a simple issue. Most of the time, watery foam will be caused by a clogged pickup tube, incorrect soap mixture/setting, or using the wrong soap. If it’s never worked well, your pressure washer might not have enough GPM or PSI.

Foam cannons vary across the marketplace and have different conditions that must be met to work properly. If you’re having issues with your foam cannon, try these solutions for common problems.

Make sure the pickup tube isn’t clogged, kinked, or damaged

Foam cannons are simple instruments with very few components. They consist of:

  • A connection that attaches to a water source (pressure washer)
  • A bottle for storing soap
  • A pickup tube that introduces the soap from the bottle into the stream of water
  • A knob on top to adjust the concentration of soap
  • An adjustable nozzle that sprays foam from the tip in a narrow or wide pattern

Many pickup tubes have mesh-like caps on the end that picks up the soap to capture any particulates that may be in the soap container from getting sprayed onto your vehicle. Check that the tube isn’t clogged or obstructed with contaminants, and make sure to thoroughly rinse out the soap container prior to use to avoid scratch-causing contaminants being flung onto your vehicle!

The pickup tube can also get kinked or detached from the foam cannon itself while still being in the soap container. Ensure it’s securely connected when you fill the bottle for a wash.  

Use the adjustment knob to make sure it’s set properly

For the most part, the knob on the top of a foam cannon is a set-it-and-forget-it adjustment. It’s not uncommon for it to get bumped while either using it, setting it up to wash your car, or putting it away when you’re done. Before you assume that there’s something wrong with your foam cannon, turn the knob back and forth all the way to make sure it’s not a silly problem like this.

Check your soap mixture – are you using enough?

Getting the right dilution ratio of soap and water is important when it comes to making thick foam. Most soap manufacturers will give you a recommended mixture on the bottle so start with that. You can adjust as necessary from there.

You may want to use more soap for an especially dirty vehicle to help loosen the debris from the paint prior to using a wash mitt. Conversely, you can save soap by turning the concentration down when a vehicle is simply dusty or needs a quick maintenance wash.

Additionally, double check that your soap-to-water ratio is conducive to the level of foam you would like for your car’s unique state of clean. As a general rule, more soap equals more foam, but there is certainly a point of diminishing returns where foam production reaches its maximum potential, regardless of how much soap you’re using.

Experiment with your foam cannon – going to the highest concentration setting may produce just as much foam as say, the mid-way setting.

Ensure your pressure washer meets the GPM requirement

Pay attention to the capabilities of your pressure washer when shopping for a foam cannon. Many foam cannons require a specific GPM (gallons per minute) rating to perform optimally. For the most part, you’re going to need at least 1,100 PSI and as close to 2 GPM as you can get (although lower is manageable).

According to Obsessed Garage, both the popular MTM Original and PF22.2 foam cannons recommend a minimum of 1.4 GPM and a maximum of 5.3 GPM in order to work properly. So if your pressure washer has less than that, it could be the reason for your weak foam.

Low powered, electric-driven pressure washers can sometimes not produce the amount of pressure needed to get the desired results. The solution is not necessarily to buy a new pressure washer – you just need the right size orifice. 1.1mm tends to work best with lower PSI units.

Stepping up to a more powerful gasoline-powered pressure washer may also require matching the correct orifice. A 1.25mm orifice tends to work best with these high-pressure units.

Try a different car wash soap

Contrary to some beliefs, not all car soaps are created the same (and you’re not still using dish soap, right?!). Some car soaps are formulated for specific purposes, such as maintaining a ceramic coating or a matte paint job, while others are designed to add a layer of wax to the vehicle or, conversely, give the paint a clean slate by removing prior coats of wax or sealants.

It makes sense then, that there are also soaps specifically formulated for use in foam cannons. These soaps create the most suds and bubbles when used with a foam cannon, so give one of these a try if you’re not already using one.

Chemical Guys’ HoneyDew Snow Foam soap is a highly rated foaming car wash, as well as Blackfire’s Foam Soap. If you’re hesitant to switch to a new soap, Blackfire offers a Foam Booster that is added to your existing car soap to help it produce more foam.

With the rise in their popularity, most soaps are considered “high foam”. But typically, those with “foam” in their names or marketing materials are the best to use in a foam cannon. The aforementioned Snow Foam soap from Chemical Guys is known to produce truly dense, snowlike foam, with layers and layers of foam heaped onto the car!


Foam cannons are a lot of fun to use while simultaneously elevating the quality of your vehicle wash experience. The more lubricating soap used on the vehicle’s surfaces means more contaminants are held away from the paint, minimizing swirls and scratches caused by improper washing techniques.

Properly matching your foam cannon to the right pressure washer can make all the difference in its performance and further, using a soap designed for cannons can create massive amounts of suds that protect your vehicle’s paint job, while making the experience more fun and satisfying.

If your foam cannon stops working the way it used to, it’s very likely that one of these simple tips will get you back on track.

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