Pressure washers come in varying strengths intended for various uses. The PSI rating shows the pounds per square inch which your machine pushes out. All pressure washers will come rated for a maximum PSI while the operating pressure can be quite different.
The type and number of nozzles that you use also changes the preferred use of your washer, at times dispersing the pressure of a machine so much that it becomes safe for washing cars.
You’ll find that each pressure washer has a PSI rating (pressure) and a GPM (gallons per minute) rating which refers to the maximum water flow. Here we’ll be showing you how to determine which ratings you need to look for when buying a high-pressure cleaner for washing your car.
Have you ever thought about starting your own small business?
Check out our super-detailed guide on how to start a pressure washing business.
Find the Amplified Water Pressure
The easiest way to make a comparison between various pressure washers is to determine its amplified water pressure. Multiply the PSI by the GPM to find the maximum cleaning power of your pressure washer. While other factors should be considered as well, such as the make, nozzles, and afford-ability, this at least gives you a starting reference.
When you’re using a high-pressure washer on a vehicle with scratches then you need to take extra care. If the water from your washer manages to get under the paint it’ll lift it off. Either avoid damaged areas completely or first test from a foot or two away to gauge whether it’s safe. A similar approach should be taken to dents. Spray from at least a foot away to ensure that you don’t worsen any dings or dents.
What Pressure to Expect
Car washing is made quick and easy using pressures ranging from 1400 to 2100 PSI. Higher power is seldom ever needed. Pressure washers for home use typically feature a GPM of 1.5, while the higher the speed the better, helping for both the standard pressure wash and its foam attachments. The average accepted minimum pressure is 1400 PSI for most, which allows you to wash away all stubborn grime and debris without the need for brushing at all.
Pressure washers typically advertise their top-end pressure while having a different working pressure. You must always make sure that your working pressure exceeds 1400 PSI or you lose a lot of the convenience otherwise provided by a good pressure wash. Most good quality 2100 PSI pressure washers feature a GPM of between 1.8 and 1.9 and have a working pressure rating of 1450 PSI.
While it is possible to clean your car with a low powered pressure washer such as a 900 PSI, the results are ineffective. It is only from 1400 PSI upward that a high-pressure washer begins to make a significant impact. Lowered powered electric models are typically of shoddy manufacturing and carry poor durability and power to match.
If you want to be as safe as possible then start with a 25° nozzle. This provides the least pressure from which you can adjust your distance, the pressure, and the nozzle angle. Most find that when using a moderate pressure such as 1400 to 1500 PSI, a 30° to 40° nozzle works best.
Another great option is a foam cannon. This attachment can truly harness the higher PSI power of larger units covering your car in a dense, penetrating foam which gets rid of all grime and dirt in just a few minutes. All that’s left is a quick rinse with a wider dispersion of water after allowing the foam to sit for a few minutes. A foam cannon is highly recommended if your high-pressure washer doesn’t already have one.
Safety Considerations for Your Car Wash
When you have the right nozzle with the right amount of pressure and the right cleaning agents, you can rest assured that your car will be cleaned better than ever without any chance of damage. A great way to test the pressure is to spray the ground from three to four feet away, moving closer to get a feel for how strong it is. This’ll let you determine the safest distance to wash your car from without risking damage.
Always point the nozzle of your pressure washer towards the ground and you’re guaranteed an even clean while never risking chipping any existing dings neither. Most high-pressure washer owners recommend that you pre-soak your vehicle before going over it with one of the more intense nozzles. This prevents any dirt, dust or debris from scratching your paintwork once they get hit with a high-powered blast.