You can easily avoid damaging your car (while using a heavy-duty pressure washer) by using the correct nozzle and holding the spray enough distance from the surface. A little trick is to remember moving 2x further away will 1/2 the force the surface feels (with exception of red-tip nozzle which maintains its force because it doesn’t fan the water out).
Here’s exactly what to do to avoid damaging your car while pressure washing it with a heavy-duty 3,000 PSI washer:
1. Use a 25-degree nozzle.
- If you keep the end of the pressure washer wand/lance about 1 meter (3 feet and 3 inches) from your car the effective pressure on the car will only be 3x that of a garden hose when compared to the garden hose spray being really close to the car.
- That be the right combination of cleaning power and damage avoidance when washing your car.
2. Be extra careful around fragile parts of the car like the mirrors.
- Use your instinct and back away even further if you feel you may damage bumper sticker or the mirror or other fragile parts of your car.
3. Learn the double distance half pressure rule
- Let’s say you’re using the 25-degree nozzle from 1-foot away with a 3000 PSI pressure washer. The surface that is 1-foot away feels 564 lbs because the 3,000 lbs/in2 is now spread over a larger area.
- If you move 2-feet away that becomes 282 lbs, double the distance half the force.
- Keep this in mind when pressure washing in the future!
Hope this helps.