Tests conducted by the University of Texas and the Technical University of Munich set out to compare methods of washing cars and determine whether hand-washing or professional washes caused the most damage to a vehicle’s finish.
In the studies, each car was to receive the equivalent of one year’s wash stress (about 25 washes) – some cars by hand washing methods, others by automatic car wash equipment.
Ultimately, researchers found that hand washing is extremely harmful to automobile finishes in comparison to professional car washes. Read on to see what specific findings that resulted from the University of Texas and the Technical University of Munich’s research.
In an attempt to compare surface disturbances, researchers found that a single home hand wash on an automobile can produce scratches that penetrate as deep as 1/10 of the total thickness of the automobile’s paint. Much of this is because the average backyard hose is not able to supply enough water along with the detergent action to avoid damaging the car’s finish.
One thing we found interesting was that the most harmful method of washing cars was found to be the special “car wash” brushes that hook on to a garden hose and are purchased from local hardware stores or automotive supply dealers.
By comparison, the surfaces of the test vehicles washed with automatic car washing equipment appeared different. Compared with the hand washed surfaces, they were remarkably smooth, with markings less than .0003mm deep – the result of evenly moving and rotating cloth pads and curtains.
The universities’ comparison tests produced results that every car owner should be aware of. Wash a car by hand or by machine, in either case, it looks immaculate right after the wash. But, these sophisticated tests suggest that looks are deceiving: automatic car washing and hand washing have completely different effects on automobile paint.