Using dawn to prep the cars

[tw1012]

I have been told on this forum that this is a bad idea. Why is that?

We have been using a car wash pre wash product for the last week buy my manager is telling me that he wants to go back to using dawn. He says it cleans the cars better, that it lasts longer in the buckets because it pushes the dirt to the bottom of the bin.

What is so bad about it that does not get rinsed off in the wash with 2 high pressure cycles and 2-3 spot free cycles. Is there a damaging effect to the paint that survives even after all these rinse cycles?

thanks.

Trevor

 

[MEP001]

I have been told on this forum that this is a bad idea. Why is that?

It strips the protectants from the car's finish.

 

[jfmoran]

Car washing is a balance of chemistry. Car wash soap is typically PH neutral. Dawn dish Detergent is a fairly Alkaline product and also contains Ethanol. While the Alkalinity is good for cleaning the paint the Ethanol with repeated uses will strip wax from the vehicle and can have the effect of drying out rubber seals and gaskets as well as affecting non-painted plastic. Professional car washing usually uses metering methods to put alkaline or acidic chemicals on a vehicle so as to control cost as well as dilution ratios so that no damage occurs to the vehicle surface from chemicals being too strong or that proper cleaning doesn't occur from chemicals being too weak.

Dawn is typically a Do-It-Yourselfer product that weekend warriors use to wash their cars in their driveways. Do you think your customers would be impressed with your professional car wash were they to know that you were using a common household dish detergent to prep their vehicles?

 

[rph9168]

Dawn and other dishwashing detergents are formulated to remove organic soils like grease from food. Carwashing detergents are formulated to remove inorganic soils like road film and other environmental contaminants. Since many waxes and other protectants contain organic materials dishwashing liquids tend to strip away protection and many even dull the finish. Some body shops use dishwashing liquids on a vehicle before they prep them for painting. That alone should be a good indication on why it should not be used as a car wash prep product.

 

[Earl Weiss]

When I was a Kid I flashed the paint on a dark car that was hot and I dumped dishwasher soapy water on it.

I don't know if todays paints might have the same possible issues.

Took a lot of waxing to get it to look decent.

 

[MEP001]

Not so much with modern finishes that are almost all clear coated, but I'll bet one of the matte finishes like Mercedes does would be instantly destroyed.