There is a big debate that goes on when detailers speak of what chemical to use when hand washing cars. Some purists follow the principle of using chemicals for what they were formulated to do. Carwash shampoo to wash the car; engine degreaser to degrease and clean engines; carpet shampoo for the carpet, and so on. Others believe if a chemical works, use it. So, they use degreasers at different dilutions for engines, wheels, vinyl, carpets, etc. The same with using “dishwashing” detergent to wash cars.
This article will provide you with reasons why you should not wash a car with dishwashing detergent.
Dishwashing detergent makers claim their products "soften hands while you do dishes". Others promote the ability to remove grease with one drop, while others claim that they can provide dishes with a spot-free shine. Hearing this, it is any wonder so many consumers, and unfortunately detailers; think it is safe to use dishwashing detergent to wash their automobiles.
Chemical experts however, point out that dishwashing detergents are a very poor choice for today’s clear coat finishes. Not only should detailers not use dishwashing detergents, they should inform their current customers of the harm these detergents can do, to not only the paint, but they can also strip off wax protection that they just paid for.
This article will provide you with the information you need to educate your customers to use your services or a professional product to wash their vehicles instead of in the driveway.
Carwash Shampoo vs. Dishwashing Detergent
The following are seven reasons why washing cars with dishwashing detergent is dangerous to a vehicle's finish.
Reason #1: Water Softeners
Dishwashing Detergent: Manufacturers of dishwashing detergents assume dishes will be hand dried therefore; many dishwashing detergents do not contain water softeners that will prevent spotting.
Using dishwashing detergent on an automobile increases the likelihood of water spotting.
Carwash Shampoo: Most car washing products contain ingredients that soften the water, which helps prevent water spotting.
Reason #2: Grease Cutters
Dishwashing Detergent: Dishwashing detergents are generally made with certain surfactants which are designed for grease cutting and removal. However, these surfactants can strip off silicones and waxes on a vehicle’s surface.
The surfactants will also strip any protection on bare metal parts of the vehicle, such as the engine compartment or areas inside the doors. This can promote rusting when the detergent finds its way into these areas. As well, any chipped spots on the paint are susceptible to corrosion.
The end result is a dull, unprotected finish, and the possibility of corrosion in undetected places.
Carwash Shampoo: Carwash shampoos are formulated with surfactants that are gentler to the car's surface in that they do not strip the car of wax or sealant protectants applied to maintain a glossy and protected finish.
Reason #3: Emollients
Dishwashing Detergent: Dishwashing detergents often contain what are called, cosmetic chemicals (emollients) to keep hands soft and prevent the cracking and drying that can occur when immersed in water for too long.
These emollients will make a vehicle finish difficult to dry and/or leave it with a smeary appearance and dull finish.
Carwash Shampoo: Carwash shampoos do not contain emollients or anything that would be a cosmetic “perk”.
Reason #4: Surfactants
Dishwashing Detergent: The surfactants in dishwashing detergent can produce foam that is thicker, denser, and often will not rinse as well as traditional carwash shampoos. Certainly a problem when washing a car.
Because dishwashing detergents may not completely rinse off, the vehicle may end up with water spotting or a smeared finish.
Carwash Shampoo: The surfactants added in carwash shampoos, give a thicker, stronger appearance to the product, since “no foam” is often misconstrued as a weak shampoo. However, the surfactants used in carwash shampoos are not the same as surfactants used in dishwashing detergent and will rinse easier.
Reason #5: Dirt Removal
Dishwashing Detergent: For the most part, the surfactants used in dishwashing detergents are not the same as those used in a carwash shampoos, as mentioned above. Surfactants used to remove food residue and grease from pots, pans, and plates are not the most effective surfactants to remove dirt and oil film from a vehicle. The surfactants used in dishwashing detergents can leave dirt and oil film behind, causing you to work harder having to wash the vehicle more than once.
Carwash Shampoo: The surfactants used are specially formulated to remove both dirt and oil film.
Reason #6: Additives
Dishwashing Detergent: Dishwashing detergents contain no special additives.
Carwash Shampoo: Well-formulated carwash shampoos contain special additives that provide benefits for hand car washing. For example, a small amount of high pH additive helps to more effectively remove the dirt and road film and to neutralize any acid rain spots on the vehicle. These additives are not contained in dishwashing detergents.
Reason # 7: Table Salt
Dishwashing Detergent: Sodium chloride (table salt) is commonly used as a thickening agent in dishwashing detergents to give them the appearance of a quality product.
Washing a car with dishwashing detergent is literally like using salt water. This can result in severe water spotting and promotion of corrosion.
Carwash Shampoo: A good quality carwash shampoo will not contain salt to thicken the product.
Summary
There are many detailers who will disagree with this article and contend that dishwashing detergent works fine for them to wash cars. That said, why not then use liquid laundry detergent to bathe in, or use dishwashing detergent to wash your hair? They will work, won’t they? But at what cost to your skin, scalp, hair?
