Basics: The Prep Wash
By Prentice St. Clair

Automotive detailing can be described as the cleaning and protection of the vehicle's surfaces. So the first part of any detail is cleaning. As far as the vehicle exterior is concerned, the initial cleaning step is the prep wash. This month, I would like to discuss some of the distinct issues surrounding this seemingly simple step in the complete detailing of a vehicle.

DEFINITION
The purpose of the prep wash is simply to prepare the vehicle exterior for detailing by removing excess surface dirt and grime. A common misconception is that the prep wash must remove every last spec of grime, staining, and surface contamination from the vehicle. In fact, the prep wash will not remove
all stains and surface contamination but will get most of the loose stuff off so as to clear the way for the use of other detailing chemicals that can remove remaining contamination.

The exact procedure that you use to prep wash a vehicle depends upon many factors, including how dirty the vehicle is upon arrival, the configuration of the prep wash area, and the equipment and chemicals that you are using. Ultimately, you will develop a prep wash procedure that is the most efficient and effective for your situation. Even if you have been detailing for some time, my hope is that you will pick up from this discussion a couple of ideas that will help you improve your prep wash procedure.

PREP WASH AREA
If at all possible, the prep wash should be conducted in a dedicated area. It's awfully difficult to conduct the remainder of the detail in an area that contains the water, dirt, and grime run-off from the prep wash. A higher volume detail operation can have dedicated equipment, chemicals, and technicians in the prep wash area. This type of approach tends to be very efficient, given that it is accomplished with clear standard operating procedures performed by trained technicians.

If your detail operation is part of an automatic car wash, your prep wash is simple - just run it through the tunnel. You may need to spend some time (pre-tunnel) applying extra cleaning agents to the front grill, wheels, and wheel wells, but you are still the envy of those of us who must prep wash cars by hand.
Be aware also that the automatic car wash typically does not remove as much of the surface contamination as a thorough hand wash does. So you may have to spend a bit of extra time during detailing to make sure that the surfaces are clean. Moreover, some technicians prefer to hand wash vehicles being prepared for detailing, despite the existence of an on-site car wash. Still another approach is to wash the dirtiest parts of the vehicle, like the engine bay, wheel wells and wheels, and doorjambs first with a pressure washer, then run the vehicle through the automatic car wash.

PREP WASH PROCEDURE
A common mantra among the motoring public is that a vehicle should be washed "from top to bottom." For the professional detailer performing a prep wash, however, the mantra should be "wash the dirtiest parts first." As the dirty areas are blasted clean, some of that dirt and grime coming off of these areas will splash onto the "cleaner" areas, so it makes sense to wash the cleaner areas last.

Most agree that the prep wash begins with an initial vehicle rinse-off. However, if you are not working in the sun and the vehicle is not very dirty to begin with, you can save some time and water by starting the prep wash without an initial rinse. At the other extreme, if the vehicle is coated with mud, the initial rinse is quite important as a means to remove as much of the surface mud and dirt as possible before continuing with the prep wash.

If the detail job at hand includes work in the engine bay, wash the engine first. As you clean the engine, moisture from the pressure washer as well as oil and grime will spit onto the remainder of the vehicle. So it makes sense to get this done before proceeding with the prep wash.

The first place to wash (after the engine bay) is the doorjamb area. Most professionals agree that even the most basic exterior detail includes cleaning the doorjambs. Spray the hinge areas with degreaser and rinse them off. If you are concerned about splashing into the interior of the vehicle (especially if the interior is not to be detailed), you can rinse the doorjambs by closing the door and pointing your pressure washer at the door seams. The remainder of the doorjamb can be cleaned with multi-purpose cleaner and a soft brush and then rinsed.

Next, it's time to clean what I like to call the "lower third" of the vehicle. This includes the front grill, light groups, bumper and spoiler; wheels, tires, and wheel wells; doors and sides from the trim line down (or approximately the bottom third) and the rocker panels; and the rear light groups, license plate area, and bumper. In some higher-production operations, cleaning the lower third means simply spraying all the mentioned areas with a strong multi-purpose cleaner and immediately blasting the areas off with a pressure washer.

For retail and high-end detailing, I believe that cleaning the lower third areas requires agitation before rinsing. There are some great soft brushes and special sponges that are perfect for this work. Work with one area at a time (e.g., the front end or one wheel area). Spray the area with your favorite multi-purpose cleaner and then agitate it with a soft brush or scrub sponge. If you are working in the sun, you need to rinse the area right away. If not, you can wait until you have circled the vehicle and then rinse all of the lower area at one time.

After the lower third is cleaned and rinsed, rinse the top and then wash it using car wash shampoo and a wash mitt. Utilize a good, stable step stool for larger vehicles and a soft truck brush with a telescoping handle. Then rinse the vehicle thoroughly. At this point, you can use detailer's clay and a new batch of car wash shampoo to remove minor surface contamination. If the vehicle has extensive paint overspray or ferrous oxide deposits, perform the clay step separately after the vehicle is dry.

Dry the vehicle with a chamois, squeegee, a large microfiber towel, or a combination of these. Then blow out the seams and crevices with compressed air (not greater than 60 psi, please!). The vehicle is now ready for further exterior detailing.

A standard prep wash on a four-door sedan should take one technician about 30 minutes to complete, from first rinse to final dry.

PREP WASH ISSUES
Water Reclamation - One of the major issues that comes along with prep washing is water reclamation. According to the Clean Water Act of the early 1970s, it is illegal to allow any water or chemical (other than rain run-off) to enter storm drains or naturally occurring waterways. The confusion over this national regulation has resulted from the fact that enforcement of the regulation was left up to local municipalities. Thus, in some areas - for decades - nothing has been done about enforcing the Clean Water Act.
If you are concerned about increasing pressure from local enforcement of the Clean Water Act and you do not have adequate water reclamation equipment, think outside the box a bit. Consider
accomplishing your prep wash at a nearby automatic or self-serve car wash. Driving the vehicle to the car wash, having it washed, and then returning to your operation may end up consuming the same amount of time as it would have to perform the prep wash at your own site, assuming the car wash is within a few miles. You may even be able to work out a volume discount with the owner of the car wash. By prep washing your vehicles this way, you avoid all of the hassle of water supply and water run-off at your site.

Full-Service Washing - The prep wash should be distinguished from the "full-service wash." A full-service wash simply cleans the vehicle with results similar to that of a car wash. Many of the stronger chemicals used in the prep wash will not be used for a full-service wash because these stronger chemicals can strip away the protective chemicals (like waxes and sealants) that may be on the vehicle.

Pressure Washers - Most technicians agree that using a pressure washer during the prep wash is critical. Pressure washers generally use less water than a standard garden hose and also help with the cleaning of the vehicle because the water hitting the vehicle surface has dirt-lifting force behind it. It is not absolutely necessary to have a pressure washer, however, especially if you are performing only high-end extensive detailing. On the other hand, a pressure washer is quite important for engine cleaning and for high-volume vehicle washing.

If you use a standard garden hose for washing, obtain a high-quality multi-pattern nozzle, which will reduce the amount of water needed for the wash. A simple prep wash on a four-door sedan does not require more than 10 gallons of water, including the buckets of car wash shampoo.

SUMMARY
The prep wash, at first glance, seems like it should be a fairly straightforward process. But as you can see by this discussion, there are actually several issues and variables that make it a complex project. The most important thing to accomplish with regard to the prep wash is to set up standard operating procedures so that it can be accomplished in the shortest amount of time possible with the best result.

Prentice St. Clair is president of Detail in Progress, a San Diego-based automotive reconditioning consulting firm. To contact him, e-mail Prentice@DetailinProgress.com or call (619) 701-1100.