Prepping in a new era

April 4, 2023
Advancements in paint technology, ADAS systems, and OEM repair procedures require a revamp in the way most shops use their prep areas.
The paint prep area of the body shop used to be a highly overlooked area that was used as a proving ground for new technicians. This was typically where the most inexperienced technicians started. Working in these “proving grounds” allowed new technicians to get some experience in many different skillsets at low risk to the shop owner or production manager. In the prep area of old, technicians were able to remove and install small parts, develop body filler-application and sanding techniques by repairing small dents, and even get hands-on painting experience by scuffing panels, mixing and spraying primer, and even jambing parts. Over the last ten years, the prep area has changed significantly. Shops that haven’t changed their processes in this area along the way are now suffering the consequences. These consequences show up in the form of poor efficiency, increased rework, employee turnover, and even violations of OEM repair procedure callouts. The good news is that the prep area can be updated with minimal investment by making some process changes and looking at this area in a new way. Let’s dive in and start by looking at how the prep area has changed over recent years.

Efficiency and technology

The first major change to hit the prep area was a demand for increased efficiency. The paint booth is commonly looked at as the main bottleneck for most shops, and that is true most of the time. Nearly every vehicle in the shop needs to go through the paint booth. The average painter can get only about four booth cycles completed in a typical day. So, if we wanted to increase efficiency, we needed to get the most out of every booth cycle and minimize downtime. To do this, the prep area needed to be transformed from an unorganized department – that sort of ran as its own miniature light duty repair shop – to a highly tuned staging and setup area that streamlines workflow to get vehicles in and out of the paint booth as quickly as possible.

The first step of this transformation was to stop jambing parts and transition to a “parts-off” method of painting. Jambing parts caused a lot of redundancies. The back sides of parts needed to be scuffed and prepped, paint had to be mixed and sprayed, the paint had to cure, and then the outsides of the parts and panels had to be prepped for final paint in the booth. In “parts-off” painting, parts are prepped inside and out and then placed on stands that allow the entire part to be painted at one time in the booth with the rest of the vehicle. This eliminated an entire process that previously needed to be done in the prep department and massively boosted efficiency while eliminating paint and masking materials waste generated from painting parts twice.

Another big transition was parts being replaced instead of repaired. New technologies used in vehicles has been a major driving force affecting this. Shops used to fix almost everything, but now panels are lighter, metal is thinner, parts are made of many different materials each requiring special repair processes and dedicated tools, and ADAS systems require some parts to be replaced instead of repaired in order for the ADAS system to function properly. This meant that a lot of the small dent fixes are no longer done in the prep area, and instead the bulk of the time is spent prepping new parts. New technology is affecting not only the vehicles themselves but also some of the paint products and processes.

Huge advancements have been made in the paint products applied to vehicles and all of the processes used for applying and curing those products. Some of the major advancements have been the introduction of high solids primers, UV primers, and accelerated curing. Let’s start with the primers themselves. The newer primers have much higher solid contents, which means they fill much faster than previous primers. This also means that they must be atomized finer and applied more meticulously than previously used primers. Primer used to be applied on the shop floor at very low air pressure to minimize overspray. The spray gun used to apply primer was typically an old dirty gun that no longer functioned well enough to spray paint in the booth. If one of these old spray guns or low air pressure methods is used with todays high solids or UV primers, the primer will fail. Higher pressure must be utilized to break up the solids and get the primer to atomize properly. The spray gun must be equipped with the proper size nozzle and function just as well as the paint guns used in the booth for applying color and clear coat. If primer was misapplied in the past, it just meant more time would be spent sanding to correct it. Now if primer is misapplied, it means there could be pinholes in the primer or uncured areas trapped underneath the surface of the primer, both of which could lead to rework after the repair process is completed.

Advancements in curing technology

Accelerated curing is another technology that is having major impacts on the prep department. Primer used to take a long time to dry after it was applied. To minimize waste, a process called batch-priming was used. All the vehicles that needed to be primed were gathered throughout the day. At the end of the day, all the vehicles were masked up, a technician would mix a large quantity of primer, and then prime all of the vehicles at one time and allow them to dry overnight. This meant that vehicles sat for a long time without being touched. If a vehicle was ready for primer at 11:30 a.m., it would just sit the rest of the day and then get primed with everything else late in the afternoon. The next morning, there would be a lot of vehicles that needed to be sanded and prepped before they were ready for paint. This method saved on primer waste, but this was severely outweighed by the loss in production from all the starts and stops and waiting for primer to be sanded the next morning. New curing technology like UV and shortwave infrared systems allow primer to be cured in minutes instead of hours, which allows for a steady flow of work all day long. Now vehicles can be primed and cured in minutes, immediately sanded, prepped, and moved into paint.

Paint has also changed significantly the last few years, which has caused paint companies to change their SOPs. In today’s shops, primer and prep processes need to be finished with much finer grades of sandpaper than ever used before. When every shop used to use solvent-based paint, it was common to finish sanding primer with P400 grade paper and prep blend panels with P600-800 grade sandpaper. When shops switch to waterborne paints,  everything needs to be finished finer, or those sand scratches will show through the paint, leading to costly rework. It is no longer just the type of paint being sprayed that determines what grade of sandpaper should be used;  the color being sprayed can also have an effect.

Finish finer

In the past, there were a few specialty vehicles that required unique preparation methods to spray certain colors, but a few years ago all that changed when Mazda released two new paint codes (46V and 46G). This changed the prep and paint departments permanently. These two colors use one of the finest ground metallics ever used in paint on mass production vehicles. The introduction of these “micro-metallics” meant that everything needed to be sanded finer than ever before. Most paint companies call for panels to be prepped with P800 grade sandpaper when applying color. These new Mazda colors have such finely ground metallics that the metallics will settle down into P800 grade scratches, leaving severely visible sand scratches in the paint job. To avoid this, most paint company SOPs now say you need to sand with P1000-1200 grade abrasives to prep panels. With these new technical colors, it is also important to sand out any orange peel texture in the panels before applying color, or this will also show up in the form of dark spots in the final paint job. To make things even more complicated, the factory clearcoat application has also changed.

The thickness of clearcoat has dropped quite a bit in cars the last few years as well. Clearcoat from the factory has better UV protection than it used to, which allows vehicle manufacturers to apply less clearcoat to save material costs while still protecting the base coat. This means extra precautions need to be taken when sanding on body lines and near the edges of blend panels. The result, once again, is SOP callouts for finer grade abrasives to prevent “burning through” the clear coat. Finer paper means sanding takes longer, but better sanding tools and processes also need to be used.

Sand cleaner

The increasing complexity of paint has led to the need for perfectly sanded and cleaned panels. This has resulted in many shops needing to use vacuum-style sanding systems. These sanding systems have many huge benefits that every shop should consider. Since these systems remove the sanding dust as a technician is sanding, it allows the technician to see if they have removed all the factory orange peel while they are sanding. Another huge benefit of these systems is that each vacuum system typically only works with one brand of DA sander. This means that every technician is sanding with the exact same tool, which leads to more uniform finishes. When I started as a technician, everyone in the shop was using different brands of sanders with different “throws” and different speeds. This meant if we all sanded a vehicle with 800-grade sandpaper, each one of us would get a different result. That variable result can be visible and very costly with the technical basecoat colors used today.

Another benefit of a vacuum sanding system is that the shop stays much cleaner. This is great for the technician, work quality, and most importantly the perception of your customers. Shops used to be very dirty places that could give customers very uneasy feelings about the work that may be coming out of that shop. Imagine how you would feel going to the doctor and finding stains all over the carpet and dust on the examination tables and instruments. You would probably leave and go to a different doctor. That is how body shops are perceived today. You are not just competing with other body shops in the very customer focused world we operate in today; you are competing and compared with every type of business that a customer goes into, from restaurants to banks. Keeping your shop as clean and customer-facing as possible ensures your shop maintains a high reputation and promotes great reviews from your customers. A clean shop with excellent equipment also helps you draw in and acquire new technicians.

Workforce development

Technician and skilled labor shortages are one of the biggest struggles a shop faces today. These struggles also affect the prep department. I talked earlier about how the prep department was previously used as a proving ground for technicians and provided a space for new technicians to develop their skills with little risk to production or to the quality of repair. That is no longer the case. As I stated earlier, most shops are no longer jambing parts in the prep department. This means that inexperienced technicians in that department are not going to get paint experience by painting the insides of doors or undersides of hoods where it is safe to make mistakes. They also need to have proper spraying techniques and skills even to apply the newer more complex primers and undercoatings. The good news is that many companies have realized this growing issue and have started short but in-depth training courses where technicians can learn very specific skill sets in short amounts of time. Most of the paint companies offer paint classes. I-CAR offers a lot of different training. Tool companies such as Betag, Car-o-Liner and Pro Spot offer classes around their equipment and estimating.  Here at 3M, we offer both body technician classes and paint and prep courses. The biggest piece of advice I can give body shop owners and managers is to invest in your workforce. This not only helps retain employees by showing them you are invested in their future, but it also helps technicians learn and bring back new processes that can increase quality and efficiency in your shop.

The prep area has become more crucial than ever to the success of the body shop

The prep area of the body shop is not what it once was. This area of the shop has become more crucial than ever to the success of the body shop. Advancements in paint technology, ADAS systems, and OEM procedure callouts require a revamp in the way most shops use their prep areas. Properly training your technicians can increase quality and efficiency. Learning how others have changed their prep procedures and incorporating those into your shop can lead to massive gains in production. Printing off and posting paint companies SOPs can save costly rework. Don’t be one of the shops that says “Well, this is the way we have always done it.” Instead, do your research, seek out the help of experts, and invest in your employees’ education and futures. This will help position you optimally within your area and set you up for future success.

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