Prepare for custom paint work with cutting-edge directions

June 1, 2017
Before getting started, you’ll need to brush up on your custom paint skills, including prep work. Every great paint job begins with proper prep.

With the constant entry of new technology and need for attention to the smallest details in a variety of repairs, the last thing most shops need is one more departure from the ordinary. Or do they? If a shop has the staffing, space, equipment and desire, one such avenue you could consider is custom painting. There are four good reasons why:

  1. Spark excitement. Over time, even the most dedicated employees get bored. Custom work lets you recharge their interests with creative challenges.
  2. Build your bank. Custom work can give a nice boost to shop profits — if properly scheduled among other customer repairs — and catch the attention of a new line of customers.
  3. Join a movement. Plenty of anecdotal evidence points to an influx of custom requests to traditional shops. Jason Haskin, a technical rep for Valspar’s House of Kolor, reports he now answers as many inquiries from shops as DIYers. Every national paint manufacturer offers a custom paint line. At last year’s SEMA Exhibition, AkzoNobel announced plans to partner with custom shop owner and TV celebrity Dave Kindig to create a new custom paint line.
  4. Just because. Your shop probably already has in place much of the skillset and tools to perform custom work. Giving custom paint a try is a terrific way to market your talents with show cars and other creations that your competitors are churning out. While no shop should be simply tossing away valuable time and resources, custom painting is an affordable side offering with some very big potential benefits, as long as the collision production lost is outweighed by the value of custom work.
(Photo courtesy of Ford media) Custom paint work appears to be growing in popularity for repair shops. Prepare for the day when a happy repair customer asks if your shop creates specialty finishes.

Before getting started, you’ll need to brush up on your custom paint skills, including prep work. Every great paint job begins with proper prep. In the case of custom painting, prep work needs raised to a whole new level. Use these suggestions provided by the professionals who manufacture the custom products.

Philosophical foundations

“The goal of collision repair is to get the vehicle back to pre-accident condition and back on the road, while the goal of custom work is often aesthetic,” says Axalta Business Account Manager Gene Fenske. “Custom painters will usually use higher end materials designed for appearance and spend many more hours laboring over fine details.”

That, in a nutshell, is the difference between collision and custom work. In both cases, you want to produce excellent work. But with a custom job, shops need to raise their game a notch or two (or three) to create an eye-popping product that’s going to awe a demanding customer paying a premium out of pocket price for a premium service. Creating such a product starts with premium prep work builds a foundation for excellence by sticking to strict guidelines.

 “If I was going to spend thousands of dollars on a custom vehicle, I would not take any shortcuts, especially on the surface preparation step,” says Sherwin-Williams Automotive Finishes Project Manager Nick Dowling.

(Photo courtesy of Sherwin-Williams Automotive Finishes) Plenty of veteran painters can benefit from paint manufacturer resources that grow knowledge and upgrade skills.

Providing top of the line preparation goes well beyond aesthetics. It's necessary when performing custom work.

"Custom painting also comes with more risk because of amount of material used and increased film weights," says AkzoNobel Technical Manager Matt Miles. "Because of this it is extremely important that the preparation and system selection is chosen correctly and compatible with the application."

Miles adds, "When choosing the system it is important to understand the materials used need to provide the most rigid film structures as possible with compatible Thermal Glass Temperatures (TG) for overall hardness."

Keep in mind that custom paint mistakes can be particularly costly. Missteps can result in time-intensive re-dos that can significantly cut profits (or eliminate them all together).

 “Check and recheck! Clean, clean, clean! Attention to detail and being thorough can save you many extra hours of work to correct mistakes,” says Fenske.

Superlative sanding and shaping

The bulk of that attention is spent on sanding and shaping. Gaps are to be tighter and more consistent. Body lines must be made crisper and cleaner, and panels transformed to be smoother and straighter than what the factory typically delivers.

Ringbrothers, a collision repair shop in Spring Green, Wisconsin that does business with BASF, has decades of experience producing such work. Founders Jim and Mike Ring have picked up a host of industry awards for their efforts, including “Best Chevrolet of Show” at the 2014 SEMA Show and back-to-back Goodguys Street Machine of the Year awards, along with numerous magazine covers and OEM builds.

They suggest the following ultimate shaping and sanding procedures.

Step 1. Metal prep. In a climate-controlled space, use a DA sander to strip the entire vehicle down to bare metal.  For good adhesion, wipe down the car with metal cleaner before grinding with 80 and 36 grit depending on metal thickness.

Put away the DA sander and all power tools until just before the car is ready to buff.  All sanding from this point forward is done by hand.

Step 2. Skim the vehicle. Create mirror flat panels by first fully assembling the car with seals and gaskets installed. Build a stable base for the primer and clear coat by skimming every square inch of the entire car with body filler. 

To ensure the gaps along doors, hood and trunk lid do not shift during the sanding process, apply 1-1.5 in. spots of filler across the gaps around each side of the doors, hood and deck--one to two spots per side depending on length of panel.  These filler spots will remain until primer has been sanded to 600 grit.

Step 3. Tape edge lines.  To keep crisp, straight edges, grooves and/or creases, apply masking tape along the top of the edge.  Sand up to the tape edge. Remove that tape, and apply new tape to the bottom of the edge. Sand down to the tape edge. Repeat for each level of sandpaper grit described in following steps.

Step 4. Guide coat. To reduce shrinkage, use dry guide coat between each level of sanding in all sanding steps.  Guide coat will stay in any scratches or pin holes and reveal what has not been sanded or sanded well enough. 

Step 5. Sand filler. Using a sanding block, sand filler with 36 grit, 80 grit, 180 grit and 320 grit before priming.  Again, be sure to apply dry guide coat between each sanding layer. 

Step 6. Spray polyester.  Spray the vehicle with four coats of spray polyester instead of primer.  Block sand with 80 grit, 180 grit, and 320 grit, applying guide coat between each sanding layer.  If no spots have been sanded through to the filler, then finish sanding car with 400 grit and finally 600 grit. 

If there is a breakthrough to the filler, stop at grit 320 and re-prime with Primer Surfacer.  Continue block sanding with 320 grit, 400 grit and finally 600 grit. 

Step 7. Disassemble vehicle. Once 600 grit sanding is complete, cut filler gap spots and then disassemble car.  Clean up all edges, jams, etc.  Prime edges where necessary. 

(Photo courtesy of Sherwin-Williams Automotive Finishes) Plan on spending significantly more time sanding and shaping custom jobs vs. repair work.

Plastic problems

Custom prep involves many materials other than metals. With owners of a wider range of vehicles and model years requesting unique paint work, plastics have been pushed into the forefront. Plastics provide a different kind of challenge since you don’t necessarily need to strip away the existing finish. Instead, you’ll want to first check if it’s in good enough shape to use as a foundation for new paint.

PPG supplied the following directions for determining if the finish needs removed and the steps for prepping in either case.

Note: Always inspect plastic parts for imperfections and damage. Make any necessary repairs or replace before putting down the new finish.

Step 1. Wash the part with hot water and soap. Rinse and dry completely.

Step 2. Clean the entire part with an appropriate cleaner and clean towels to remove contaminants. Dry thoroughly.

Step 3. Test the existing finish by rubbing it with a strong thinner or urethane-grade solvent on a clean towel. If the coating wipes off or softens significantly, remove it by sanding and jump to Step 6. If the coating integrity is maintained, it can be used as a foundation.

Step 4. Begin prepping by block sanding with P220-P320 grit to remove minor defects. Note: The object is to remove any defects and level the surface—not to strip the surface to bare plastic.

Step 5. On edges, body lines and difficult-to-sand recessed areas, use a gray scuff pad or pad coarse enough to remove any gloss.

Step 6. Re-clean the entire part thoroughly with an appropriate cleaner and clean towels. Dry completely.

Step 7. Tack off the dry part.

Step 8. Apply plastic adhesion promoter to bare plastic or any cut-through areas.

Step 9. Apply one coat of flexible sealer to the entire used plastic part.

Note: You'll need to take similar steps when prepping fiberglass or carbon fiber check for surface porosity and use a pit filler as needed prior to priming, according to Miles.

(Photos courtesy of Sherwin-Williams Automotive Finishes) The basis of great custom prep work—clean, clean and clean some more.

Epoxy elements

For almost any kind of restoration project, epoxy primer sets the foundation for corrosion protection. As such, it sets the foundation of the entire job and must be applied correctly. Use the following tips from PPG to guide epoxy work.

  • Epoxy primer will not stop or neutralize any rust that has already started or is already present. Note that bare steel starts to rust in as little as 30 minutes at 50 percent humidity. Aluminum starts to oxidize in 8 hours after sanding.
  • Epoxy primer needs to be applied within 30 minutes of paint removal, especially in humid conditions. (If this isn’t possible, consider working on individual parts or smaller areas of the project to meet this timeframe.)
  • Untreated steel and aluminum should be coated with a minimum of 3.0 mils wet (1.5 mils dry) of primer for corrosion resistance.
  • To avoid contamination, do not touch metal with bare hands before applying primer.
  • Epoxy primers should only be sprayed over metal or aluminum that has been treated with metal treatments and within 8 hours after those treatments have dried.
  • Sand blasted or sanded metal should be epoxy primed within 30 minutes at 50 percent humidity to prevent corrosion from starting.
  • Check the application recommendations for any metal treatments. Example recommendations often require the epoxy to be coated with a minimum of 1.0 mils wet (0.75 mils dry).
  • Note that metal treatments cannot be used in some areas due to VOC or heavy metal restrictions. Refer to local regulations.
  • One coat of epoxy primer must dry 1 hour before body filler application. Two coats of epoxy primer must dry overnight before filler application.

Fantastic finish

As with any other paint department work, you don’t want to be left sort of supplies. Since custom jobs often use up more materials, be sure to keep extra on hand. Also stock up on any necessary specialty items for final prep steps and other procedures such as detailing. Dowling recommends:

  • Fineline / Pinstripe tapes
  • Liquid spray masking
  • Glamour Clearcoats
  • Dry Effects
  • Specialty Pigments/Effects
  • Dyes

Dowling and the other professionals ABRN spoke with also stressed the need for shops to continually reassess both their methods and knowledge of this field due to the regular updates to custom technology. Dowling directs customers to stay in contact with paint manufacturer reps and resources who can provide the latest advice and directions, along with critical information on the newest products.

Haskin notes the same. He says he spends a good part of his time getting veteran painters back up to speed. Haskin declares, “There’s a lot of old dogs out there needing some new tricks.”

Some new tricks could be your key to a hot business line.

About the Author

Tim Sramcik

Tim Sramcik began writing for ABRN over 20 years ago. He has produced numerous news, technical and feature articles covering virtually every aspect of the collision repair market. In 2004, the American Society of Business Publication Editors recognized his work with two awards. Srmcik also has written extensively for Motor Ageand Aftermarket Business. Connect with Sramcik on LinkedIn and see more of his work on Muck Rack. 

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