Written By Steven Craig

ARTIST PROFILE

STEVEN CRAIG

DATA

Steven Craig is the owner and head painter of SKC CUSTOMZ in Lake Havasu City, AZ. In the past Steven has won the House of Kolor Prestigious Painter Award and was a 1st Place winner of Dupont's Hot Hues Awards. He most  recently was awarded the Matrix System's FX Grand Prize Award. Steve paints a wide range
of jobs from guitars to large off shore boats. Visit  his web site at

Airbrush : Iwata HP-BH, Custom Micron B
Spray Guns: Iwata LPH400 ,Iwata LPH300, Iwata LPH-80
Paint Media: PPG, Xotic Colours, Dupont and Matrix Systems
Surface Media: Everything I can get paint to stick to.
Masking : R-Tape and 3M Masking Tapes
Projector: Artograph
Lighting : Natural and Florescent. Spray-Line and Spray King Paint Booths
Steven is a Certified Paint Technician for both PPG and Dupont Industries.

"Plastic Prep"

Cleaning The Plastic: 
 This is very important to do and is a multi-step process. Start by cleaning with soap and water. The soap should be a pH-neutral automotive soap to avoid contaminants found in other types of soaps. Use hot water, this will help dissolve the water soluble contaminants. The next step is to clean the plastic with isopropyl alcohol, which will remove any non-water-soluble mold release agents.

Sanding:
 Heavy grit sandpapers are not recommended. Sandpaper is far too agressive and will create deep grooves in the substrate. While thorough sanding is essential, the choice of abrasive is critical. The best method is to use a gray abrasive pad with sanding paste (PPG DX101). Apply a small amount of paste and add a few drops of water. The water will help lubricate the gray abrasive pad and make it last longer.

 Scuff the entire substrate and add sanding paste as needed. Try to maintain the same direction, back and forth while scuffing. By scuffing the surface wet with sanding paste, the plastic will not take on a static charge during the scuffing process. If needed, fold the scuff pad in half to get into hard to reach areas.

 Dry the substrate and inspect it for areas that appear to have a shine. Any shine or gloss remaining indicates an areas that has not been properly scuffed. Repeat the scuffing process until all the shine is gone. After the part has been completely scuffed, it should be rinsed and dried. The dry surface of the part should have a clean and uniformly dull sheen. The water should stream off the substrate  when rinsed. If the water beads, there is still mold release agents on the surface. Continue scuffing with paste until there are no remaining water beads.

 Once the scuffing process is completed, wash and dry the substrate. For the next step, we are going to use PPG's "OneChoice" Plastic Adhesion Promoter" system. Begin with the Clean and Scuff Sponge (SU4901).  The Sponge is pre-saturated with a cleaning solution, specifically designed to lightly abrade the plastic part, removes contamination and helps pull out any remaining mold agent. 

 The cleaning solution is the key to this step. I recommend having a few of the Clean and Scuff pads ready for use. Turn the sponge so the abrasive side faces the substrate. Scrub the entire surface and work on the cleaning solution into the plastic. Concentrate on working the cleaning solution into hard the reach areas. Rinse with water, then blow off or wipe dry.

  Plastic easily takes on a static charge and plastic parts with a static charge attract dust, so an anti-static agent should be used.
 Apply the solution that is on the adhesion cloth by wiping in one direction over the entire substrate. You want to achieve a light coat of solution on the surface. Do not wipe the solution off. Let the it dry (flash) for 3-5 minutes. When it's dry, it should appear to have a film over the substrate.

 Immediately after completing the Clean and Scuff process, rinse off the substrate with water and dry. Use compressed air to speed up the drying time. Once the substrate is dry, wipe the surface down with a Wax & Grease Remover (PPG DX330) to remove other non-mold release agent contaminants. Do not let the Wax & Grease Remover dry on the surface, continue wiping with a clean cloth until it is dry.

 The Advanced Plastic Bond penetrates areas where the wipe can't get. The plastic bond is also an agressive adhesion promoter. When applying, spray in light coats. You can almost just mist it on. Allow 3-5 minutes for the solution to flash.

 OneChoice Plastic Adhesion Promoter system in comprised of three steps. Step two is using the Plastic Adhesion Wipe (SU4902). The pre-saturated wipe is formulated with PPG's NanoAdhesion technology, designed to apply advanced film-forming adhesive and anti-static material to unprimed plastic in a single step.  

 The final step in the OneChoice system is the Advanced Plastic Bond, either SUA4903 (Aerosol) Advanced Plastic Bond, or SU4903, a ready-to-spray product. Both provide superior chemical adhesion to all common unprimed plastic substrates. Pour the Plastic Bond directly into a spray gun. What is not used can be put back in it's original container for later use.

 Once the Plastic Bond has flashed, t he plastic part is now ready for priming or sealing. Once your primer/sealer has been given its required flash time, you're ready to paint!

 Flex Additives can be added to the primer/sealer and top coats but there has been much debate lately on if they are even required. The safest recommendation regarding flex agents is that all paint manufacturers' recommendations should be followed.

 Follow this process and you should have no problems with painting on most common plastics. The job you see in the photo above can attest to how well this system works. I was very abusive to the paint on this job, it has been ground with an angle grinder to create a spun metal effect, was taped on multiple times and razor blades were used to cut masking on top of it. Not once did I have paint delaminate while working on it. Now that you know how to paint plastic, nothing is safe from being customized.

 Custom Painters have been fighting plastics for years. Obtaining a good adhesion to plastics without delamination issues was extremely difficult to accomplish. This was mainly due to different types of plastics. The availability of proper adhesion promoters was almost non existent. Most custom painters are at a disadvantage because they learn through trial-and-error. I highly recommend that a person who is serious about a career in the custom paint field to take a Manufacturers Certification class. There you will learn about products and procedures, all of which are rapidly changing. 
 Plastic parts have a mold release agent mixed in with them. Mold release agents are lubricants that are injected with the plastic to help extract the part from the molding dies. Because these agents are mixed with the plastic during manufacturing, they cover the entire surface of the part, inside and out. To remove these agents, the initial cleaning is an important step prior to painting. 
 There is an array of plastics used in manufacturing. The two main categories of plastics used are Thermoplastic, a type of plastic that will soften when heated, and Thermoset, which after it hardens or cures, will not soften when heated.  Parts also can be made from many different compounds such as Thermoplastic Olefin (TPO), Polyurethane (TPUR), Acrylonitrilebutadiene-Styrene (ABS), Sheet Moldable Compound (SMC) or Fiber Reinforced Plastic (FRP), just to name a few.
 Most of the adhesion promoters were designed for specific plastics. Recently, many of the leading paint manufactures have developed lines of improved plastic adhesion promoters. PPG has made available their "One Choice" which is a single system that was designed to cover most of the plastics on the market.

Getting Paint To Stick To Plastics