If you need to spray paint automobile plastic parts, it is recommended to go to a professional 4S shop or local repair shop for the operation. Here are the detailed steps for plastic spray painting:
1. Stress relief treatment: Since the plastic may generate internal stress during the molding process, these stresses may cause cracking after painting. In order to solve this problem, annealing treatment can be performed, heating the ABS plastic parts to 60°C (this temperature is lower than its heat distortion temperature) and keeping it for 2 hours. However, considering that this method requires a large investment in equipment, you can also choose to use a special solution to treat the surface of the plastic part at room temperature. The treatment time is about 15-20 minutes to achieve the effect of eliminating internal stress.
2. Clean and degrease: Oil, hand sweat and release agents are often attached to plastic surfaces. These contaminants will reduce the adhesion of the paint and may cause cracking, blistering or peeling of the coating. Therefore, thorough cleaning is necessary before painting. Initial cleaning can usually be done using gasoline or alcohol, followed by chemical degreasing. After chemical degreasing is completed, the residual alkali solution on the surface of the workpiece should be thoroughly rinsed, and purified water should be used for final cleaning, and then dried or otherwise dried.
3. Eliminate static electricity and remove dust: Since plastic products are insulators, their surface resistance is very high, so static electricity is easily generated. Once charged, it is easy to absorb tiny dust in the air. The dust attached due to static electricity is difficult to blow away with ordinary methods, but high-pressure ionized air flow can be used to eliminate static electricity and remove dust at the same time.
4. Painting: The standard thickness of plastic coating is 15-20 microns, which usually requires 2-3 sprays to achieve. After each application, allow the coating to dry for approximately 15 minutes before applying the next application. If you need a shinier surface, you can also spray a layer of clear paint. It is worth noting that this coating method has almost no impact on the flame retardant properties of plastic parts.
5. Drying: After spraying, you can choose to let the coating dry naturally at room temperature, or bake it in an oven at 60°C for 30 minutes to speed up the drying process.
