Tips of Auto’s Topcoat Grinding

Friends who frequently use sandpaper are likely to be aware thatsanding disc pad are utilized for industrial grinding or polishing. People often use a ceramic sanding disc or sandpaper for car paint. In the process of repairing the painting work of the body, the grinding work runs through and is the ultimate guarantee of the quality of the painting. Topcoat polishing is mainly aimed at the polishing of fine defects such as particles, fibers, and pinholes on the surface of the topcoat body. The topcoat grinding is different from the middle coating or electrophoresis body grinding. Provides higher decorative properties; so the requirements for topcoat grinding are also higher than those for midcoat or electrophoretic body sanding.


This article will comprehensively describe the use and precautions of abrasive tools in the process of car refinishing. It is believed that it will help auto repair technicians to improve sheet metal spraying technology and improve the quality of repairs There are some tips for topcoat grinding below:

  1. For topcoat grinding

P1200 wet dry sandpaper, P1500# or even P2000# sandpaper should be used and soaked in water for 3~5min. The fineness of the sandpaper is higher.

  1. For small defects

Such as single particles and fibers that need to be ground, the A5 pyramid sanding disc pad (P3000) should be attached to the pneumatic sander for grinding. When grinding, the method of circular grinding is required, and the force is uniform, and no edge grinding is allowed, and no straight reciprocating grinding is allowed.

  1. For larger particles

Enameled bags and small sags, first use a scraper to smooth them out, and then polish them. The scraper should be leveled and applied evenly. Pay attention to the angle of the blade. Do not scrape too much at one time. After scraping, first use P1200# water sandpaper for grinding, and then use P2000# water sandpaper for fine grinding, and no secondary defects should appear during the grinding process.

  1. Large-area defects

Such as orange peel and pinholes are fully polished with 1000 grit wet sandpaper or P2000# waterproof sandpaper.


  1. Polishing

should be carried out for all polishing areas. The quality after polishing requires no scratches, wear marks, polishing shadows, and unclean polishing. The surface of the body after polishing needs to be smooth and clean. The polishing process needs to be evenly applied and must not leak. Throwing, shall not cause secondary defects.


Grinding is a very important operation process in each auxiliary process of automobile coating. In order to obtain a good coating quality, the surface of each coating should first be ground, the purpose is to eliminate the unevenness and defects of the primer and improve the adhesion between the coatings; secondly, the final coating should be polished. Polishing process to improve the gloss of the coating. It can be seen that the grinding process plays a very important role in the body coating.  Binic Abrasives has successfully developed and built a coated abrasives production line, realizing the large-scale production of best sanding discs . If you still have question, feel free to contact Binic – coated abrasives manufacturers,