Sandability refers to the difficulty of producing a smooth and matte surface after the paint film or putty layer is dry-grinded or wet-grinded with abrasive materials such as sandpaper or pumice. It has an impact on construction quality and efficiency, especially for primers and putties and is an important performance indicator.
1. Scope and Description
This method is suitable for the determination of the sandability of primers and putty films. This method can use instruments or manual methods to polish the surface of the paint film. After the primer and putty samples to be tested have been polished for a certain number of times, the surface phenomenon of the primer and putty can be evaluated according to the load and pull, the number of times of grinding and the degree of wear. abrasiveness.
2. Apparatus and Materials
Water sandpaper; the sandability Tester is shown in Figure 1-22. This instrument is a device used to evaluate sandability of primers and putties. By grinding the sample back and forth, Figure 1-22. The number of times can be directly read by the counter, and evaluated by the surface phenomenon of the coating film.
3. Measurement method
Put the water sandpaper specified in the product standard on the grinding head of the sandability Tester, place the sample to be ground in the center of the suction cup, and observe the surface phenomenon of the sample after the grinding head is reciprocated for a certain number of times. When grinding the putty film, the load specified in the product standard should be added to the grinding head of the instrument. When grinding by hand, rub evenly on the template with water sandpaper, which can . When grinding by hand, attention should be paid to the uniformity of force and grinding speed.
4. Results presentation
Among the three samples, two samples with similar phenomena are used to evaluate the results. Judging whether the surface is uniform, smooth and matte, whether there are particles that cannot be worn off or become soft due to heat. Qualified or not according to product standards.
5. Reference standards
National standard GB/T 1770-2008.
