When choosing sandpaper, the fineness of the final grit significantly impacts polishing time and the final result. Generally, finer sandpaper shortens polishing time and improves sample quality. However, individual usage habits and techniques vary, so selecting the right sandpaper requires considerable practice and experimentation.
For 20 steel, industrial pure iron, and ductile cast iron, the following grit sizes are recommended: 180 (240) 320 (400) 600 800 1000 1200
For 20 steel, although theoretically 1500 and 2000 grit sandpaper can achieve better results, 1200 grit sandpaper is usually sufficient to produce excellent samples.
Industrial pure iron is more difficult to polish, and fine scratches are harder to remove, so using 1500 or 2000 grit sandpaper is recommended.
Scratches on ductile cast iron are generally easy to remove, and polishing time is shorter. Therefore, the choice of sandpaper has less impact on the final result; simply find the sandpaper that works best for you.
Through continuous practice and experimentation, you can find the most suitable sandpaper combination to improve polishing efficiency and quality.
