Simple and Quick Distinction Tips

When gently bending two boards of the same thickness, if they are not easily bent and have strong rebound ability = hard board; if they can be slightly bent and slowly rebound when released = soft board;

When lightly tapping the edges, a clear and loud sound indicates a hard board; a dull and muffled sound indicates a high-adhesive soft board;

Sandpaper grinding: Hard boards produce more dust and are difficult to grind; soft boards are prone to grinding out resin strips.