1) surface dry determination method: the surface of the dry method of blowing cotton ball and finger touch method two.

① blowing cotton ball method: the surface of the coating gently put a cotton cotton balls, with the mouth from the cotton ball 100 ~ 150mm along the horizontal direction blowing cotton balls, such as blowing away, the coating surface without leaving cotton wire, Which means that the coating has been dry, write down the time.

② refers to the touch: touch the skin with your fingers touch the surface, feel a little sticky, but no paint on the fingers, that is, the coating has been dry.

2) dry test method: hard work can be divided into pressure filter paper method, pressure cotton ball and knife knife method.

① filter paper method: in the coating surface put a qualitative filter paper (smooth contact with the coating), filter paper gently put on the dry test device, while starting the stopwatch 30s, remove the dry test device, the coating turned down, such as Filter paper can fall freely, or in the back with your fingers tapping a few times, the filter can be free to fall and no sticky paper fiber, which means that the coating has been hard, write down the time.

② pressure cotton ball method: in the coating surface put a cotton cotton cotton balls, gently placed on the cotton ball dry test device, while starting stopwatch 30s, remove the dryer and cotton balls, standing for 5min, observe the film without cotton balls Traces and loss of light phenomenon, that the coating has been hard.

③ knife knife method: with the inserts on the film at the interval between the cutting, observe the bottom layer and the film without adhesion phenomenon, which means that the coating has been hard.

Drying time measurement method In addition to the above several commonly used methods, but also the use of instrumentation, such as falling sand method, circle method and gear method, and can automatically record the drying time.