Finger pressure method and cotton ball blowing method are commonly used to evaluate the drying time of coating or liquid surface. Their differences are mainly reflected in the test principle and operation mode:

Finger pressure method:

Digital pressure method is to evaluate the dry time by finger finger pressure coating or liquid surface, feel whether it is still sticky or adhesive feeling. When the coating or liquid surface has no obvious viscosity or adhesion sensation, the surface can be considered to be dry. This method mainly relies on people’s sense of touch and experience, and belongs to subjective evaluation method.

The difference of drying time between finger pressure method and cotton ball blowing method

Cotton ball blowing method:

The cotton ball blowing method is to use a blowing tool (such as a blowing pump) to blow air to the surface of the coating or liquid, and observe whether there is adhesion on the surface of the cotton ball to evaluate the drying time. When there is no more adhesion on the surface of the cotton ball, the surface can be considered dry. This method is more objective than the shiatsu method and relies on observation and judgment.

The difference between the two methods mainly lies in the difference of test principle and operation mode. The acupressure method is mainly based on touch and experience. It needs to judge the dryness of the surface through the feeling of the fingers. The rule of blowing cotton balls is more objective by observing the adhesion of the surface of cotton balls. Both of these methods are relatively simple and fast methods for assessing surface dryness, but they are not accurate measurements. They can only provide a general estimate of drying time, which is also affected by a variety of factors, such as coating type, ambient temperature, humidity, etc. For some applications that require high drying time, it may be necessary to use more accurate measurement methods and instruments for the evaluation of table drying time.