People divide the drying and curing process of paint into the following three stages according to the degree of curing:
(1) Dry to the touch (surface dry) The coating feels sticky when the finger touches it lightly, but no coating sticks to the hand;
(2) Semi-hard drying (hard drying) The coating does not feel sticky when the finger is pressed hard, and the coating film does not move;
(3) Completely dry Carve the coating film hard with fingernails, leaving no traces on the coating film.
The three processes of surface dry, hard dry and complete dry show the concept of paint drying degree, which is divided by intuitive feeling in the coating film drying process, which is very suitable for use and evaluation at the construction site. It is also used for on-site quality inspection of coatings.
In the coating operation, the curing degree of the coating film can also be refined and classified as follows:
Touch finger dry Lightly touch the film paint without fingers attached;
Dry without sticky dust Dry to the extent that it does not stick to dust;
Dry surface Dry to a state free of sticky dust;
Semi-hard drying, light pressure film coating without fingers;
Full hard dry strong pressure film paint without fingers attached;
Sand dry Dry to the point of sanding;
Completely Dry Completely dry condition without blemishes.
