Gel coat is a colored thixotropic product developed by FRP and countertop paint dispersed by adding pigments and thixotropic agents to unsaturated polyester (UP). Gel coat plays an important role in the production of composite materials/FRP. , It not only has a decorative effect on the surface of FRP products, but also has the functions of wear resistance, aging resistance and chemical corrosion resistance. Various problems will occur in the actual use process. Now we will analyze and solve the causes of pinholes.
Gel coat pinhole diagram
The reasons for the pinholes in the gel coat layer are:
① The water vapor in the compressed air is not released before construction, and it is mixed into the gel coat resin during spraying to form pinholes in the gel coat layer;
②The construction viscosity of the gel coat resin is not suitable, and it is still difficult to completely remove the bubbles after adding the defoamer.
According to the above analysis, the solution to ① is to check whether the moisture filter in the air compression pump is intact and whether there is water in it before construction. If so, drain the water before use.
The solution to ② is to control the amount of diluent, and control the amount of diluent within a reasonable range. According to the characteristics of UP, dilute with a mixture of acetone and styrene (the ratio is 4:1), and the amount is 5% to 10 %.