The gel coat layer must be made under good environmental conditions, and the operation must be very serious. Try to construct at a temperature of 15-32°C and a relative humidity of 75% or less. The surface of the mold should be kept clean and must not be contaminated by oil, water, dust and other dirt. The gel coat surface after construction should also be clean. The main defects that may occur during the construction process are wrinkles (like grooves), pinholes, etc. Analysis of the causes of wrinkles and solutions.
The reasons for the wrinkling of the gel coat layer are:
①The gel coat layer is too thin, resulting in poor curing, and after lamination, it becomes serpentine due to the dilution and swelling effect of styrene in the resin;
②Brushing, especially spraying, is easy to cause pores in the gel coat layer, causing styrene and even resin to enter the channel, so that the uncured gel coat layer swells and then hardens, resulting in stress shrinkage;
③The styrene mist is not easy to escape at the sharp corners of the mold or in the deep mold, causing the swelling of the gel coat layer;
④Before the gel coat layer is cured, lamination construction is carried out prematurely, resulting in the formation of wrinkles after curing due to the uneven contraction force of the two layers.
Gel coat wrinkle diagram
According to the above analysis, the solution to ① and ② is to adjust the construction viscosity of the gel coat resin. Generally, the viscosity of the gel coat resin for brushing should be higher, 2.0～3.5 Pa-s; the viscosity of the gel coat resin for spraying should be small Some, 1.5～2.5Pa·s. In order to ensure the construction thickness and uniformity of the gel coat layer, the construction can be divided into two times. After the first brushing or spraying, check whether there is a place where the bottom color of the mold can be seen vaguely. Spray 1 time.
The solution to ③ is to properly ventilate the deep mold.
The solution to ④ is to ensure that the gel coat has sufficient curing time. Usually, it needs to be cured for 0.5h above 30℃; it needs to be cured for 1h at 20～30℃; it needs to be cured for 3h at 15～20℃; it needs to be cured for 12h at 10-15℃. ; The work room needs to be heated below 10°C. Otherwise, the construction period is too long and the mold is also prone to defects.