In order to improve and beautify the surface condition of glass fiber reinforced plastic products, increase the value of the product, and ensure that the inner glass fiber reinforced plastics are not corroded by hand, extend the service life of the product, we generally make the working surface of the product A layer of resin with a high paste content added with pigment paste can be pure resin or reinforced with surface felt. This glue layer is called the gel coat layer. The quality of the gel coat layer product directly affects the external quality of the product as well as the weather resistance, water resistance and chemical medium corrosion resistance. Therefore, the following points should be noted when spraying or painting the gel coat layer:
1. When configuring gel coat resin, it must be fully mixed. When the pigment paste is used in particular, if the mixing is uneven, spots and streaks will appear on the surface of the product, which not only affects the appearance, but also reduces its physical properties. For this reason, mechanical stirring should be used for mixing as much as possible, and it is best to use a mixer that does not generate vortex to avoid mixing with air.
2. Gel coat can be sprayed with a brush or a special spray gun. During spraying, 5-7% styrene should be added to adjust the viscosity of the resin and styrene lost during spraying.
3. The thickness of the gel coat layer should be accurately controlled between 0.3-0.5mm, usually controlled by the quality of the gel coat used per unit area, that is, the amount of gel coat is 350-550g/m2, so that the above-mentioned required thickness can be achieved .
4. The thickness of the gel coat layer should be suitable, not too thin, but also not too thick. If the gel coat is too thin, it may not be cured completely, and the glass fibers on the back of the gel coat are easily exposed, affecting the appearance quality. The function of beautifying and protecting FRP products; if the gel coat is passed, it is easy to produce cracks and is not resistant to impact, especially the impact from the reverse direction of the product. The gel coat is unevenly applied, and it is also easy to cause cracks during the demoulding process. This is because the surface curing speed is different, which causes stress within the resin.
5. The gel coat should be applied evenly to avoid local accumulation of the gel coat.
6. The degree of curing of the gel coat layer must be mastered.
The best way to check whether the gel coat layer is properly cured is to use the touch method to touch the surface of the gel coat layer with clean fingers. If you feel a little sticky but not sticky, it means that the gel coat layer has basically cured. Perform the next paste operation to ensure the integrity of the gel coat layer and the backing layer.