Pinholes or pinholes in the cured paint surface are not only annoying, but can also reduce the protective properties of the coating. The holes can go all the way down to the substrate, opening the way for water and dirt, which causes rust and peeling. Since the problem cannot be corrected afterwards - the pores will only return in a new coat -, it is best to prevent pinholes in the first place. The holes occur when air or gases become trapped in pores in the substrate or as bubbles in the paint. Normally, the air should rise to the surface and evaporate, but if the coat was too thick or the surface cured too quickly, the evaporation process does not have the time it needs. Therefore, it is important not to apply too thick coats at a time and to ensure that the substrate is as pore-free as possible.
The causes of pores can be many:
- Too late evaporation of solvents
- Using incorrect spraying technique (too high pressure)
- Paint is applied with too high a WFT (wet film thickness)
- Application occurs in too strong a wind
- The spray gun/spray is held too far away from the surface.
