In hot spray applications, the coating is heated up to around 40ºC to 65ºC thus decreasing its viscosity. In this way, less thinner is used to reach the application viscosity. Reducing the amount of thinner used minimizes the amount of solvent dispersed into the atmosphere while also obtaining thicker coating films with smaller number of applications. On the other hand, the relatively lower surface temperature compared with that of the coating forces the coating to cool off as it contacts the surface thereby increasing its viscosity along with the risks of sagging that may develop on the surface.
In any case, a heating apparatus is necessary for such an application method. However, the necessity of designing heating so as to prevent risks of flashing and fire limits the use of hot spray applications.