Causes:          
    – Thickness is too high which leads to an external drying while the solvents
       are trapped in the paint film.
    – Paint is sprayed over wax, oil, and grease.
    – Drying in bad conditions:  Workshop is too cold, humid and non-ventilated.
    – Bad application conditions:  Not enough air circulation and/or heat.
    – Not enough flash off time.
    – Too much retarder used.
    – Incorrect hardener or mixing ratios.

Preventive measures:
    – Clean surface thoroughly before painting.
    – Avoid thick layers.
    – Improve spraying and drying conditions (heat, air circulation, etc.).
    – Allow enough flash off times.
    – Use recommended hardener and thinner and observe mixing ratios.

Remedy:
    In general, it is possible to remedy a slow drying problem by moving the vehicle to a place where the ventilation and the temperature are more appropriate or by heating at a moderate temperature (unless the problem is due to the use of a wrong hardener or wrong mixing ratio of hardener – non stoichiometric ratio).  If the problem is due to very thick layers, “des rides” may show, except if special care is taken during the heating phase.