Runs

Description of problem: 15-_runs.jpg
    Excess paint applied on a vertical or inclined surface doesn’t
    hold and runs along side the panel.

 

Causes:         
    – Spray gun too close to panel.
    – Spray pass is too slow.
    – Wrong spray gun setup (nozzle too wide or air cup too small).
    – Low air pressure.
    – Incorrect viscosity.
    – Bad application conditions (it is too cold or air circulation is lacking).
    – Not enough flash off times between coats.
    – Thinner too slow or too much retarder is used.
    – Hardener is too slow.
    – Paint is sprayed over dirty or oily surface.
    – Temperature of paint is too low.

 

Preventive measures:
    – Use correct hardener and thinner.
    – Ensure that spray gun is in good working order.
    – Warm object and material up to room temperature.
    – Use correct air pressure.
    – Avoid thick coats and observe flash off times.
    – Allow some time before turning up the temperature in the spraybooth.

 

Remedy:
    – Sand and polish.
    – Sand and repaint.