Bleeding: A change in color of the paint that results from the pigment, or other colored material in the surface beneath the coating, moving upward into the applied film and becoming visible.
Cause:
1. Contamination, in the form of soluble dyes or pigments (especially red), on the older finish before it was repainted.
2. Wrong thinner or reducer - too slow.
Prevention:
1. Thoroughly clean the areas to be painted before and after sanding, especially when applying lighter colors over darker colors. Avoid using lighter colors over older shades of red without applying a sealer first.
2. Select the thinner or reducer most suitable for existing shop conditions.
Remedy:
Apply a sealer before reapplying the color coat.
To be continued…
Sent in by Richard Soroketa-Chukwuemeka Nwokocha, BSc. Industrial Chemistry, QC Inspector in Coating and Insulation.
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