What should one do when Hazing or Blooming is observed on the paint?
Hazing – dulling or loss of gloss caused by microscopic surface irregularities
SOLUTION: Surface dried too quickly reduce quantity Cobalt used. Blooming – as with hazing but may be removed with washing.
SOLUTION: Add Zinc or Calcium driers to retard surface dry
• Paint films are Brittle & Chalky.
Reason: Too much primary drier added causes continued oxidization with premature film breakdown
SOLUTION: Reduce levels of Primary drier.
• No Loss of Dry observed on paints.
Reason: Drying time of coating takes longer after aging caused by adsorption of active driers by pigments.
SOLUTION: Add Calcium at the grinding stage and active driers last
Addition of Driers during paint manufacture - important points to remember:
1. Add Ca or Zn octoate while milling for pigments with high surface area : volume ratio or highly absorbent pigments (carbon black, signal red & dark colours)
2. Single component driers – add Ca, Zr, Co in this order & last stage before adjustments
3. Add antiskinning agent last
4. Add mixed driers at end of let down, before antiskin
5. Don’t premix driers & antiskin
6. Don’t use with or near oxidising agents
7. Avoid premixing single component driers