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Paint Drying Problems

July 9, 2013

Painting is usually at the end of the manufacturing process. Paint drying can be the reason that delivery schedules are met and paint drying problems the reason they are missed. Sometimes, after months of everything running smoothly, panic takes over because the paint isn’t dry and a shipping date is not met.

Eventually, it’s important to know what happened in order to prevent future problems. However, the first priority is to get the product out the door. If you have encountered paint drying problems, here are some basic recommendations:

Paint drying problems can be reduced by:

  • increasing air movement
  • increasing the temperature
  • using package materials
  • reducing application rate

1) Increasing air movement – All paints dry primarily by evaporation of their solvent, whether it’s water, xylol or something else. Increasing the air movement around the painted part will help it dry faster. This is particularly important with water-base paints during periods of high relative humidity.

2) Increasing part temperature – Higher temperatures will accelerate the evaporation of solvents AND cure rate of the coating. Drying and curing are not the same. A coating may be dry to touch but still be soft (uncured). This means it can be subject to damage during handling, packaging or shipping. Raising the temperature of the painted part will speed the curing (hardening) of most coatings.


Drytime tester

3) Using packaging materials – Use waxed paper, shims, desiccants, etc. to ship under-cured coatings as a stopgap measure. Avoid wrapping parts in plastic when possible and never apply plastic wrap directly to under-cured paint to avoid damaging the finish.

4) Reducing application rate – Measure how much paint is being applied. Thicker paint films take longer to dry. Subtle changes in painting practices can result in more paint being applied. If you discover more paint than usual is being applied, check the following:

A) Spray equipment – Worn spray tips apply more paint.
B) Painting techniques – A new painter may be moving slower and applying more paint.

Shipping schedules are sometimes missed because of paint drying problems. Applying these techniques may help get you through the bumps caused by seasonal variations and slight changes in the process.