Troubleshooting
Chromate Process

List of common coating defects and remedies

Bath pickles, metal and creates dusty coating

CAUSE
SOLUTION

Accelerator level too high

Reduce accelerator level by processing the aluminium or auto draining and adjusting the bath

Low coating weight

CAUSE
SOLUTION

Aluminium concentration too high in the bath

Auto drain and adjust

Accelerator too low

Add accelerator

Concentration too low

Add make-up chemical

Total acid too high in relation to chronium concentration

Auto drain bath and adjust

No coating

CAUSE
SOLUTION

Total absence of accelerator in the bath

Add accelerator

Sludge plugging in nozzles

CAUSE
SOLUTION

Aluminium concentration in bath too high

Auto drain bath and adjust

Alkaline salts dragged into bath

Increase overflow rate of rinse following cleaner