Zinc Phosphating

Phosphate or accelerator concentration too low

Increase concentration

Phosphate bath temperature too low

Increase phosphate bath temperature

Process time too slow

Lengthen time phosphating stage

Phosphate or accelerator concentration too high

Decrease concentration

Process time too long

Shorten time

Poor rinses

Keep rinse overflowing

Excessive sludge

De-sludge tank

Accelerator concentration too high

Allow concentration to drop

Higher bath temperature

Lower the temperature of the bath

Poor cleaning

Check cleaning tank

Low concentration of phosphatizer or accelerator

Increase concentration

Poor solution coverage

Check racking and nozzles

Resistant to metal

Add Jernstedt salts to rinse or lean tank

Coating weight too low

See “Coating Weight too Low”

Dry-off between stages

Run at lower temperatures, better placement of nozzles

Final dry-off too slow

Increase temperature in the final rinse using air blow off

Higher free acid pointage in phosphating bath

Reduce the free acid pointage

Poor exposure to cleaner solution

Increase the pressure if necessary

Poor cleaning

Check cleaning stage

Poor rising

Better arrangement of nozzles

Dry-off between stages

Use fog nozzle, run at lower temperatures