Troubleshooting
Iron Phosphating
Coating defects, de-greasing, rusting, poor adhesion
Poor coating formation in phosphating stage
CAUSE
SOLUTION
pH not in range (see “Poor Cleaning”)
Adjust pH (down with acid, up with Caustic)
Poor cleaning in de-greasing stage
CAUSE
SOLUTION
De-greasing in bath
Increase the bath temperature
Temperature too low
Increase concentration of the bath
De-greasing in bath
Check racking and nozzles
Concentration too low
Check pressure
Poor exposure to cleaner solution
Increase the pressure if necessary
Poor paint adhesion
CAUSE
SOLUTION
Phosphate Coating too heavy
Lower temperature, lower concentration
Contamination
See “Poor Cleaning”, look for source of silicone near washer
Bad steel
Check raw material for excessive oil
Rusting
CAUSE
SOLUTION
Coating weight too low
See “Trouble Coating Weight too Low”
Dry-off too slow
Increase temperature in the final rinse using air blow off
Drying between stages
Run at lower temperatures, better placement of nozzles
Spotty coating / Streaking
CAUSE
SOLUTION
Contamination rinses
Check rinse tanks
Poor cleaning
See “Poor Cleaning”, check racking
Poor exposure
Check nozzles
Solutions foaming in de-greasing
CAUSE
SOLUTION
De-grease bath temperature too low
Increase the bath temperature
Pressure too high
Check for plugged nozzles
Pumps picking up air
Check pump packing, check water level