Zinc Phosphate Test Panels look bad - Need Help

[timber]

Help we have a 10 stage zinc phos. system with a pickle stage i can not get good looking test panels all mech. issues have been solved ie drydown, porr cleaning etc the tanks are all in chem spec. temps are good all the known aspects are good nut the panels are still bad crs,and hrs look streaking like drydown or prephos. no idea on it i have even recived the msds on lube used on the parts any ideas,

[Wes Bucey]

In Reply to Parent Post by timber

Help we have a 10 stage zinc phos. system with a pickle stage i can not get good looking test panels all mech. issues have been solved ie drydown, porr cleaning etc the tanks are all in chem spec. temps are good all the known aspects are good nut the panels are still bad crs,and hrs look streaking like drydown or prephos. no idea on it i have even recived the msds on lube used on the parts any ideas,

My only suggestion is to call the factory supplying your zinc phosphate chemicals. Supply good quality digital photos of the observed streaking. There is a high probability they have encountered something similar and will have suggestions.

More intensive research can be expensive by involving metallurgists and chemical analysis.

You refer to "test panels" - what is the final product to be coated? Will it be used as is or additionally painted? Is this an appearance item or strictly functional rust preventative on non-cosmetic components?

Is this an in-house process on your own parts or are you a metal finishing vendor providing service to other customers?

[diptankd]

I had a simular problem. My cleaning tank was in spec but there was a build up of oil from the product in the tank causing streaking. I emptyed the tank and recharged it problem went away. You can try an activator in the rinse tank before it goes into the zinc tank that will help also. Good luck.

diptankd