Salt Spray Test on Clear Chem Film

A. I have ran a plating facility for the last 6 years and have found a number of problems that would contribute to a salt spray failure. First have you looked into the contaminate contents in your cleaning process, for example copper and chloride content in the deoxidizer. Another thing to look at is the chloride and sulphate content in the Alodine bath, they should not exceed 100 mg/l combined. Last but not least, are you monitoring the cleanliness of the rinse water? It is very important to monitor the TDS and meet the spec requirements. I run all my processes at the nominal times, temperatures, and concentrations to assure success.

Material could have an effect on the failure of panels, look to see if it was the same lot of material. We have also experienced the occasional lab problems and had no control to fix their process. Thanks and good luck

A. I would blame the quality of the panels that you used the second time, assuming that your process line is completely in specification. Old panels, made from aluminum sheet that has been around for a year or so is virtually guaranteed of failure. If it was sheared without flawlessly cleaning the shear bed, you can easily fail for red rust which you should never have on aluminum. Look at the panels very carefully before processing. I could point out areas that very nearly always pitted after the process and salt spray. Missed about half of the areas that did pit.

I have some doubts about several things. How many days or weeks later did you run the second set? How long has the line been in operation. What is the quality of the lab that did the salt spray. Did they do all of the checks or did they "pony" some of the daily data. While salt spray is a rather useless test, it is easy to operate the cabinet out of spec and have a high rate of failure.