Q. We have a square transfer system with 36 tubular stainless steel anodes. At the present time we do not rotate the anodes. Is rotation in the electrocoat tank recommended? If so, at what frequency? J.R.
A. Yes. By rotating the tubular anodes in your electrocoat system you can improve coating quality and, more importantly, increase the service life of the anodes. Rotation enables the anodes to expose different surface area to the workpieces to be coated, minimizing pitting, balancing the consumption and wear of the stainless steel anodes, and increasing their useful life.
Typically it is recommended to rotate the anodes every three months for high process loads or every six months for normal processing loads. Some electrocoat systems rotate the anodes 45 degrees per rotation and others 90 degrees, depending on the diameter of the anode. Anode manufacturers recommend that the current density per anode does not exceed 5 amps/sq ft of work coated. Higher current densities greatly contribute to the dissolution and short life of the stainless steel anodes.
Your specific system configuration, the rate of coating, the geometry of the parts in your tank, and experience will define the proper frequency and angle rotation.