Up until now I've been anodizing using constant voltage, and I've had good results, except for recently. So today I decided I would do a run using constant current.
I measured my surface area and found that it was approximately 1.76 square feet. Then, using the 720 rule, I calculated that the parts should run for 180 minutes at 7.04 amps (4asf).
So I put the parts in the tank after degreasing and deoxidizing, and set my power supply for 7 amps. The voltage started at 30 amps, and slowly dropped (when I left the shop about 15 minutes later, it was down to 27.1).
I made it back just in time to shut off the power supply at the 3 hour mark, and the voltage was at 24.3, which seemed absurdly high. I took the parts out and this is what I found:
Any ideas what happened / what went wrong?