Hello, I started anodizing aluminium parts I machine. For electrolyte I use a 16% sulfuric acid agitated with aquarium air pump. I degrease parts in a degreaser, rins them in water, and then put them in anodizing tank. I use caswell 720 calculator to calculate a current for anodizing using a 6amp/feet current density. After anodizing I seal a parts in boiling water mixed with caswell anodizing sealant.
The parts are small sheet metal lids, I use a titanium rack and anodize 30 lids at a time
The problem is that I am not getting a stable process and most of the parts has white/slight yellow stains on a surface. I would appreciate some guidance in solving this problem.
Photo with a staining attached. If the part is wet, the staining is not visible, but when dried, it is pretty visible.