Anodizing with a rectifier

[sgunn911 New User Find all posts View Profile Close sgunn911]

In my experience with using a CC rectifier, I found that sometimes the "90 minute rule" doesn't seem to get the anodize to PAR. Can you just watch the voltage and stop anodizing when you see the voltage start to climb to keep the current constant meaning that PAR has been reached?

Also, in a previous topic "finishing techniques" I was confused about finished after anodizing because the anodizing manual says you can polish the piece with a loose cotton wheel and white compound.

[Fibergeek Metal Finishing Guru Find all posts View Profile Close Fibergeek]

I wouldn't call the "90 minute Rule" a rule, and I wrote it, its a guideline.

4.5 A/sq.ft. is the center of the published LCD range; which is 120 min at 3A/sq.ft. on the low end, to 60 minutes at 6A/sq.ft. on the high end. These times are based on the "720 Rule" for anodization time, and are intended to produce a layer 0.5 mils thick. A good general number for Type II intended for dyeing. PAR can be illusive if your operating conditions aren't right, I would suggest that you follow the 720 rule.

Sanding/grinding, or polishing an anodized layer can be hazardous to the layer if the work can flex or oilcan, just like with any other thin ceramic.