Next, the parts were stripped, de-smut'd, and run at the same CD all together in a mixed batch. Here is the really interesting part... This entire effort began with the goal being a scientific approach to CV anodizing. All the while in the back of my mind I'm thinking that I really want to get away from having to calculate the surface areas of irregular parts, but knowing full well the consistency of the CC LCD method will yield the best results. Well, after studying the volts curves, and trying to come up with the best of two worlds, here is what I did:
I picked a number... 15 volts.
I racked the freshly cleaned parts, checked the temperature, turned on the air agitation, turned the amps all the way up, started with the volts all the way down, and turned on the power supply.
Now, I slowly ramped up the volts (really slowly) to 15 volts. After 5 minutes of the start, I noted the amps (they were steady now), and slowly turned down the amps until they just began to drop, then bumped them back to the steady number. Now I turn the volts all the way up. This move produced a seamless transition from CV to CC. Now I ran the rest of the duration at this setting for two hours. At the end of the process the parts were dyed black with outstanding (normal) results. BTW, at the arrived amps, I reverse calculated the current and known SA, and guess what? The CD was just a tad over my target of 6A CD. YAY! Here is a pic of the finished mixed batch. The 2024, and 7075 came out ever so slightly darker, but that is somewhat normal. I often have to adjust dye times of mixed batches so that all the parts come out the same... hopefully with the smut info, I'll be able to predict (and you, now) which parts will give me dye problems.
Any comments/feedback is greatly appreciated. Did I leave anything out? Did I make any mistakes?
Hopefully somebody out there can use some of this info. I know I'm pretty excited to try the same method with other colors. I hope to have some real thickness measurement to go with these results soon as well.
Enjoy! -Acid