Hello all,
I have been busy with experiments... here's what I've been up to:
I was able to obtain some different alloys... 2024, 5058, 6061, and 7075. First part of the experiments involve observing the smut produced from the etch process. I use 1 can of Red Devil Chrystal drain cleaner per 3 gal. RO water. The parts were allowed to etch for about 3 minutes at 70F, then rinsed in RO water, and arranged for photos... top left-7075, top right-6061, bottom left-5086, and bottom right-2024.
7075- Black, almost sooty smut appears quickly, and is easily wiped with a rag.
6061- No smut to speak of.
5086- Very little smut, slightly yellow smut that can be wiped with medium ease with a rag.
2024- Gray/black smut appears with medium speed. Not easily wiped with a rag.
Next was the individual anodizing of each of the alloys. Anodizing was temperature controlled to 70F as close as possible, and notes were taken at 5min intervals all through the process checking volts and temperature. Surface areas were carefully measure, and amps were controlled with a digital CC/CV power source. Racking was with Ti racks (previously pickled), and agitation was with thorough air bubbling.
Titration of my ano bath shows the acid concentration at ~200g/litre of water, and aluminum content at 1.8g/litre. I'm not sure exactly what this means, but it is a standard 1:3 acid/water mix that I have been using for about a year now with no problems. Here are the graphs:
