A quick note on Alodine: Not worth the safety and material disposal hazards. Remember the movie
Erin Brockovich? That's the same cancer this stuff can cause with improper exposure and handling. Given how this stuff has to be disposed of, stored, and handled, compared to the results it produced, I don't think the juice is worth the squeeze. To be fair, I only tried it once and I could have improperly applied it, or achieved better results with a different process or more practice. Your results may vary.
Here's the images I found of what it produces (great, right?):
Attached File Attached FileHere's the results I achieved with media blasted parts: One 7075 upper, and a piece of a 6061 DD RIS II rail (partially blasted to see how it affects factory anodizing). Both parts were media blasted and sterilized in acetone prior to the alodine bath.
Attached File Attached File(Shown "wet")
Attached FileShown next to known colors.
After rinsed and dried, I noticed there was a powdery substance on top of the parts that would wear away easily with handling. Unfortunately, that powder was indeed the color, as well. So as you handled it, the color of the part would fade and look thin. The blotchiness of the color doesn't bother me. I didn't like the orange tone it produced. And my only thought to preserve the color before it rubbed off with handling was to immediately Cerakote it in a matte clear.
All in all, the results didn't warrant further review for me. If time wasn't a factor, I might try again and refine the process (I have a whole gallon of the stuff sitting here), but overall it was more work than I could justify for the results achieved.