A customer needed a scope mount for his Bullseye gun. It’s not a particularly difficult part to make, I’ve done it before many times but I always just spray painted the parts with Cerakote or even a regular Rust-Oleum matte black paint.

This time, however, I decided to go big or go home and instead of paint use proper anodizing. I sanded and cleaned the rail as much as I could (it still has a few deep scratches but they are barely visible). Then sand blasted with 120 grit aluminum oxide and cleaned again.

The anodizing bath is 1:1 ratio of distilled water and battery acid from the O’Reilly auto parts store. I set my power supply to the constant current of 1.5 A and the voltage was between 17 to 17.5 V. I let it anodize for about an hour, then disconnected the power and moved the rail to the dyeing bath for about 30 minutes, then boiled it in distilled water for another 30 minutes and then put a very light coat of oil on it. The result was a pretty smooth black matte finish.