Birchwood Technologies Presto Black STEEL PC9 - versatile blackening solution for iron and steel alloys traditional patina blue and black oxide touch-up (8 oz)

This worked very well for my tools. It contains Selinium, so please dispose of it properly. I've collected my wastewater for the next hazmat drop off. There's more involved than I can fit into a review, so I'll include a photo. It only works on steel (I knew that), so you can see/expect things like the stainless bolts stay shiny. I didn't even try the aluminum handles; I dismantled most of these and cleaned and treated them individually using a 1:9 distilled water solution in an ultrasonic tank (using an isolation jar for the solution). The only refinement post-oil (camelia in my case) will be a topical microcrystalline wax, but this is already a 'standard' coat and much better than what I started with. If you're doing a more direct brush-on application, then my experience may not apply to you.

Dang, this stuff works so fast you better not blink!! The beauty ring bolts in my bronco were kind of messed up from removing a couple times so bare metal was showing through the black. I poured some of this stuff on a bowl, dropped the button head torx bolts in and Shazam! No more silver was showing. Incredible. They look fantastic. One difference from the stock bolts is these come out with a matte black finish while the OEM Ford bolts have a shine on the black. I waxed these baby’s up and they look very, very close to the stock ones. Nobody would ever know. I got so punch happy I took my eyeglasses apart and threw the frames in but no go, this stuff only works in steel not aluminum. Oh well, can’t win ‘em all. This stuff works really well, if you need to blacken some steel hardware…get you some!

Works fantastically. Produces a much darker black than other bluing agents and works on alloys that others don't color well.

Not bad for touchups, but for larger pieces, there are better products. Overall, easy to use and economical.

I recently had some bolts on my gun get discolored after stripping the phosphate coating off when removing a paintjob. These refreshed them to a nice dark black in just a few minutes. Very simple to use: just get a little stainless bowl and soak your parts for ~15 minutes. Clean with water and rubbing alcohol afterwards. Make sure to re-oil the parts. Will be using again for sure.