Birchwood Casey Aluminum Black Touch Up - 3 oz

I'd heard this stuff is the way to go for filling in the engraving you must have do when manufacturing an NFA item (like an SBR lower) and I heard right, it gets right into the engraved surfaces and turns them black as Class 3 anodizing! It looks like it left the factory that way! As for touching up scratches it seems to do OK but keep in mind it's just a surface treatment and isn't really penetrating the metal like anodizing does so if you're trying to re-black an area that sees a lot of wear you may not get the results you want, gonna have to re-ano or cerakote.

this is the product that i used to touch up a black anodized lower receiver where i installed the TBB pdq ambi bolt catch. if you have looked into the pdq ambi you know that the lower must be modified slightly to accept the upgrade and the bare metal exposed only need be hit with birchwood black and it will blend perfectly with the original black anodized finish. the end product for me looks & presents factory all the way around thanks to this handy trick. no drips, runs or color contrast. too bad i can’t post pictures like most other websites.
i now also use this to touch up anything anodized or painted black on aluminum uppers, lowers, hand guards, optics, etc. all of my older or 2nd hand parts look new again. great for repairing booboos, oppsies, scratches etc.