Protecting engraved aluminum

Well I will start here and if there is a better place to post this, I will soon find out... I am new to CO AR-15 Shooters.

I have a new SBRed AR-15 lower. That is, it is now legally registered to be mated with a 9mm short barreled AR-15 upper.

As some of you may know, the NFA branch of the BATFE requires that this thing be engraved with my name. On my application, I told them I would engrave my first two initials followed by my last name, spelled out - like everyone else does, and OF COURSE they came back and told me I had to have my full name on it. You also have to have your City, State, and caliber engraved on it too.

Any woo, I now have an aluminum lower receiver with alpha-numeric carvings, at least 0.003", no smaller than 1/16" in it, and need a way to protect the bare metal that was previously nicely anodized. I have tried Birchwood Casey Super Black (looks pretty crappy), Lacquer Stik (http://www.markal.com/productDetail82.aspx) but it easily wipes right out of the low spots, and Birchwood Casey Aluma Black (I just don't like DIY cold metal finishes). Fortunately acetone takes off the experiments (except for the Aluma Black that didn't really do anything, anyway)

I have considered the following:
1. Testors model paint carefully applied with a small brush, toothpick, or matchstick.
2. Taking it all apart and sending to an anodizing shop.
3. Plan F - asking you fine people.

Any ideas?

[UZI]

unless you are concerned about the bare metal getting dirty, or wanting to do it in a color other then black, why worry. it's Al it will never rust.

oh yeah, velkomme

Well, to be strictly accurate, it will very quickly "rust" with a coating of Aluminum Oxide. The anodizing process just applies a more uniform/thicker/dyed aluminum oxide layer, but the natural formation will prevent corrosion.

Cerakote it black, if you've got even a cheap airbrush or pick one up you can order it from Brownells. Its pretty easy to apply and bake in the oven, just keep your coat even and thin. Its an option.

paint it red like spikes tactical does their spiders and bullet markings on their lower receivers. might be cool! just use red paint (or whatever color you want) and a toothpick to apply it. might turn out cool!

I was wondering if the initial coat of oxidation would be protective. That's good to know. I should hae figured that one out, but I kept hearing how important it was to protect the metal. I have used Cerama Coat - the bake on paint (on a Makarov pistol and really liked how it came out) - tough stuff. If I don't have to take the innards out I would be a lot happier though. I wonder if I could just mask the bits off that I don't want painted... Paint is definitely looking good as an option. I tried yellow, black, and gray Lacquer Stik. They were all a slight improvement over bare aluminum (just would not stay on). I may just go with the toothpick applicator after all. I'll get a picture posted if I can. Thank you much!
[Beer]