Sending out compleated 80% AR Lower to be Anodized

[Gunsnwater]

I am no expert as is well known, but this is what was explained to me.
Once you complete the receiver all FFL rules apply (unless you butcher it and end up with a useless hunk of metal like I did).
If the outside surface is already hardened, the interior cavity will still be raw exposed aluminum that is soft.
People send their builds out to be hardened, but the cost of anodizing the exposed interior cavity is expensive when compared to a budget build.
You don't need to harden the interior, but the receiver will not be as durable and will eventually fail at the stress points below the pin.

I believe from the first cut it is nolonger an 80 and is considered a lower and that is regardless of it working or not.

Anodizing is not hard. Battery acid and a power supply. Dye is optional. Boiling water bath or steaming to close pours finishes it. Google it.

[Gunsnwater]

I dont think you can hard coat anodize at home though.

Yes you can. Hard coat is just a guage of thickness. Anodizing is self limiting because it doesnt conduct. Just let it in longer.

[Walleye Hunter]

When we were kids my sister and I copper coated a nickel using a penny as the donor for the metal. We were less than 10 years old and I don't remember anything about the process but we did it with stuff we found around the house and garage.

[markshere2]

As long as it's an 80% lower, which is not a firearm, then they do not to be an FFL to work on it. It's just another piece of metal in the eyes of the ATF.

Correct..

UNTIL

somebody finishes the last 20%.

Then, what is it?

[alpacaheat]

Correct..

UNTIL

somebody finishes the last 20%.

Then, what is it?

Not an 80% anymore.

I'm contemplating Duracoating my finished 80% (now a 100% technically) once it's finished, but I am probably going to spray myself, or get a PAFOA member that offers those services I can trust to do it. I don't want to run into any problems.

[QuackXP]

Not an 80% anymore.

I'm contemplating Duracoating my finished 80% (now a 100% technically) once it's finished, but I am probably going to spray myself, or get a PAFOA member that offers those services I can trust to do it. I don't want to run into any problems.

I'm still contemplating as well if I want to get an Anodized lower and just repair where I drill/milled to bare metal. Or get one unfinished and do some kind of DIY finish.

[abner13]

All anodizing is not equal. Mil-Spec 'hardcoat' anodizing is what ya want.

http://www.hillockanodizing.com/3.html#

[JustinR]

Side note, I do not believe anodizing strengthens aluminum, it actually will lesson the fatigue strength a tad.

It doesn't strengthen, it hardens and separates.

Aluminum has a coefficient of friction greater than 1; it sticks to itself like nothing else.

Anodizing creates a separation layer to eliminate the friction/galling, and creates a wear surface harder than raw aluminum.

Look up how to inspect a Sig Sauer aluminum frame, you'll learn all about it.

[USMC3531]

Correct..

UNTIL

somebody finishes the last 20%.

Then, what is it?

In the atf eyes it's either a receiver or not. "80%" has the maximum amount of work done without being a receiver. So if you do any work to it it's now a receiver.

[Gunsnwater]

I am no expert as is well known, but this is what was explained to me.
Once you complete the receiver all FFL rules apply (unless you butcher it and end up with a useless hunk of metal like I did).
If the outside surface is already hardened, the interior cavity will still be raw exposed aluminum that is soft.
People send their builds out to be hardened, but the cost of anodizing the exposed interior cavity is expensive when compared to a budget build.
You don't need to harden the interior, but the receiver will not be as durable and will eventually fail at the stress points below the pin.

Any work done on an 80 makes it not an 80. From the first home cut it is now under ffl rules. Ianal. This is what has been explained to me by lawyers in law classes, subject to my lay understanding.

Lots of YouTube videos on anodizing. Not hard compared to turning an 80 into a built lower. Just all sciencey and unknown like building an upper until you do it.

Hard anodizing is just a thicker layer. Anodizing is self limiting as it doesn't conduct.