Rust Bluing an AR Lower

[Rekrab]

Is this an advisable method to use on an unfinished AR lower? I was wondering due to the threading and small holes in the lower. Would a rust blue still work or would it possibly damage the finer points of the lower?

[247Nino]

not sure if aluminum rusts

[echoarms]

Will not work on aluminum.

[Rekrab]

/facepalm

Right, never mind.

[tlillard23]

Is this an advisable method to use on an unfinished AR lower? I was wondering due to the threading and small holes in the lower. Would a rust blue still work or would it possibly damage the finer points of the lower?

don't listen to the other guys, they are being word freaks... The aluminum will "rust" (word reserved for iron)

Cover the lower in a natual grease, like bacon fat. let the lower sit out for 24 hours. Apply second coating of grease, elevate to 100 degrees F. Continue untill the wife asks for pancakes...

[247Nino]

I think Aluminum only oxidizes, white, hmm not rust. Well I guess you should try it on a soda can? I've never seen a rusty soda can.

http://lmgtfy.com/?q=rust+aluminum

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=rust+aluminum

you must blacken! http://www.birchwoodcasey.com/metal/aluminum.html

[psssniper]

Rust Never Sleeps

[Rekrab]

See, this is why I was an English major.

Maybe I could get some scrap aluminum and test it out just to see what kind of changes, if any, occur.

[nicoroshi]

Aluminum will oxidize like all metals but it oxidizes white not a redish color like iron will.
Copper= patina (greenish color)
Stainless Steel= Clear (Yes even stainless does oxidize).

I do not know if the oxidation of Aluminum will turn black if boiled (never tried it personally) so really not sure if a 'rust blue' would work or not.
You could give it a try though on some scrap aluminum.
Please post your results for us as being a metal worker by trade I am interested in your findings on this.

[Rekrab]

I think I'll do that, if nothing else it will be a fun experiment and I can always recycle the chemicals for an AK build.

[rjf]

I've never seen a rusty soda can.

I must be getting old

There was a time long ago when drink cans were steel. Had to open them by punching a hole with a can opener.

[E-120]

It corrodes. Either surface corrosion or inter granular

[tlillard23]

mmmmm, bacon!

[mzimmers]

Strictly speaking, aluminum does oxidize, but it won't produce a hard, durable finish like steel bluing. Is there a reason you don't want to just anodize it? That's really the way to go IMO.

[scribe]

Concur. Get it anodized. If you don't want that, there are spray on finishes that you bake. Brownell's sells them.