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Old December 20, 2020, 05:56 PM   #1
Hdonly
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Birchwood Casey Aluminum Black

I did a couple of AR-15 80% lowers in the raw recently. Followed the directions by scrubbing with a sotchbrite and detergent. Followed with a good rinse, then a good wash with 91% isopropyl alcohol. Let dry and applied the blackening with a foam brush. I am not very pleased with the final product. Anyone have any hints as to flaws in my procedure? Thinking maybe acetone or mek degreaser? Or maybe sandblasting is needed first?
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Old December 20, 2020, 06:23 PM   #2
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Aluminum black is for touch-ups on worn anodized aluminum frames.
You need to have your frame anodized or paint it.
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Old December 20, 2020, 09:50 PM   #3
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I had similar results with a pistol frame. Cerakote is probably a better option.
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Old December 20, 2020, 11:56 PM   #4
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Lesson learned. I was thinking "It's a chemical reaction, it should color the metal evenly". Guess that's why I'm not a chemist- haha
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Old December 21, 2020, 03:07 AM   #5
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Now I got to get this stuff off. I used a scotch-brite pad on the easy to get places. I think I will try blasting with walnut shell so I get the hard to reach places. Will see how that works. What a mess.
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Old December 21, 2020, 02:33 PM   #6
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yeah, as stated that is meant for touch up. Never used cerakote myself. Did use the Brownells Gun-Kote, which is similar to cerekote, just in a rattle can. worked reasonably well, just follow the directions.
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Old December 22, 2020, 02:46 PM   #7
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I guess everybody is going to 'splain to me that BC Aluminum Black is only for touch up. Guess you guys never heard of "Well, you never know till you try". haha
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Old December 22, 2020, 04:49 PM   #8
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Hdonly,

I reduced your image to fit on the average screen. Please try to avoid more than about 1024 wide, as it makes people use the horizontal scrolling feature to see everything.

I've actually used that kind of chemical to produce a flat black finish on some aluminum channel stock that I was using as electronics heat sinks. It took me a while to figure out how to get it even. Still, I found that by applying it with a discarded toothbrush and constantly scrubbing to get the loose spots off and replaced with fresh black, I could eliminate the uneven bare spots and pinholes and wind up with coloring that didn't rub off easily. This is going back 20 years, but I also seem to recall I diluted the chemical with three parts distilled water by volume to get time to scrub adequately, but I may be remembering that incorrectly. I do that with a steel blackening product, and I could be misrecalling that I did it with both.

I like the very flat black that results. It is functionally desirable for heat sinks (good IR emissivity), and I use similar chemical blackening on iron sights that I have first abrasive blasted with 400 grit aluminum oxide to give them a good, smooth dark matte surface to react with the chemical. It hangs onto that blasted surface pretty nicely, but it is not as rugged as a Cerakote finish applied to the same sort of surface. You could apply a protective clear coat to it, but then you will lose the flat aspect of it and will be better off just going straight to Cerakote or Aluma-hyde.
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Old December 23, 2020, 12:07 AM   #9
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Trying a resize image. Got most of the Aluminum Black off, but the metal is discolored. Going to walnut blast them and do some polishing next.

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Old December 23, 2020, 10:33 PM   #10
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Quote:
Originally Posted by Hdonly View Post
I guess everybody is going to 'splain to me that BC Aluminum Black is only for touch up. Guess you guys never heard of "Well, you never know till you try". haha
yeah, but generally when trying something new you want to go slow. perhaps a test inside the mag well, then 1 full receiver, rather than going for broke on both? something similar to the old measure twice cut once adage.

If you going to coat or paint it, all I would think you need to do now is lightly scuff and apply...
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Old January 2, 2021, 05:52 PM   #11
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Well, got one cleaned up. Not a mirror chrome polish, but it sure looks better than it did!



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Old January 2, 2021, 06:54 PM   #12
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Just leave it like that.
If you paint it, it will need to be blasted first, and you will have wasted all the effort.
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Old January 2, 2021, 08:33 PM   #13
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If it is going to be Cerakoted or Gunkoted it will get abrasive blasted first.
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Old January 3, 2021, 04:12 PM   #14
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Do you drink the beer before or after completing the work?
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Old January 3, 2021, 07:16 PM   #15
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Quote:
Originally Posted by Unclenick View Post
Do you drink the beer before or after completing the work?
In my case the answer is 'Yes'.

I've used Birchwood Casey Aluminum Black for years. I have found it to work better on some alloys than others. It has worked particularly well for me on aluminum scope bases. I recently used it to blacken a Weaver mount I hogged out as a 'easy load' mod for low rings my old 721 Remington. The coloring was a perfect match to the OEM color and has held up well.

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Old January 4, 2021, 10:52 AM   #16
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On the beer question, I must agree to the answer "Yes". But I only drink beer when I am alone or with somebody.
I'm sure the alloy has much to do with how well the blackening works. I like the polished look so I think I will polish the other one out. It takes about four beers to polish to this level.
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Old January 4, 2021, 11:53 AM   #17
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I'll use it on aluminium, but for an AR lower, I'd rather bead blast and paint.
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Old January 5, 2021, 06:28 PM   #18
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I just scrubbed and degreased the last lower down. Tried something different that I read about. CRC dry film lubricant. Looks pretty good. I rubbed hard on it after it cured with a fresh white cloth. I couldn't rub anything off. I'll see if it holds up.



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Old January 6, 2021, 10:08 AM   #19
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Not quite a match, but still looks good.

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Old January 6, 2021, 11:02 AM   #20
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I used the Birchwood Casey Aluminum Black on a few of my raw AR lowers. I lightly sand blasted them first to rough up the finish, then I heated the lower until it was hot to the touch, put it in a gallon Ziploc bag & dumped a whole bottle of the Birchwood Casey Aluminum Black in on top of the lower ziped it closed & shook it to cover the entire lower fast. It got real hot from the chemical reaction but after I washed the bluing off & soaked it in gun oil & let it cool down it had a black scale covering it. I used a plastic spoon to remove the scale & it was good & black under the scale.
It was a little too much work so now I just use a black spray paint called VHT engine enamel. I just spray it on let it dry for 24 hrs the cure it by putting it in a 200° oven for 30 min. It is a tough chemical resistant finish that all the gun cleaners in the world won't take off.
https://www.vhtpaint.com/high-heat/vht-engine-enamel
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Old January 21, 2021, 11:35 PM   #21
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I believe that Cerakote or Duracoat would offer a superior finish to the blackening agent used.
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Old January 22, 2021, 11:20 AM   #22
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Uhh, do not leave it like that, yes it is polished, it is still raw Aluminum. Have it anodized or paint it, raw Aluminum requires a finish.
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Old January 22, 2021, 03:15 PM   #23
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Aluminum doesn't "require" a finish.

Aluminum produces it's own layer of aluminum oxide when exposed to air. This prevents it corroding or discoloring.
I have pistols with raw aluminum frames that I have owned for decades and they still look like new.
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Old January 24, 2021, 06:20 PM   #24
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I've seen aluminum bloom white oxide clumps, so I'm not convinced that the fast-forming surface oxide layer is always adequate under all conditions. But raw aluminum that gets rubbed with a silicone rag or gun oil or such will probably do fine.
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Old January 26, 2021, 07:37 PM   #25
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It will really depend on the environment. One of my homes is close to the ocean. Salt air and raw aluminum, no thanks. In my world Aluminum must have a finish.
YEMV Your environment may vary.
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