View Full Version : How do I fix the Black Finish?
While installing my first LPK, I used steel punches and removed the finish from a couple areas. What's the best thing to fix these up with? I'm sure the cheapest solution would be black nail polish, but I'm not sure how well it will stay on. What are my other options? Something more professional would be great, but I don't know where to begin.
I nicked the rear bump at the bolt catch lever, which now shows the aluminum of the lower. The roll pins show silver from where I hammered them in place. My punch slid a little on the magazine catch button, which removed a slight amount of paint on the button.
I've heard that brass punches are softer; but would they still scrape the finish? Most of the finish came off due to the hammer usage with the punch. Would a hammer + brass cause the finish to rub off?
Robb Jensen
04-14-10, 07:25
Birchwood Casey aluminum black will cover nicks in most lowers it does well on steel too but be sure to put oil on it afterwards.
Brass punches will remove finish, too. When I mar roll pins I touch them up with cold blue.
I'm glad to hear that brass isn't much better, since I COULD have bought some... but I chose not to because I already opened my steel ones. :)
Which lower receiver parts are aluminum and which are steel? Some of them I can tell by weight, but some are smaller and it is difficult to tell. The only way I can really tell is by whether they are parkerized or painted. Is there any other way to tell?
It appears that AR-15 steel is parkerized. Is this the best method for steel repair? I think the only parts I damaged were aluminum; but my shotgun barrel has some scratches.
lethal dose
04-14-10, 08:24
Just a thought for future builds taught to me by my local pro... anywhere you plan on driving roll pins with a punch, place electrical tape on your lower reciever so you don't mar your finish. :)
Good advice from LD - when I do a bolt catch roll pin, I swaddle the hell out of the lower with layers of electrical tape!
I am going to pick up some Birchwood Casey today; but I don't know whether to get the paint-on Aluminum Black or the Touch-Up Pen. The pen is supposed to be glossy, but the paint says nothing about being glossy (also mentions being "dark grey"). The parts I damaged were glossy black; can anyone testify for either of these products?
spamsammich
04-14-10, 11:34
I've only used the paint on and it works fine with bare aluminum and I even use it to touch up staked steel or bare metal under the FSB. Make sure to give the parts a good coat of oil after 24 hours and the colors should match up pretty well. Don't get too wrapped around the axle about small patches of bare metal because if you actually use your gun, you'll create more and more eventually. give the exterior a light coat of oil periodically and shoot the shit out of it.
Just a few things. Generally it is helpful when you install the LPK in a particular order. May I ask in what order you installed everything?
I have found that when done properly you shouldn't have any issues. I also use brass punches and find them far friendlier to the weapon than steel punches.
spamsammich
04-14-10, 11:52
Oh yeah, prep is everything when using that Aluminum Black. I have used acetone and non-chlorinated brake cleaner to remove surface oils and dirt. I prefer the brake cleaner. It will strip your receiver of oil so don't be surprised if the anodizing looks weird with no oil, when you hit it with CLP or LP again, the color becomes more uniform.
Be very liberal with the tape if you dont want nicks. I had electrical tape and a brand new brass punch cut into the tape and nicked the lower.
******Hi-jack warning*******
Sorry guys but dont want to start a whole new thread on a similar subject. I just finished cutting off the delta ring on my 6920 to make room for an arms #50m-cv rail system. In the process of removing the snap ring and springs I put some scratches on the barrel nut and barrel nut teeth. Do I need to even worry about this? I know it will be covered, but will it be a breeding ground for rust if I leave the metal exposed?
Robb Jensen
04-14-10, 13:34
******Hi-jack warning*******
Sorry guys but dont want to start a whole new thread on a similar subject. I just finished cutting off the delta ring on my 6920 to make room for an arms #50m-cv rail system. In the process of removing the snap ring and springs I put some scratches on the barrel nut and barrel nut teeth. Do I need to even worry about this? I know it will be covered, but will it be a breeding ground for rust if I leave the metal exposed?
No worries, just throw some oil on it.
******Hi-jack warning*******
Sorry guys but dont want to start a whole new thread on a similar subject. I just finished cutting off the delta ring on my 6920 to make room for an arms #50m-cv rail system. In the process of removing the snap ring and springs I put some scratches on the barrel nut and barrel nut teeth. Do I need to even worry about this? I know it will be covered, but will it be a breeding ground for rust if I leave the metal exposed?
I would coat it. Heat cycles on bare metal and moisture can corrode easily. As far as a product, I wouldnt know off hand, but I assume a B-C product of some sort will work.
I installed the parts in the order specified in the AR-15 Lower Assy guide on ar-15.com. I used 3 layers of packaging tape, and it was not good enough for DIRECT impact. It worked well for indirect movement though. I would definitely use several layers of electrical tape nexttime. None of my installed parts got in the way of installing the parts. My problems arose from not being as steady enough with the punches - slid off to the side & scraped it.
I will get this BC stuff today and do everything as you guys have. Thank you for all the help!
As for the hi-jackers post, I know BC makes Perma-Blue and Super-Blue, which are both paint-on for use on steel. Granted parkerizing is a better finish (and much more elaborate than painting), the BC stuff is reported to work good for small nicks and dings. Reportedly seems to discolor in blotches on larger areas.
I had a lower that had a nasty spot on it that I ended up filing down. I also wanted this particular rifle to be pretty like a princess. Unfortunately Aluminum Black did not match the color very well. Everything else I put on the bare spot, including the touch up pen, seemed to rub right off with mild handling. The winning combination ended up being Aluminum Black covered up with a touch up pen. Now you can't even tell I went to town on it with a file. I still haven't really beat up on this lower, but so far so good. I've also heard really good stuff about Gunkote.
The touch up pen is glossy black when dry, and (IMO) works better on steel than aluminum. And brake cleaner and other degreasers will remove that touch up (pen) paint. I havent used anything else though to cover up scratches. Its also a good idea to use masking tape/painters tape or duct tape to save your lower from damage while working on it. I learned after scratching my first one.
I was very close to buying the touch up pens while at the store yesterday; I'm glad I didn't now! Thank you for your posts!
ForTehNguyen
04-15-10, 07:54
its easier to use needlenose pliers and squeeze the pins in, I've done that for the past 3 lowers. Heck of a lot easier and safer IMO
+ 1 for pressing pins in.
Nothing there should need a hammer and punch.
Of course, you could paint your carbine and just not care about dings and scratches
I sometimes use a black sharpie belive it or not. It works good on small nicks. Regular old flat black spray paint works good to on small nicks. I apply it with a q-tip. Only problem with those 2 is solvents will remove them on contact. I use a blueing pen on nicks on metal parts. Just make sure to oil it good afterwards.
Heavy Metal
04-15-10, 20:15
Good advice from LD - when I do a bolt catch roll pin, I swaddle the hell out of the lower with layers of electrical tape!
Use glass fibre tape for that one. That is my secret. That and a special punch I ground one side off the handle.
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