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Thread: Ultrasonic Cleaning of AR BCG

  1. #1
    Senior Member jet3534's Avatar

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    Ultrasonic Cleaning of AR BCG

    I want to try cleaning an AR Bolt Carrier Group in an ultrasonic cleaner using a water based solution. Would putting the BCG in an oven (at say around 200 degrees) after cleaning be sufficient to remove all water residue? I see people using an air compressor to blow dry parts after ultrasonic cleaning, but I don't have an air compressor. Also, is it totally inappropriate to use even a very small quality of protective lube such as CLP on a gas key after ultrasonic cleaning? I have really done very little shooting with an AR, so I don't have much of an idea about how resistant they are to corrosion. I have to say that after many years of AK shooting, I now prefer the AR ergonomics. Not sure why. I guess it is sort of like one's taste in music can change.

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    Senior Member NAPOTS's Avatar

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    I really don't think it's necessary. Disassemble, clean firing pin, cam pin, bolt, extractor. Use one of those carbon scrapers for ther inside of the bolt carrier. A few patches and your favorite cleaner. You can get the inside of the bolt with a patch on the end of a screw driver too or a dental pick. I don't think it really needs to be all that clean for it to function well. A few q tips. It doesn't take me that long to get mine clean and after getting a routine down I don't think it's very much trouble. Also don't go crazy with the lube. After you have some rounds through it the wear will tell you where it needs oil. No need to drown it. To much and that shit will burn off and blast your eye pro from around the charging handle
    Last edited by NAPOTS; 10-29-2017 at 06:47 PM.

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    A simpler method is after running the parts in the ultrasonic cleaner, rinse well under running HOT water until the parts are warm.
    Shake well to throw off any excess water, and the heat will usually finish drying it.
    To make sure, don't put it in an oven, that's overkill. Simply use a hair dryer to warm the parts to finish drying.
    NOTE: Hair dryer, NOT a torch or heat gun.

    Another method is to use a carbon tool like the CAT 4 then soak in a carbon remover like Slip 2000 Carbon Killer. Then do the rinse under hot water.

    The USGI manuals show putting a drop or two of CLP in the front of the gas key to lubricate and protect it.
    To lube the rest of the carrier to prevent rust, I put a few drops of CLP on a soft toothbrush and "scrub" all surfaces.
    This will leave a very thin coat of protective CLP on everything.
    You still have to apply lubrication to key areas like the carrier rails and cam surface.
    I use a light coat of grease on the cam key and the cam area, and on the carrier rails.
    Unlike CLP or other liquid lubes the grease stays put and won't run off.

    If you notice, if you lube the AR with a liquid lube then store it muzzle up and leave it a few days, when you open the rifle you'll find a fairly heavy coat of lube on the front of the buffer.
    This is the lube that ran down and off the carrier and bolt.
    Grease will stay where it needs to be.

    Last, ultrasonic cleaning can be very effective and will remove fouling and ALL lubrication from areas no other cleaning method can get to.
    However, it often takes longer to set the cleaner up and fill it then empty and put away after use then is worth the effort.
    Other methods may be actually faster if not quite as effective.
    So, I usually reserve use of the ultrasonics for occasional deep cleaning use, and use the faster methods for normal cleaning.

    How effective ultrasonics are at removing AR carbon fouling depends on the cleaning solution you use. It has to work on carbon fouling, but not harm the finish on the parts.
    Choose carefully.
    Note also that many of the soap based cleaners WILL attack the anodized finish and the aluminum of aluminum parts and do so even faster in an ultrasonic cleaner.
    This can happen fast, and by the time you look the parts are already ruined.

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    Senior Member jet3534's Avatar

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    Thanks guys for the feedback.

    I recently tried some of the SLIP 2000 Carbon Killer on difficult to clean parts and for me the results were mixed. It did take most (but not all) of the Carbon off of the face of a stainless revolver cylinder - i.e., I removed the cylinder and soaked it in the Carbon Killer for several hours. On the other hand it was ineffective in removing Carbon from a Ruger SR556 gas piston and at best marginally effective removing Carbon from a SR556 gas regulator.

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    I had the same mixed results with Slip 2000 Carbon Killer on my AK-74 muzzle brake.

    I would soak it in the jar for an hour then rinse. I didn't soak longer without the rinse for fear of damage to the outer finish.
    It's hard chrome lined.

    After that I tried packing the brake with paper towel and soaking the towel with Hoppe's #9. The towel would come out after a few hours bright blue from the copper plated steel bullets, so I'd repack and soak again.
    I did this for as long as 2 days and the inside was still black.
    I even tried a Lead-Away cloth on my finger to rub the inside... still black.

    Then early this year I bought a bottle of Shooter's Choice Extra Strength Copper Remover for a rifle I owned.
    Just as a test I packed the AK brake with paper towel and soaked with the Shooter's Choice.
    To my amazement after a short soak the inside of the brake was down to the hard chrome and almost all the black was gone.
    I tried this inside the chrome lined gas block with the same results. All the carbon was gone down to the chrome.

    The Shooter's Choice Copper Solvent is not listed as a carbon remover but sure seems to do the job.

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    Senior Member jet3534's Avatar

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    I would be afraid to use the Shooter's Choice Copper Solvent having always heard that Ammonia will damage Chrome.

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    Administrator Krupski's Avatar

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    Quote Originally Posted by jet3534 View Post
    I want to try cleaning an AR Bolt Carrier Group in an ultrasonic cleaner using a water based solution. Would putting the BCG in an oven (at say around 200 degrees) after cleaning be sufficient to remove all water residue? I see people using an air compressor to blow dry parts after ultrasonic cleaning, but I don't have an air compressor. Also, is it totally inappropriate to use even a very small quality of protective lube such as CLP on a gas key after ultrasonic cleaning? I have really done very little shooting with an AR, so I don't have much of an idea about how resistant they are to corrosion. I have to say that after many years of AK shooting, I now prefer the AR ergonomics. Not sure why. I guess it is sort of like one's taste in music can change.
    What I do to clean the inside of the bolt carrier is to take a regular AR "lug and chamber" brush (one of these):





    ...and use it to clean the bolt carrier. The small part goes into and cleans the firing pin tunnel and the large part scrapes away all the carbon crap inside the bolt carrier.

    The small part needs to be forced into the firing pin tunnel when it's new, and then it's no good as a lug / chamber brush, so set aside one for bolt carrier cleaning and don't use it for anything else.

    Anyway. then I just run a few patches with Hoppes #9 through the bolt carrier, then re-assemble the (already cleaned) bolt, cam pin, firing pin, etc.. and stick it back into the rifle.

    BTW, I leave the parts wet with Hoppes #9... it soon evaporates and leaves a nice even film of oil on all the parts.

    Concerning the gas key... why not lubricate it? Jeez, it's just a rifle. The worst that can happen is you get a blast of oily smoke in your face when you first shoot your freshly cleaned rifle.

    The ONLY thing you need to even remotely worry about is ammonia based copper solvent debonding chrome plating. The ammonia does not itself hurt chrome, but chrome plating is usually applied to a base plating of copper or copper and nickel (for better adhesion). The TINIEST pinhole or defect in the chrome plating will allow solvent to get under the chrome and attack the copper (which is holding the chrome on). No copper plating and the chrome peels off. Not good.
    Last edited by Krupski; 11-02-2017 at 10:24 AM.
    Gentlemen may prefer Blondes, but Real Men prefer Redheads!

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    Bolt carriers are HARD chrome plated.

    Only decorative "bumper" chrome is under plated with copper, then plated with bright nickel, then plated with chrome over that.
    That's why decorative chrome will bubble up and peel off, showing rust under it. Moisture can infiltrate under the layers and attack the steel.
    Ammonia can damage decorative chrome and bright nickel by penetrating to the copper layer and attacking it, which lifts the top layers.

    Hard chrome is plated directly to the base steel and actually bonds into the steel pores.
    Ammonia might damage it if left to soak too long, but the amount in a bore solvent would take a pretty long soak to damage hard chrome.

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