What is Cosmoline?

H

Hoppy

New member
Hi,

I'm planning on picking up my Yugoslavian M-48A today and I've read a lot about it being packed in cosmoline. What is this stuff?
I looked at the rifle the other day, it is in excellent shape. There is honey colored oil covering all of the metal working parts. Is this the cosmoline? The stock is very dark but dry. The guy behind the counter says it's teak wood. I've never heard of teak for a stock before, but it's a very dense, sturdy, resistant wood.

I plan on giving the m48 a thorough cleaning, but any additional tips you can provide will help. Thanks!

Hoppy
 
You are right. That honey colored oil is the cosmoline. Its actually a grease. I'm sure someone else here can tell you more about what it is composed of. I just picked up my Romanian SAR-1 last night and it was covered in the stuff. I found the easiest way to clean it was to fill the bathtub with HOT soapy water (I used palmolive dish washing liquid) and let the whole gun sit in it for about 20 minutes. Almost all of the cosmoline came off, and the little that was left i used hoppes and a toothbrush to take care of. Actually worked REALLY well and was super easy. It left the whole gun squeaky clean and ready for a good lubing.

Good Luck
 
One of the more tenacious substances known to man - - -

I think most governments had some similar substance, to protect guns in long term storage.

One of the better ways to get it off is to use the high pressure soap spray at a self service car wash. You might spray the whole thing with carburator cleaner from auto supply store first. Then use high pressure soap spray, and then high pressure rinse.

Depending on where you are, you might want to put the rifle in the bed of a pickup truck or in a wheel barrow, to keep from alarming the populace.

Best of luck,
Johnny
 
Thanks for the tips guys. I'm going to start with a hot, soapy soak I think and go from there.

I just picked up the M48a, it's awesome! I can't wait to take it apart and check it out...and then shoot it. :D
 
Don't forget to try oven cleaner to get rid of the cosmoline. I've done a dozen rifles with this methoid with excellent results.

BTW, the m-48s commonly sported teak stocks. The wood cleans up real nice and with a fresh treatment of BLO or tung oil, they can look outstanding.

Noban
 
Depending on where you are, you might want to put the rifle in the bed of a pickup truck or in a wheel barrow, to keep from alarming the populace.
Click to expand...

Just had a funny thought. My boss's family owns a car wash in Manassas, Va called Sills Carwash. The manager, Bucky Sills, is a gun nut (NRA instructor, board member of local shootin range, I hear his young sons are quite the marksmen, etc).

I'll bet if you handed him your SAR covered in cosmo, he'd hand it to one of the mexicans that work there and let them 'run' it through the car wash for you, literally! Hell, they'll throw in a coat of 'polycoat' for an extra tip..

BWAAHAaahhoohhh huh? well, I guess you had to be there.....:p
 
Just ordered my own M48A today. They guys over on the Mauser board like something called Purple Power degreaser (available at Wal-Mart). I think I'm going to give it a try. Several also recommend "sweating" the rifle in a vehicle on a hot day to get the cosmoline out of the stock.

Elephant snot and monkey flung-dung? Guess I'd better wear gloves. Don't want none of that West Nile virus.

Mauser board: http://pub42.ezboard.com/bparallaxscurioandrelicfirearmsforums

Do a search there. They have all kinds of good info on removing cosmoline.
 
I recommend the "Purple Power" treatment, full-strength. I wouldn't want to use anything water based for fear of raising the grain of the wood. I recently de-cosmolined a Finn M39 in this manner, it worked well but did require quite a bit of the degreaser. Afterwards you can re-oil it with something like boiled linseed oil, or tung oil.
 
Be careful. Be very, very careful...

Some commercial degreasers are caustic and will etch metal. Read the product directions and read the active ingredients before applying any chemical to a firearm. I would also test any chemical on an inconspicuous (and non-critical) area before use.

I'm not sure about the chemical composition of Cosmoline, but I believe it is a self-healing barrier protection coating with a high wax content.

One product I would consider using is called "DeSolvit" (not sure about the spelling); it is made from distilled orange oil (yes, the fruit) and is great for removing adhesive, tar, grease, and other sticky substances. It is a very light oil and has a mild orange odor. I have used it on many items--including a wide variety of plastics, metals, glass, even painted surfaces--and I've never had a surface damaged. (Note, this is NOT true for competing products like "Goof Off.") Just soak a rag and wipe it on (or brush it on), wait for it to work, and then wipe off the gunk.

I think DeSolvit would be better than soaking in water because if you don't get the water completely out of the action (and every other nook & cranny of your firearm), you will end up with rust. DeSolvit, on the other hand, wipes off easily with a soft cloth and at worst, will just leave a light oily residue which will evaporate.

Note: While I have used DeSolvit on many surfaces with excellent results, I have never cleaned a firearm with it. Use at your own risk.
 
Regarding the oven cleaner, I always completely disassemble the rifle before cleaning, so the only metal affected is that which is pinned into the stock. Even so, none of that metal has ever been adversely affected.

Incidently, I only use the oven cleaner that contains no lye. I first immerse the wood parts in very hot water for 10-15 minutes. Then I liberally cover the wood with oven cleaner and let it soak in for 10-15 minutes. Then I use a synthetic bristle brush to scrub the surfaces and every nook and cranny of the wood. I repeat this process up to 3-4 times, depending on how much cosmo continues to leach from the wood. On wet wood, the residual cosmoline will appear as dark blotches. You can address those with spot touch-ups.

Once satisfied with the cleanliness, let the stock sit around for at least 2 days to air dry. Don't be put off by the color of the wood. It will sometimes appear completely bleached out, almost gray. Incidently, I have never had a stock swell enough that a tiny bit if sanding wouldn't fix, and more often no sanding is required. never dry wood in an oven or in direct sunlight - that can cause warping and cracks.

A simple refinish method I use is to rub the dry stock down with synthetic 0000 steel wool to remove the "fuzzies" from the soaking. Regular steel wool has oil in it and is more likely to leave small particles behind. Follow that with applications of boiled linseed oil mixed 5:1 with paint thinner. Rub each coat into the wood with a clean, lint-free cotton cloth. Rub firmly and briskly to heat up the wood.

Do this for as many as 10 coats, depending on how the finish appears to you. Wait 24 hours between each coat to ensure proper drying. On the last coat, apply the mixture with 600 grit sandpaper. This will form an oily paste as you GENTLY rub the wood on this last coat. Once the smoothness of the stock is to your liking, wipe off the residual paste with a clean cloth and let dry for 24 hours.

For a final finish, I then apply a mixture of boiled linseed oil, turpentine and bees wax, melted together in equal parts. Rub this paste briskly into the wood and it will provide a dull, attractive military-like finish - and it smells great too!

Good luck

Noban
 
Folks,

Thanks a lot for all of the info. This is my post cleaning and post range trip report.

I took my m48 completely apart. (I didn't think it had a lot of cosmoline until I got it apart..) I soaked the metal part is very hot water with dish soap as recommended. This seemed to just loosen a little bit of the gunk. So I rinsed them off and decided to start cleaning them with WD-40. The tub was a mess! So, I had to clean the tub. The Scrubbing Bubbles worked wonders on the cosmoline in the tub. It gave me an idea. I brought the pieces back up from the basement, foamed them up with scrubbing bubbles and watched. It would foam up white, eat the cosmoline and slide right off!! This stuff worked great! ( I was worried that it would affect the metal, but it looks great) It got everything off except for some of the nooks and crannies such as the moving parts of the rear sight. I got this off with the aerosol gun scrubber. This rifle is in excellent shape, the bore is blindingly clean and the bolt cycles beautifully.

I thought the wood was fairly clean an dry (it's very dark). I figured I would leave it and someday refinish it, it's teak and should look good with a rubbed oil finish. After shooting about 20 rounds through at the range, the fore end started to ooze. I wiped it with paper towels. Looks like I'll be finishing it sooner than later. Back at home, I sprayed some gun scrubber (this stuff smells like acetone, not sure exactly what it is, but it evaporates quickly the same as acetone.) The gun scubber cleaned the surface of the wood fairly well. I'm not sure if the impregnated grease will come out the same way. Any suggestions will be appreciated.

Finally, at the range. I love shooting this rifle. With the ammo I used it was quite accurate. My groups were about 3 inches at 100 yds. I think it can shoot better since a couple of times I had some connecting holes. The sites work very well. We have steel plates at 150 yds and another at 250. From a rest, I was hitting them consistantly. The 8mm gives a great thump against a steel plate too.

Thanks for all of your help!
Hoppy

Hey, my 100th post!:cool:
 
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