Why do some finishes rust so easily?

[DrDragon]

I live in a very humid area, but all guns are kept in the safe with desiccant packs that I recharge when needed. I keep all of my guns clean and wipe a thin coat of Ballistol on after every cleaning, I even wipe them with a gun cloth after handling.

Lately I've noticed little specs of surface rust on 2 specific finishes: the finish that comes on Remington 870 Express models, and the matte (only the matte) portions of the slide on my Ruger SR9 (the rounded areas)...and the Ruger slide is supposed to be Stainless Neither my Beretta, or Glock, nor Blued guns have this problem, nor do my plain "satin" finish stainless guns.

What I don't get is, I have knives that are bare carbon steel, and a few firearms that have bare metal exposed through wear...but I have yet to notice a single spot of rust on these surfaces, they are stored in the same conditions and treated the same.

Are specific finishes more prone to surface rust than even bare metal?? If so, why put the finish on at all? I don't know how to phrase this, but is it the metal rusting, or is it the finish itself rusting as it protects the metal? Can I do something differently to prevent this, or is it just what you get with some of the cheaper finishes? Any info greatly appreciated.

 

[ColtPythonElite]

Why not get a dehumidifier rod? In addition, get a humidity gauge to monitor humidity.

 

[DrDragon]

Been trying to avoid that because I'd have to drill a hole in the safe, but maybe it is time to do it.

 

[oldbear]

Are your desiccant packs dry? If not they can be refreshed in a microwave oven. My area of the country gets very high humidity in the summer, so in addition to keeping all of my revolvers as clean as possible, I also apply a thin coat of Johnson's paste wax as needed. For the wax just rub a small amount on all of the surfaces except the grips, let haze up then buff off with a cotton towel. This will keep your firearms looking great and will help protect them from rust.

 

[Shadow 7D]

um, most finishes like Park, and Blue, work by resisting, and require OIL to truly protect the metal.

Also, are they laying against something that traps or attracts moisture?
consider a goldenrod or low watt lightbulb to increase the temp = decrease the relative humidity.

 

[Deus Machina]

Oil and surface area.

Rub some gun oil or CLP onto them, let it soak in, lightly wipe off the excess.

Matte finishes also rust quicker, because they have substantially more actual surface area than a polished finish. When I make parts in the garage, it will cut down on rust to actually polish pieces, and often looks nicer anyway.

I have steel parts that I've polished, cold blued, and rubbed a little oil into, that sit in a Florida garage completely without rust.

Not all stainless is rustless, BTW. Just less prone. High-strength stainless steels still tend to oxidize.

 

[armarsh]

I have had good success with Ezzox. It seems to be the best in a number of corrosion tests.

Here is one: http://www.6mmbr.com/corrosiontest.html

 

[bhk]

On guns with finishes like the 870 Express, it pays to take them apart, heavily spray the finish with a rust preventative (Breakfree works just fine), wait several minutes, and wipe of the excess. This will allow the preventative to soak into the rough finish and do a good job of protecting against rust. Merely wiping a little oil in the 870's surface does not work because it doesn't soak in deep enough to hit the entire roughened surface. Giving it a good soaking does the trick! And the treatment lasts quite well.

 

[hardluk1]

I grew up and lived 40 years in florida and hunted the swamps there. Only thing I used was breakfree clp and kroil. Never had rust,never. Change what you use now and leave some on the firearm.. I hunted in rain and carried working as a carpenter too. Stainless steel has some amount of carbon in it most times for extra stength, thats what shows rust. Put a magnet on your ss firearms to see if it sticks. If it does ,oil it. Your safe probably has a hole in it in the bottom left near the corner allready. Check it out.

 

[stonecutter2]

On guns with finishes like the 870 Express, it pays to take them apart, heavily spray the finish with a rust preventative (Breakfree works just fine), wait several minutes, and wipe of the excess. This will allow the preventative to soak into the rough finish and do a good job of protecting against rust. Merely wiping a little oil in the 870's surface does not work because it doesn't soak in deep enough to hit the entire roughened surface. Giving it a good soaking does the trick! And the treatment lasts quite well.

I wish I'd done this with my Remington 700 SPS Tactical, it had orangish rust on it after taking it out to shoot the first time. I did oil it, but apparently not enough to soak into the finish (it's probably the same as the 870 finish, or very similar). It was a hot summer day when my friends and I first shot it, and you could see everywhere a hand might have contacted it, it had orange on the finish. I then doused it when seeing that, but i think i'm going to spray it all over with Rem Oil.

 

[trex1310]

Try some Kroil Prevox.


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[btg3]

Matte finishes also rust quicker, because they have substantially more actual surface area than a polished finish.

Higher surface in the extreme, such as powdered metal, in the right air mixture, will undergo rapid/voilent oxidation in the form of burning or explosion, given a source of ignition. Regardless, surface area is a key factor with regard to oxidation under any conditions. Rust prevention requires protecting the surface area from air/moisture. Penetrants that with low volatility will do a good job. Sealants can also be effective, but may seal in air/moisture if there is any significant porosity or other surface roughness that can't be contacted. Thus some folks will apply sealants with heat to improve wet out (penetration) of the sealant and drive out moisture. Why not just use a good penetrant which displaces water?

 

[jimmyraythomason]

Why not just use a good penetrant which displaces water?

This. I keep a cloth saturated in WD-40 for wiping down the surface and anywhere else I can reach. I have high polished blue as well as matte blue and yes the matte requires more attention. Rust is none-existant on any of my guns.

 

[DrDragon]

Thanks for all the great info guys. I am definitely going to change up how I oil my guns after cleaning. I almost always apply oil and immediately wipe clean, from now on I will try letting it soak a bit before wiping.

 

[gym]

The only thing I can think of after 17 years of no rust in FL, Is we keep our AC turned down to 73-74 tops. It seems to be the only thing that makes sense. I have had inexpensive safes forever the only thing that differs is that we keep the house cold.

 

[Shadow 7D]

WD-40 is NOT a protectant, it's a WATER DISPLACER

it dries quickly into a gummy mess, it's MUCH better to use something that PROTECTS the metal, stuff like EZ-ox or even MOTOR oil, it's designed to absorb free radicals and prevent oxidation. Wonder if that means Wheat Germ oil would be good.

 

[jimmyraythomason]

WD-40 is NOT a protectant, it's a WATER DISPLACER

it dries quickly into a gummy mess, it's MUCH better to use something that PROTECTS the metal, stuff like EZ-ox or even MOTOR oil, it's designed to absorb free radicals and prevent oxidation. Wonder if that means Wheat Germ oil would be good

Believe what you want. WD-40 serves this purpose VERY well. It does not dry to a gummy mess and has kept my guns ,tools and other equipment rust free for close to 40 years. This is getting very old! Moisture is the primary cause for the formation of rust. WD-40 removes that moisture.

 

[jimmyraythomason]

OP,here is a cleaning/rust preventitive clinic from Brownell's Inc. Brownell's knows a thing or three about firearm's finishes and how to protect them. <http://www.brownells.com/.aspx/lid=10700/guntechdetail/Gun_Cleaning_Clinic__Knowing_the_Limits_of_Rust_Preventatives>

 

[Murphy4570]

I use motor oil and heavy bearing grease to keep engine blocks in my non-temperature controlled shed from rusting into useless hunks of iron.

I don't see why it wouldn't work for long-term firearm storage either, especially if they are kept in extremely moist/humid environments. Grease is a bit messy, of course.

 

[tekarra]

If there is a small hole in your safe, run an electrical cord through it and install a 20W light bulb. It will keep the safe dry.

 

[orionengnr]

+1 on Eezox.

 

[Demon Barber]

I use T-9 Boeshield on all my firearms and machine tools. I spray it on (aerosol can) or dip, let sit a while then wipe the excess off. It displaces moisture and leaves a protective, waxy film.

 

[Mike1234567]

Actually, a small vent at the bottom and one at the top with a light bulb or small heater (as tekarra suggest) will work pretty well. The more humidity then higher the wattage.

 

[drcook]

Those gunsafe dehumidifier rods can actually be bad for firearms. My friend had one in his safe and it sucked enough moisture content from a Shiloh Sharps with a pewter forearm tip to cause the wood to pull away from the pewter tip.

They are ok for metal guns, but you are taking a chance with finely fitted/inletted custom wood

 

[bhk]

Those gunsafe dehumidifier rods can actually be bad for firearms. My friend had one in his safe and it sucked enough moisture content from a Shiloh Sharps with a pewter forearm tip to cause the wood to pull away from the pewter tip.

They are ok for metal guns, but you are taking a chance with finely fitted/inletted custom wood

Sure hasn't been my experience. After a good two decades of use, the Goldenrod in my safe hasn't caused any problems with the finely-fitted wood stocks on my guns (forend cap or not). I have never read of this being a concern either. Makes me wonder if the stock on your friend's Sharps was improperly cured to begin with (?). Shiloh is a good company, though, so it would be surprising. Also, does your friend live in any\ area with extremely low huminity? I suppose a Golden Rod could compound that situation.

Anyway, I have zero hesitation about continuing the use of my Goldenrod. It has worked superbly and caused no problems at all.