I am moving to a new house with space in the garage for a combination workbench and reloading bench. I would like to use some of the space under the bench to store .50 cal USGI ammo cans that contain cast bullets, reloading dies, some loaded ammo, etc.
Is it best to lay a sheet of 3/4" plywood down on the floor or use a couple of runners cut from 2x4's so that air can circulate under the cans ? It should be a dry environment but i would hate to find rust stains on the floor at some future date.

In my experience, if there is any exposed metal it will be subject to rusting when left long term on bare concrete. Further, if you are sliding the ammo cans across concrete, you will scrape off paint eventually. Sooooo, if you want to prevent rusty bottoms and stained concrete, some sort of separation between box and floor is a good idea.

Froggie

Good advice!!

I have about a 1/2 dozen M2A1 and M19A1 ammo cans in my garage. They have set on a shelf for well over 10 years and I have never noticed any rust on them yet. Summers here are very humid. If I were concerned about the bottoms rusting I would put them on a shelf or paint the bottoms.

I went to Tractor Supply and gota 3/4 inch rubber mat that is meant for horses in stalls..Got the large one when it was on sale for about 30 bucks. A word of warning though..dies and such will have a tendency to rust in the ammo cans.so put some silica gel packets in with them. But I lived in an extremely high humidity area back east. I happen to have about 50 of the ammo cans left and store a lot of cast and jacketed bullets as well as lead ingots I made up in the past. BTW when loaded with bullets or just lead ingots those cans get very heavy. I have 2 or 3 that are full of loose 45 autos that were loaded on the Dillon 1050...also heavy

Concrete with the lime, moisture, and bare metal are a recipe for rust.

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Paul
S&WCA #2726

Froggie is right. Same as my experience. Bare concrete is a moisture sponge and the paint gets scuffed of the can bottoms. You'd probably be ok if your concrete is sealed or if you have one of those high tech epoxy finishes. Most of us don't . . . .

For a while I used 20 mm cans. They hold a lot more than 50 cal cans. That's both good and bad. It seemed like a good idea until they needed to be moved.

Just a note about ammo cans. The "surplus" ammo cans I have bought over the last 40 years come in 2 varieties. The real Ammo cans and cans that are for mining! The mining cans can be Army green or other colors, and have 4 1/8" holes in the bottom to let liquids drain. YOU ABSOLUTELY DON"T WANT THESE!

Ivan

I would suggest plywood and carpet samples, available at floor/carpet stores, to protect from moisture. I have had rust problems in my garage with a portable bench press, vice and a piece of steel rust while resting on the floor. However, I remember reading about protecting those tools by placing plywood on the floor and a large piece of carpet samples on top of the plywood under those tools as a barrier between the bare floor and metal. After scrubbing and soaking the effective rust areas, I set the tools on the plywood and carpet samples. So far, I have not observed additional rust and I am in the process of moving to an apartment with a garage and will redo the same procedure as in my former garage. Moisture can effect metal on top of the garage floors and with the for mentioned procedure, I think I have stopped the rust. As far as ammo cans, I would do the same procedure.

Nick

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NRA Instructor\GCA Gunsmith

I have my cans in the climate controlled house. There is tile on concrete so I have cut 3/4" outdoor plywood to line the bottom of the closet. Floor and wall as high as cans are. Drywall will be damaged by shoving the cans back after getting what you want out or put into them. So far so good. Joe

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Behavior Creates Destiny

Concrete is hydroscopic, it absorbs & transfers moisture from the ground. Do depending on the garage construction, may if may not be an issue. Throwing a piece of 1/2" plywood down is cheap insurance.

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NRA Cert. Inst. IDPA CSO

I the Military, our Bunker supplies were Never put on the "Deck".

Wood pallets or metal shelves always held the metal ammo cans.
Some cans even had a static cloth placed between the shelf and can, for safety reasons.

Never stack too high or over load storage units.. !!

Why worry? I have been storing ammo cans on the floor of my garage for years. I have not had any rust problems and if I did it would be such a minor thing it would be insignificant. Anything you put down will make it harder to clean as dirt will get under it. Who cares of a garage floor has stain. You will get that over the years from all the stuff you do in any kind of shop. It is a man cave after all. Most slabs have a moisture barrier anyway.

Store ALOT of full ammo cans, GI and commercial plastic in my concrete floored garage. Humid in Spring/Summer and salt air environment.
All the cans sit atop scrap 2"x 8" boards. IIRC, I also placed some roofing shingles underneath the 2 x 8's.
Nary a problem.

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Ret'd LEO
SWCA #2275

Go to Home Depot, buy a couple furring strips, cut them to desired length, and set the cans on them. They will allow air to circulate between concrete and cans, unlike any "solid" cover.

I put down plywood and a plastic runner meant for use under a computer station. It works well enough but I like the idea of the rubber horse mat suggested by Sheet 028 in Post #5.

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Freedom is never free!!
SWCA #3437

I quite often reload standing up(mostly shotshells) and I use the large rubber pads to stand on too. I also have a couple where I have the lathe and drill press set up. But I don't use the lathe as much these days. Wish I had kept the milling machine though. Those rubber pads work pretty well for lots of things. Harbor Freight also has thinner pads(cheaper) that work fine.

Very few people put down a vapor barrier under the garage floor slab.
.006 visqueen isn't that expensive ... but few do it . Concrete absorbs moisture from the ground and it goes through the slab....do not sit anything metal or paper / cardboard on the floor , it will get damaged by moisture. Plastic storage containers are a good investment .
Gary

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Certified Cajun
NRA Member

I must have a vapor barrier under mine as no problems with ammo cans or some boxes either. I cannot remember as it was 20 years ago when I built the house

I have a large 20mm ammo can that I store at least thirty bullet moulds in. The can sits on a bare concrete garage floor. I've done this for years without rusting or moisture problems. Most of the moulds have a light oil coating and are in original boxes or wrapped in paper.

I have a dozen or more die sets that I no longer use in their original boxes stored in a cardboard box that also sits on a garage floor. They are not protected with a lubricant film other than what may be inside the sizing dies, but I've seen no evidence of rust on the dies.

I'm not being critical of someone that takes extra measures in protecting their stuff as humidity and other factors vary greatly from one storage location to another. I live in North Texas where moderately high humidity is only an occasional problem.

Yeah, you can't get away with that down in soggy bottom Louisiana though. Our darn water table is sometimes just inches under the surface and very rarely more than a foot or 2 down. I learned that the hard way when digging a hole to put my septic tank in and then like a dummy not filling the tank before quitting for the evening.

Instead of going through the effort of accommodating the metal cans, I just use the plastic cans and the big MTM plastic boxes. No sweat at all having them directly on the concrete.

I kept my cans on a rubber, ribbed runner until I moved them to a unused PU Tool box. Even with the rubber ribs facing the concrete, sweat from the concrete caused moisture. Never had rust, but the cans were well painted just in case.

I'm also in the occupied zone, Sacramento to be precise. I do not put ammo, powder or primers or even lubricated bullets in the garage do the the summer temps (100* isn't unusual) and winter moisture.

I store those inside and the rest of my loading stuff in the garage in on a shelving unit. I do have tool boxes on bare concrete and haven't noticed a problem with them.

I have several ammo cans full of lead ingots and ammo. I too thought I was smart to buy the bigger boxes but somehow they got really heavy after thousands of rounds of 223 and 22.

Even a sheet if plywood can trap moisture between the wood and the floor. I put some 1x furring strips down first as someone else stated.

I use a couple of 2x4s for runners and place them on bricks placed about 4 ft. apart. If the load is real heavy you might want to place the bricks 2 ft. apart. Larry

I believe a lot depends on the region lived in. I'm in Michigan, not known for high humidity, and I have had close to 20 of the 50 caliber GI cans on the concrete floor under my basement workbench for at least 20 years without rust. But, I also have a dehumidifier.

Put down a plastic floor mat runner, stack the cans on it’s, then add a full room dehumidifier to knock down airborne humidity. Ammo should be good for a long time.


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My basement floor is now 25 years of age, with about half of it a two car garage, all climate controlled. My reloading room and powder storage is secured next to the garage and those wide ,1/2" rubber belts are an excecellen foor covering for my needs. Easy on the feet, a groundwater or a leaking cooling won't bother my ammo or safes.

I keep metal ammo cans setting directly on the rubber. It stays about 67 degrees in there for the most part and low humidity. Desiccant pacts are good insurance.

My wife says I should just make is a "rubber room", sos. I CAN JUST BOUNCE OFF THE WALL!