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Submerging an Ammo Box


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On my day job we do high reliability pressure sealing, not permitting helium leakage down into -9 exponential range. (Thats pretty darn tight, and they hold pressure for sometimes 10 or 15 years) (Can't really say what). Anyway we seal the product with "O" rings and we grease them with a very sticky grease that puts me in mind of wheel bearing grease. Brake fluid might do the trick, there are rubber parts in brake cylinders , but I'd really trust the grease more. It doesn't damage other things.

hairball

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Not that youd know anything about that...;)

 

For the most part, I don't. I'm a diesel mechanic. Big Rigs use air brakes. Fluid in those systems = problems.

 

But I did help my buddy bleed the air out of his brakes once (I worked the dummy end, stepping on the brake pedal). It squirted out, and he get got splashed a little. When we were done, we were talking, leaning up against his hood. The next day, he had spots on his hood, from the droplets of brake fluid that was on his clothes.

 

Horrible, but funny.

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If you mix the wrong brake fluid with the wrong rubber parts you get swollen deformed rubber parts.

Brake fluid on the seals of ammo cans will probably seal very well, for a short time. Then the seals will tear or turn to goo. Not to mention what it will do to the paint on the can, followed by rust.

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I once had a cache in an ammo box hidden underwater. It took a good bit of weight to keep it from floating- about 2/3 of the space inside the box. I never really had any moisture problems other than a few drops of water seeping in after several months, but the contents were double-bagged and stayed dry. As for condensation inside the box, as long as the seal is airtight and watertight, and no liquid has dripped into the container when it was opened, moisture can only condense from the air trapped inside the container when it is closed, which isn't that much. Bodies of water actually heat and cool much slower than the atmosphere, so although that water may feel cold, a submerged cache is actually subject to less extreme changes in temperature than one exposed to air.

 

I would give several test containers the "bathtub test", or find a pond or similar area where you can submerge a few of them for a month or so. After that long, if the seal is bad, you'll know...

Edited by DavidMac
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The underwater case for my digital camera came with silicon grease.

 

I think that's just what you need. You should get this stuff at a local scuba store, there you might even find some better and more expensive case for your project.

 

Or look here.

 

There are quite a lot of underwater caches. Best thing probably is to ask those guy how they did it, no need to reinvent the wheel.

 

GermanSailor

Edited by GermanSailor
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I would stay away from using Brake fluid. All the brake fluid really does it chemically react with the rubber causing it to swell. At the same time it rapidly breaks down the original composition of the rubber causing it to fail much quicker. A better option would be a silicon grease or a plumbers grease that is used on faucet stems. It can be found at any Hardware store in the plumbing isle.

I would guess one of the biggest issues would be the depth of the container and the pressures it will see.

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Forget about brake fluid, toxic, corrosive, hygroscopic.

Silicone grease is the way to go, used in plumbing for O ring lubrication.

 

Ammo box on the other hand will soon rust. Plastic water proof boxes exists. You coud alos make them with big size plastic fittings and tubes used in plumbing. It is designed to keep the water inside so it should work to keep the water outside ! :huh:

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A standard ammo box will need about 5kg of ballast to keep it down: I picked up some old lead pipes from the scrap merchant and flattened them with a hammer to line the bottom of the can.

 

It took a good bit of weight to keep it from floating- about 2/3 of the space inside the box.

 

I found an easy way to deal with this. I Just drill a few holes in the ammo box and it will sink. No need for any weights.

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Make sure the seals are in good shape, I have heard applying some brake fluid on them helps.

Brake fluid? Ouch! Not only is that stuff corrosive, but it is also toxic to aquatic systems and wildlife, and I suspect that the EPA and some state agencies would want to have a word with you if they learned that you were putting something which was oozing brake fluid into a body of water; there are laws about such matters. In any case, such behavior could earn a bad name for geocaching. Lastly, would you really want caches seekers getting a bit of toxic brake fluid on their hands when they open the container? Yuck!

 

Late edit/add: Overall, the best containers for conditions requiring continuous submersion in water of up to about 100 feet in depth, where the contents must be kept completely dry, are Otter Boxes and the other similar brands of watertight submersible plastic boxes with hinged lids. They work great!

Edited by Vinny & Sue Team
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I am use aproximatly 10lbs of weight to submerge a 30cal. ammo can in a river. The extreme weight helps to combat the current. In still water the amount could probably be somewhat less.

I have replaced the container once due to a water breech. After doing a few tests on the container at home, I think the fault was in how a geocacher resealed the top. ie. may have had a blade of grass in the seal.

I tested the new container and restored the cache. (Test the container by filling with water, inverting it on its lid and place in the hot sun. The expanding heated water should not breech the seals).

Edited by zoltig
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One way of keeping an ammo box down is to attach it to a cinder block with a cable and a carabiner. It will float a few feet above the bottom and can easily be detached so the log can be signed.

 

I think the best solution though is to have the cache on dry land and submerge a piece of metal or plastic with the coords to the cache etched on it. No worries about a wet cache and you still have the fun of an underwater cache.

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you can cable the ammo can to something stationary. it makes sense to put abobber on the cable so that when people go to replace your container they can find the cable.

 

it's best to place it so that people are encouraged to take it to dry land to open it, a detail that you might think is obvious but isn't.

 

be sure to double bag everything and don't skimp by using cheap bags. maybe you might even consider an internal lock-n-lock.

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I have found several caches that were submerged ammo cans and the contents were dry.One cache was 15 feet under water!!! It was weighted down with a piece of metal tethered to the bail located under the catch.

The cache owner told me that he tested the can in his swimming pool before placing it..He didn't add anything to the seal.

Numberous times I have opened AmmoCans and heard a slight 'swish' of air. That is because the last time the can was closed, the temperature was alot warmer. That is telling me that the seal was air tight.

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How about some non-metal alternatives:

- Large tupperware container, not the cheap kind. Perhaps find one with a handle to use as a tie down.

 

- Underwater bag, sold in camping or scuba stores.

 

- Reseable canning jar (they come in plastic) where the lid latches on with a rubber ring to seal it. I have found 2 pint ones at a dollar store, but that's not real big. Look in your canning section of a large grocery store.

 

- A Space Bag might also work. They are heavy duty plastic and often have ziplocks.

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USE NO CHEMICALS!!!!! Isn't part of geocaching seeing the area? Chemicals in the water=no good.

If everyone started using chemicals to sink or help hide there caches we would all be in big trouble, the earth is already screwed up enough without people who enjoy the earth(geocachers) leaving a huge mark on it.

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Take a look on www.caminocustom.be/how.htm

this is how i make caches. I have tested them to a depth of 15 meters and they came out dry.

I use body milk on the seal. I hope this is not toxic ;-). Not to keep the container watertight but to be able to open it after it has been under pressure!

Edited by davyvdb
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:)

if you were to label the underwater (ammo can) cache.

is there a way to label the cache so the label won't fall off..

 

has any one found a good way of doing it??

 

:):huh:

 

I have a cache that's been hidden underwater (20 hrs a day) on a tidal flat, for the last six months. It's a tethered vitamin bottle.

 

The label is regular paper (in retrospect, I could have used tyvek from a recycled USPS mailer), printed, and laminated. I used rubber cement and clear packing tape wrapped completely around the container. As far as I know the label is still attached. It might be more difficult to wrap an ammo can. Maybe you should just stencil/paint the label info?

 

Find a "stencil" font to print your label on regular paper. Tape a sheet of acetate over the paper and trace the lines with an X-acto knife.

Edited by CacheNCarryMA
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A standard ammo box will need about 5kg of ballast to keep it down: I picked up some old lead pipes from the scrap merchant and flattened them with a hammer to line the bottom of the can.

 

It took a good bit of weight to keep it from floating- about 2/3 of the space inside the box.

 

I found an easy way to deal with this. I Just drill a few holes in the ammo box and it will sink. No need for any weights.

 

SOMEONE here owes me for a new computer monitor now!...and do you know how much Coca-Cola hurts when it's forcefully ejected through your nose?!? ;)

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USE NO CHEMICALS!!!!! Isn't part of geocaching seeing the area? Chemicals in the water=no good.

If everyone started using chemicals to sink or help hide there caches we would all be in big trouble, the earth is already screwed up enough without people who enjoy the earth(geocachers) leaving a huge mark on it.

 

Oh, dear! Water is a chemical! Oxygen is a chemical. Salt is a chemical. Everything you come into contact with, everyday of your life is a chemical!

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USE NO CHEMICALS!!!!! Isn't part of geocaching seeing the area? Chemicals in the water=no good.

If everyone started using chemicals to sink or help hide there caches we would all be in big trouble, the earth is already screwed up enough without people who enjoy the earth(geocachers) leaving a huge mark on it.

 

Oh, dear! Water is a chemical! Oxygen is a chemical. Salt is a chemical. Everything you come into contact with, everyday of your life is a chemical!

 

;)

Edited by J'nK
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I obviously wasn't talking about water, air or salt!!! Come on! I was talking about brake fluid, paints, hydrolic fluid etc... Stuff like that. Dude you should know better than that. If you don't care about the environment that's not my problem. People that don't care about the earth are the problem with this earth and the reason why global warming will kill us all.

 

I agree completely! Many thousands of years ago, aliens genetically engineered planet killing machines, known to us as "Cattle". These demon creatures were created to slowly destroy a planet by leaking high amounts of deadly gasses into the atmosphere. The destruction of our planet would have been completed long ago, but the aliens didn't count on us having an insatiable appetite for these vile creatures. We must stop the destruction of our planet by these evil fart monsters. Eat a cow today!

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I've got one ready to hide. Just waiting for the spot to get freed up. It's a double ziplock, in a Lock-n-Lock, in an ammo can. I filled the spaces in the ammo can, and the void in the L-n-L with tissue paper, and sunk it for a week. No moisture observed.

 

In general several "semi" permeable "layers" do not make for a waterproof container. As each one leaks so the container at that "level" is compromised, the pressure of the water slowly forces more of it through each barrier. One of the best ideas I saw for a watertight container was a waterbottle with a large diameter screw cap. It keeps water in - so it keeps it out too.

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Alright, perhaps applying brake fluid to an ammo can seal isn't a good idea. I simply stated I heard it works. The guy at the surplus store I bought my cans at suggested it to revive the seal. And I am sure he meant only a thin layer, I doubt enough that it would be "oozing" fluid. Probably not more than found as other chemicals that are used as protective coatings on some newly manufactured things.

 

If someone is so concerned about this little of chemical in the water, pobably better start banning boat motors right away. Yes, I understand clearly that protection of the envoroment is an important issue, but there are bigger battles to fight on this front.

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:rolleyes:

if you were to label the underwater (ammo can) cache.

is there a way to label the cache so the label won't fall off..

 

has any one found a good way of doing it??

 

:blink::lol:

 

~Paint~

 

:)

hmm

 

well i have toyed around with paint

and well i let it dry for a good 2 weeks and then sealed with clear boat water proofer before i put in in the water

and all i got 2 weeks later was a green ammo can.. :o

 

it is in salt water,,

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Laminate the label and then contact cement the lable onto the container. It will also help to cover the holes in the box. You can also lamenate the cood's and use fishing weights to hold it under water. Left one in my fish tank for over a month and the injet printing never ran. I made the paper small enough i could use tarp grouments on the corners.

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People that don't care about the earth are the problem with this earth and the reason why global warming will kill us all.

 

actually, killing off all life on the planet will not damage the planet itself

not that there would be anyone around to care

 

Plastic waterproofs are the way to go - pelican, or whatever - and paint for labelling. Even the 'indestructable' ammo can will rust

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People that don't care about the earth are the problem with this earth and the reason why global warming will kill us all.

 

actually, killing off all life on the planet will not damage the planet itself

not that there would be anyone around to care

 

Plastic waterproofs are the way to go - pelican, or whatever - and paint for labelling. Even the 'indestructable' ammo can will rust

 

It can take an ammo can quite a while to rust though. I know one ammo box cache that was either submerged or floating on water most of the year and it lasted 5 years. Yeah, it was pretty rusty near the end, but it still kept the contents dry.

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I bought a Otterbox 3000 to carry my gps when camping incase the unthinkable happens, and it would be a decent cache size container, and it keeps all kinds of stuff out, ive put the container through the ropes, and it still never took in any water, dirt, etc. There is another 3000 series container that Otterbox makes, that is a little taller, both the 3000 and the other one would be great for underwater caches, and have a place to attach a chain/rope etc to secure the cache.

Edited by cachenut06
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