Survival Gear Review: Monovault


By Jimmy C & Murphy from the Team

USA Berkey Filters

Caching Tubes

We have heard of buried automobiles, buses, dish washers, and chest freezers.  Ammo cans slathered with roofing tar are an old doomsday preppersstandby.  Other military surplus items like sonar buoy tubes, 120mm cans and reverse osmosis filter containers are used when you can find them.  Plastic pipe (PVC or ABS typically) works well and can be very inexpensive in smaller sizes, however  in the larger sizes, PVC pipe can be very expensive.  A guy could spend over a hundred bucks on a single 12” PVC end cap.  Such vaults tend to be one time use assemblies unless you can get the rubber gasket fittings and some grease.  Also, time is money.  The time you spend creating your survival cache container is time you could be spending on other preparedness tasks.

A Better Way

All of these solutions involve the re-purposing of something designed for doomsday prepperssomething else….that is until now.  Recently the team at found and tested a breakthrough caching container.  The new containers are called Monovaults and they are designed as an off the shelf caching system letting you spend your time considering the contents of your cache instead of reinventing the caching container wheel.  Also, they are designed and manufactured in the United States by a company out of Idaho called Polyfarms.  The team at Polyfarms is dedicated to preparedness and has really thought through the problems of storing items underground.

If It Is Not Buried, It Is Not Safe

Monovaults: The job of any caching container is to get between your valuable stuff and those elements that would harm it.  To this end, the Monovault system has three components.

1. Container

2. Humidity Control

3. Corrosion Control

First, the Container.

The choice of material for the team at Polyfarm is a rugged commercial doomsday preppers doomsday castlegrade polyethylene vault (that means non-metallic for those metal detector sensitive applications) which is designed for burial with a large opening and spin on “gamma” lid equipped with an o-ring gasket.  This lid seals up tight over and over without tools.  Protecting this lid is a heavy shield cover that serves to run water away from the inner lid gasket and keeps the inner lid safe from mechanical damage.

The shield cover also allows for aggressive recovery ensuring that you doomsday preppers doomsday castleare unlikely to damage anything with your shovel as you remove covering soils.  Once soils are cleared away, the shield lifts off to reveal a clean access to your vault.  The wall thickness of the monovault is about ¼”.  Tough enough to bury but still light enough to pack around.  Polyethylene is less brittle than PVC at lower temperatures and better equipped to absorb the stresses of a frost line in those northern climates.  We can tell you that these things are a lot tougher than they appear in photos or even in person.  You have to actually get your hands on one to appreciate the toughness of the construction.

Second, Humidity

Humidity control is a must for all survival cache containers.  All plastic doomsday preppersbreathes at some very low level.  A desiccant is a key component of the caching system.  The desiccant adsorbs (This is not a typo, Adsorb is different from absorb) the moisture in the vault at the time of install and stands by to adsorb whatever moisture may migrate into the vault during the caching period.  The system included with monovault mastercacher system comes equipped with a desiccant with a humidity indicator to signal the need to be replaced or recharged.  The desiccant supplied is rechargeable in a typical oven per instructions on the packaging.  The desiccant supplied should be good for several years without maintenance.  Additional desiccants can be employed for longer term applications in the monovault. Note: You can buy the Monovaults separately or buy what is called the Master Cacher System which includes the Monovault and all of the environmental proof bags and dehumidifiers.

Corrosion Control

Corrosion Control refers to the use of Vapor Corrosion Inhibiting doomsday prepperstechnology or VCI.  The monovault system uses VCI bags infused with a special chemistry that out-gases from the bag and protects metal surfaces with a one molecule thick layer of corrosion inhibitor.  The VCI compound flashes off immediately upon removal from the bag.  The VCI bags supplied are rated to perform for up to 5 years.  Your monovault system will also come with one or more special double layer bags (the second layer being an outer metalized barrier) rated for up to 20 years.  The longer your monovault is left undisturbed, the longer the VCI is likely to perform.

Designed with firearms in mind, the monovaults presents a turn-key doomsday castlesystem for long term storage.  Put your gun in a bag, the bagged gun in the vault, and install the desiccant in the vault outside of the bag.  Ammunition, parts, and accessories can be stored the same way.  The mastercache 212 universal kit used as a basis for this review stands about 12.75″  inches tall and 13” in diameter.  It fits many pistols, freeze dried food packs, water, survival tools, shelters, and warm clothes.  The monovault comes in several different sizes including the largest model called the 248 which stands 47.75″ and weighs 18 pounds.

Whether standing by as a grab and go emergency kit, tucked away in a doomsday prepperscrawl space, or buried along your bug out route, you will find the monovault a fast, easy and convenient way to get you and your family prepared.

It goes without saying that where firearms are concerned, you want to take precautions that they do not fall into the wrong hands, especially those of children.  Be aware of  Federal, State, and local regulations of firearms as they apply to your storage applications.  Polyfarms does make a locking system for the top of your monovault but it is not designed to be buried.  The monovaults can be found at

All Photos & Video by the Team


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19 thoughts on “Survival Gear Review: Monovault”

  1. I've wondered about "junk bunkers" for a while, but am at a loss for answers when it comes to who in my circle should know about it, and how to identify the location.

    The vulnerability of the cache means it could be easily raided, intentionally or by accident. As all serious geocachers know, even very well hidden geocaches are stumbled upon occasionally, and unintentional finds draw immediate and intense curiosity.

    The "who" question is a big one. Hiding a sophisticated prep from all but the very most inner circle is risky. And in this case, especially if firearms are involved, the prep could turn tragic. I've wondered about a messaging system that would reveal the cache when needed, but it still requires more luck then I want to throw at this option.

    Regarding the mapping of it's location, and given that TEOTWAWKI has been scheduled for a night delivery during the second blizzard of the season, I think GPS is out, and compass triangulation is a luxury I cannot afford. So that leads a map or relationship to easily identifiable object; one you can see with a flashlight. Which, in turn, then severely restricts the number of locations. Hmmm.

    What do you think? Thanks.

    • I recently had the idea of planting something near the cache that would be fast growing, low maintenance, and easily recognizable. Then once you find the plant all you have to remember is how many paces, and in what direction you stash is buried in. The only plant off the top of my head that fits the bill is bamboo, but I'm sure the botanists out there know of other, possibly more subtle, options. As an added bonus the plant itself could offer some kind of utility or food source… It sounds like a good idea on paper, but I have not tried it or heard of anyone doing it.

      • Plant some ground cover like I have and you can easily burry a cache in the cover and not forget where it is and nobody will ever see it. An idea I have had for sometime and going to put it into action. 4 acres with lost of landscaping which I have is just the right thing I believe.

      • Bamboo can take a while to grow, then it can explode and darn near take over an area if not kept in check… Your cache will be hard to locate if there is bamboo everywhere

    • I think that whatever you do, you need to give a lot of thought to who you let know about your cache and where it is stored. I am reminded of a story an old friend told me about the day his Grandmother passed away. The family was gathered together at her bedside and as she went to her eternal reward she spoke her final words, "I moved the gold from behind the fireplace …" They never found it.

      With that as a cautionary tale about potential problems with keeping things too secret I think that one should make sure either that they keep a small circle of friends in the know, or at the very least let it be known to a small circle of friends/heirs that they have a place where they keep information that can be used to find where their stuff is stored in case of their demise.

  2. Interesting article. My father was a sapper. I remember when he had to disarmed a bomb from WWII times. He always stay calm. Realy impresive.

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  3. Cool product. Just like a time capsule. Does anybody have a list or suggestions on what to put in it? I know weapons and ammo are a giving, MRE? I know this sounds dumb. Duh.

  4. I've planted several caches with guns, ammo, etc on my property. Only I can find them. They are all very well hidden – no way to know anything is there. Not only are they buried fairly deep, but they have large flat rocks on top, so that if anyone tried to dig them up, they would hit rock first. The biggest problem is that if/when I die – they will be buried for a VERY long time. I suspect that folks will be finding caches of firearms hidden all across America for centuries to come.

  5. This is a great product and idea. One must keep in mind that prying eyes and ears of a corrupt government sees these comments. Therefore please don't give out the ideas. While hiding the very things that the anti-gun and anti-constitution law breakers will be looking for when it come to that point. Remember, use your own God given ideas. Be very selective when going about finding the right and safest places for your stasches. Take the time and think it through well. Remember also when it comes to who you select in your circle of friends and relatives that you only select those who are very strong willed and won't break under pressure. Have not only a plan A, but a plan B & C as well. Don't hide all your eggs in the same basket. That's why you need more than 1 of any type of weapon as well as ammo. Also never burry it on your property. So be creative in what you do. They have dog that are trained to sniff guns and ammo out. Red pepper and chyene pepper should be scattered around in the general area but not on top of the site. The pepper will destroy the senses in the dog's nose, and that will end that. Any prepper should have lots of it on hand it the event you are being tracked by dogs. They enemy also has metal detectors as well. So burry the staches deep and scatter lots on nails throughout the entire area. It's important to keep in mind when using the nails to try and do it in a pattern that will lead any search parties away from the stache. Like I said, be VERY creative. You have lots of time to think these things through carefully. When purchasing the items that will be looked for by the constitutional law breakers, try and purchase only with cash.


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