Protecting Electronics in Metal Military Surplus Ammunition Cans- Part 4, by J.T.

In this article series, I am sharing a better solution for protecting sensitive electronics stored in a Faraday cage made from metal military surplus ammunition cans. Parts 1, 2, 3 provided instructions on how to build the cans. Today, I will share more about how I use my cans and also offer some enhancements that can be added.

Using These Cans

Inside each can are silica gel dry packets ^[1] to keep the inside dry and to prevent corrosion. A florescent paint symbol discreetly marks each of the cans. A label on painters’ tape for eases identification. Only the trickle charger for the Emergency Battery Bank is connected to the household electrical service.

1. Emergency Local Communication

This can contains a 50 Watt Quad Band Yaesu FT-8900R ^[2] radio for emergency local communication. It is powered by two 7.5 amp hour batteries but with internal PowerPole connectors that may also be connected to the larger 140 amp hour Emergency Battery Bank (see below), plus a rollup j-pole antenna and LED flashlight with rechargeable batteries. All of these are included in this can.

2. Emergency and Regular Use High Frequency Communication

My high frequency communications can contains a 100 watt Yaesu FT-896D radio with SignaLink USB for digital communication. Additionally, the can was able to accommodate a LGD tuner. The 12-volt Emergency Battery Bank powers the radio. The power supply may also be used if 120V is available.

3. Emergency Battery Bank

My emergency batter bank can contains four 12-volt 35 amp hour AGM batteries, including a Noco charger to trickle charge and maintain the batteries. (I also keep a backup charge unit, sealed in a Mylar bag, in the Solar Power can. An EMP will fry the charger) The can is very heavy and requires two people to tote this around, since it weighs in at about 110 pounds.

4. Solar Power

My Solar Power Can contains one solar charge controller, a compact distribution box for six 100 watt solar panels, and the meters to monitor each component plus a some PVC connectors, wire and diodes, and my HF 120V 35-amp power supply. Six 100 watt Renogy PVC panels charge the Solar Power Can. However, there are other, better, and tested solar power products that are worthy of consideration and use. These PVC panels are stored in a shielded metal cabinet, shielded to some degree using Laird shielding products. It’s likely that another good article is needed to describe how this product was used to shield these PVC’s in the metal cabinet.

5. Computer, Data and Digital Information

The Computer, Data, and Digital Information Can contains an old but reliable 15” Windows 7 laptop with new hard drive, spare battery, and power cord; an iPad ^[3] with lots of documents and books stored in Amazon and iBook applications; a backup hard drive; DVD and CD disks to restore operating system and key programs or applications; and password protected thumb drives with important personal documentation, including the SurvivalBlog thumb drive with the full blog archive for reference in the future.

6. Electrical Equipment and Backup Parts

The Electrical Equipment and Backup Parts can contains a couple of volt ohm meters ^[4], a small weather radio ^[5], a rechargeable battery charger, a few backup parts for my Honda Generator ^[6], handheld GPS units (one that I use on my road petal bike and the other is an older model Garmin for hiking), the backup NOCO Genius trickle charger ^[7], a Kill A Watt meter ^[8], a couple of handheld VHF/UHF radios with extra batteries and charging equipment, and a 10 watt PVC battery charger. Most of the parts are packaged in their original cardboard boxes or insulated from the interior walls of the ammo can.

7. Inverter

The Inverter Can contains a 2,000 watt modified sine wave inverter, a few meters to monitor input and output, an 80 amp circuit breaker for use between the inverter and battery bank, a PowerPole power strip, extra fuses for the inverter, a 4 gauge wire ^[9] to connect the inverter to the Emergency Battery Bank, and a LED flashlight with spare batteries.

8. Inductive Cooktop

Don’t laugh! One can  holds a 1,200-watt induction cooktop. Connect the inverter  to the Emergency Battery Bank with the 4 gauge battery wires. (Remember, the shorter the wire the better and with the modular can design these cans can be set very close to accommodate shorter cables and power cords.) Amazingly, this cooktop draws less than 2,000 watts on startup. And it boils a quart of water in less than seven minutes. It’s the perfect setup to quickly cook food and boil water. We use the Emergency Battery Bank and the induction cooktop for camping and cookouts or picnics. But you must have the right pots and pans to cook with induction cooktops.

Enhancements to the Shielded Ammunition Cans

Rubber Feet

One of the annoying issues about the ammo cans is that they have no “feet” and it’s not good to have these cans resting on a concrete or hard surface, especially in the basement. The bottoms seem to rust quickly, leaving rust stains on the floor or carpeting (not a happy wife). They also have a tendency to scratch up hard wood flooring. One of the enhancements that has been valuable is the installation of rubber feet on the bottom of each can. These “Made in the USA” rubber feet have a metal insert to maintain the shielding effectiveness. To install, drill four holes in the bottom corners of the can. (Make sure they line up with the top of the lid for ease of stacking.) Then install these feet using the appropriately-sized steel bolt and lock nut.

The secured rubber feet will keep the interior of the can impervious and resistant to electromagnetic radiation. To maintain the water and air tightness, use a very small amount of silicone caulking adhesive ^[10] to ensure a good seal around these rubber feet. I tested these rubber feet by filling the can with water and then letting the can sit overnight. I found no drips or leaks in the morning, which was impressive results.

Interior Compartments

Another enhancement is using high density polyethylene sheets and drawer slides to make and assemble interior components (e.g., shelves, drawers, and compartments) to make it easy to store, insulate, and remove equipment from each can. For example, the UHF/VHF radio described above is mounted on a ¼” sheet that have soft close draw slides. To use the radio, lay the can on its side and pull the radio out on a shelf. At other times it stays firmly connected to the shelf. This enhancement makes it very easy to get to the back side of the radio or make any needed antenna and power connections. This seems to be another opportunity to write an article that describes how resourceful someone can be to design and build these components inside these ammo cans.

Summary

The described sheet metal gasket with tinned cooper mesh tape is an effective, durable, and reliable solution. You can convert most military surplus metal ammunition cans into a very nice Faraday cage and container. You can easily open and reseal the cans without damage to the integrity of the gasket.  They also keep the interior of the can dry and air tight.

Cost

The cost to make and install the gasket is very reasonable. The raw cost of materials for each gasket is in the range of $8 to $15 dollars, depending on the size of the gasket and the desired “belt-n-suspenders” to enhance the effectiveness of the gasket and functionality of the ammo can.

Required Skills and Time

The skills to make and install the gaskets are easily within the reach of most resourceful people and with tools generally found at home or around the neighborhood. The gasket build requires minimal skills. Given the cost of materials, you can likely mess up one gasket and not be out much and still have a chance to get the next one built just right. These gaskets can be fully assembled and easily installed in less than one hour.

Great Community Project

Like-minded individuals might make this a group project.  A community might want to build a modular and compartmentalized set of EMP shielded ammunition cans for a variety of emergency and disaster recovery events.

Of course, the litmus test would be to have one of these cans and gaskets tested by someone with sophisticated test equipment. After watching some videos on shielding effectiveness of different solutions and containers and performing some simple tests, I feel very confident that when compared to other professional Faraday cages or shielded equipment that this solution will be one of the most effective in protecting your sensitive electrical equipment from electromagnetic radiation and interference with the proper assembly and installation of the shielding gasket.

See Also:

• Protecting Electronics in Metal Military Surplus Ammunition Cans- Part 1, by J.T. ^[11], Part 2 ^[12], and Part 3 ^[13]

SurvivalBlog Writing Contest

This has been part four of a four part entry for Round 71 of the SurvivalBlog non-fiction writing contest ^[14]. The nearly $11,000 worth of prizes for this round include:

First Prize:

1. A $3000 gift certificate towards a Sol-Ark Solar Generator from Veteran owned Portable Solar LLC. The only EMP Hardened Solar Generator System available to the public.
2. A Gunsite Academy Three Day Course Certificate. This can be used for any one, two, or three day course (a $1,195 value),
3. A course certificate from onPoint Tactical for the prize winner’s choice of three-day civilian courses ^[15], excluding those restricted for military or government teams. Three day onPoint courses normally cost $795,
4. DRD Tactical is providing a 5.56 NATO QD Billet upper ^[16]. These have hammer forged, chrome-lined barrels and a hard case, to go with your own AR lower. It will allow any standard AR-type rifle to have a quick change barrel. This can be assembled in less than one minute without the use of any tools. It also provides a compact carry capability in a hard case or in 3-day pack (an $1,100 value),
5. An infrared sensor/imaging camouflage shelter from Snakebite Tactical in Eureka, Montana (A $350+ value),
6. Two cases of Mountain House freeze-dried assorted entrees ^[17] in #10 cans, courtesy of Ready Made Resources (a $350 value),
7. A $250 gift certificate good for any product ^[18] from Sunflower Ammo,
8. Two cases of Meals, Ready to Eat (MREs), courtesy of CampingSurvival.com (a $180 value).

Second Prize:

1. A Model 175 Series Solar Generator provided by Quantum Harvest LLC (a $439 value),
2. A Glock form factor SIRT laser training pistol and a SIRT AR-15/M4 ^[19] Laser Training Bolt, courtesy of Next Level Training, which have a combined retail value of $589,
3. A gift certificate for any two or three-day class from Max Velocity Tactical (a $600 value),
4. A transferable certificate for a two-day Ultimate Bug Out Course from Florida Firearms Training (a $400 value),
5. A Trekker IV™ Four-Person Emergency Kit from Emergency Essentials (a $250 value),
6. A $200 gift certificate good towards any books published by PrepperPress.com,
7. A pre-selected assortment of military surplus gear from CJL Enterprize (a $300 value),
8. RepackBox is providing a $300 gift certificate to their site, and
9. American Gunsmithing Institute (AGI) is providing a $300 certificate good towards any of their DVD training courses ^[20].

Third Prize:

1. A Royal Berkey water filter, courtesy of ^[21] Directive 21 (a $275 value),
2. A custom made Sage Grouse model utility/field knife from custom knife-maker Jon Kelly Designs, of Eureka, Montana,
3. A large handmade clothes drying rack, a washboard, and a Homesteading for Beginners DVD, all courtesy of The Homestead Store, with a combined value of $206,
4. Expanded sets of both washable feminine pads and liners, donated by Naturally Cozy (a $185 retail value),
5. Two Super Survival Pack seed collections ^[22], a $150 value, courtesy of Seed for Security, LLC,
6. Mayflower Trading is donating a $200 gift certificate for homesteading appliances,
7. Montie Gear is donating a Y-Shot Slingshot and a $125 Montie gear Gift certificate.,
8. Two 1,000-foot spools of full mil-spec U.S.-made 750 paracord ^[23] (in-stock colors only) from www.TOUGHGRID.com (a $240 value), and

Round 71 ends on July 31st, so get busy writing and e-mail ^[24] us your entry. Remember that there is a 1,500-word minimum, and that articles on practical “how to” skills for survival have an advantage in the judging.