Oct92012

57 Comments

Skill of the Month: Make a Faraday cage

When it comes to worst case scenarios, it’s hard to beat the Electromagnetic Pulse (EMP). From my book, Survival Mom:

I�m not ashamed to say that reading One Second After by William Forstchen scared the living daylights out of me. For weeks, I didn�t want to travel more than 15 or 20 miles from home. The novel details life in a small North Carolina town following an EMP, an electromagnetic pulse. An EMP can be caused by the detonation of a large bomb, nuclear or otherwise, in the atmosphere, miles above land. Its pulse wave can easily cover a continent and destroy electronic components in computers, engines, power plants, and solar panels alike. An event like this has never happened on a large scale, and there are differing opinions as to the exact consequences, but one thing is certain: In a matter of moments, life as we know it would be gone forever. Our closest star, the sun, could also do extensive damage in the form of a Coronal Mass Ejection (CME). The results would be similar.

One of the latest hit TV shows, Revolution on NBC, portrays life 15 years following some type of EMP/CME event, and it isn’t a pretty picture. Life without modern technology would be deadly for tens of millions of people. Again from Survival Mom:

Some might describe a post-EMP world as going back to the nineteenth century, but I think in some ways it would be far worse. We no longer have the tools, skills, knowledge, and, in some cases, raw materials to make the most basic tools for survival. How many blacksmiths do you know? Do you happen to own a pair of oxen and a wagon for transportation? You might know how to sew, but can you create cloth from raw cotton or sheep�s wool? The moment of an EMP burst freezes time. The food, medications, supplies, and tools in our homes may be the only ones we have for a long time. If you have 9 bottles of Advil, that�s all you may ever have.

There are so many unknowns when it comes to EMP/CME, but one way to prepare is to build one or more containers to shield important items from the effects of 50,000 volts of power. These containers are called Faraday cages and they’re pretty simple to make.

My friend Rob Hanus of The Preparedness Podcast has spent a good deal of time researching the facts and myths of EMP/CME, and here are his simple instructions for making your own Faraday cage:

The hardest part about protecting your equipment is simply doing it. A few rolls of heavy duty aluminum foil, some cardboard boxes and a galvanized steel trash can are enough to create your own Faraday cage and protect your electronics from EMP.

The simplest and cheapest way to build your own Faraday container is to use heavy duty aluminum foil. By completely wrapping an item in several layers of foil, you can protect that item from damaging effects of EMP. Keep in mind that every side of the item needs to have a minimum of three layers, so by the time you�re done wrapping it in the foil, some sides may have more than three layers. This is fine, so long as you have no less than three layers of HD aluminum foil between any part of the item and the open air.

By itself, these three or four layers of foil are probably enough to protect your electronic gear, but when dealing with an EOTWAWKI scenario, there are no replacements, nor second chances, so it pays to do it right the first time. Simply adding more than four layers of foil to the device is probably overkill and may not add anymore protection than the initial three or four layers. However, you can increase the the effectiveness of your Faraday protection by layering, or nesting them.

For example, place your foil wrapped device into a shoe box or other cardboard box that is wrapped in foil, then place that box inside a galvanized steel trash can with a tight-fitting lid. With your devices protected by three layers like this, they�re likely to survive even an enhanced EMP attack with a stronger electromagnetic pulse.

To get started on your own Faraday cage/container, you’ll need these supplies:

  1. Heavy duty aluminum foil. You’re going to be using a lot of this, so be on the lookout for coupons!
  2. Either plastic wrap (Saran or something similar) or plastic bags for each electronic item you want to shield.
  3. Pieces of cloth that will be used to wrap items.
  4. Cardboard boxes of assorted sizes
  5. Small, essential items that contain an electronic component, such as a clock radio, weather radio, walkie-talkies, ebook/Kindle, mp3 player, etc. Make sure these aren’t things you’ll be wanting or needing in the near future. If you don’t already have duplicates, make a list of what you want stored in your Faraday container and then look for them at garage and estate sales.

The procedure is very simple. First, wrap an item in cloth. This will add a layer that will isolated the item from the foil and will also help to keep any sharp edges or corners of the item from puncturing the aluminum foil. Next, wrap the object with plastic wrap or place in a plastic bag and then wrap with at least 3 layers of foil. Use your hands to gently mold the foil each time, making sure there are no holes or rips in the foil. Every bit of the item’s surface should be covered with at least 3 layers of foil.

Place your wrapped items in the cardboard box and then wrap the entire box with two layers of foil. Layering for EMP/CME is just as important as layering for winter weather! Be sure that no foil used to wrap the outside of the box touches any of the foil within the box. When your box is wrapped and finished, store it off the ground.

If you want to store large items or have numerous items to store, completely line a galvanized steel trash with cardboard. Make sure there are no gaps. The foil wrapped items cannot touch the metal of the trash can. Make sure the lid of the can fits tightly, and you’re good to go.

You’ll find more information about EMP and Faraday containers here.

Be sure to join Rob Hanus for a special Survival Mom webinar on Tuesday, October 23, at 8 CT. He’ll share more information on this topic, address common misconceptions, and answer your questions.

 

There may be links in the post above that are “affiliate links.” This means if you click on the link and purchase the item, I will receive an affiliate commission, which does not affect the price you pay for the product. Regardless, I only recommend products or services I use personally and believe will add value to my readers.

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I'm the original Survival Mom, and have been helping moms worry less and enjoy their homes and families more for 5 years. Come join me on my journey to becoming more prepared to handle everyday emergencies and worst case scenarios.

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(57) Readers Comments

  1. I actually built the one pictured a few months ago, now to just make sure to put ALL the stuff in it…I’m thinking an mp3 player with all kinds of music, alt powered radio, maybe an old notebook w thumb drives holding all our “GNG” info. (I already have this stuff on a drive, just need a duplicate in the can) and another with pics. In the event of an EMP-type scenario, it’s possible that I would be separated (long-term or permanently) from my grown children (sniffle) so I’d want to be able to pull up pics of them and look at them at any moment!

    • I’m sorry Lisa (not the survival-mom-lisa, the person posting above), but a Faraday cage, an old laptop, etc. are not necessary and probably a poor choice for keeping pictures of your loved ones. Print them out on good photo paper and treated well they will last longer than you do. They won’t require power and will not give away your location at night.

      I can read the same books I had as a kid 30 years ago off my shelf, go to a collectable book store and pick up a 300 year old volume to take home, or go to a museum and look at a 2000 year old legible scroll. I try to show a website to my students and the video/image format being more than 5 years old is out of date and “broken”. In my limited experience digital formats and storage media have extremely short half-lives and are relatively unreliable.

      If you are worried about EMPs save hardcopies.

      • I think you both have the right idea. Books, print outs and physical photos are not susceptible to being destroyed by EMP, so having printed copies of important information is a must. However, don’t underestimate the power of having thousands of books and gigabytes of information at your fingertips in digital format.

        Computers (and smartphones, tablets, music players, etc.) are popular because they can easily process massive amounts of information, and provide entertainment. I would much rather do a search through my digital notes and pull up dozens of articles, books, and notes about a topic, with the ability to quickly drill down to what I’m looking for, than to waste potentially hours sifting through one book, then another. I remember doing this type of research in the library as a student and it was painstakingly slow.

        Just think what it would take to print out the gigabytes of preparedness and survival information that I’ve been compiling for well over a decade, and the more than 50,000 digital pictures of my family life.

        Additionally, having access to thousands of novels and short stories would be wonderful after a hard day’s work. Not to mention the joy of listening to music, podcasts and audiobooks while you do chores (those that don’t require you to be alert).

        True, you don’t absolutely need computers or digital information to survive. But, my goal isn’t just to survive, I want to live and thrive as conveniently and as comfortably as possible.

      • Books are great, but are very difficult to transport if you’re trying to keep a lot of references. Consider putting something like a Nook Simple Touch in the faraday cage. They can be rooted to turn them into a regular Android pad and can have thousands of books and other media stored on flash drives.
        Another tip – ground the faraday cage. If you can solder, do this to make a good connection between all the foil layers, then solder a wire to them and plug the wire into a ground connection. This helps drain off the current that can damage electronics and makes it even more likely the things in your safe box will stay safe. If you can’t solder, don’t worry. Buy alligator clips at a store like Frys Electronics or Radio Shack and use that to connect the foil to a ground. And by ground, I mean anything grounded to the earth. Your house pipes and electric systems are generally grounded if your home isn’t really old, and if that won’t work, get a simple grounding rod for $15 or less.

        • See my comment below about the grounding.

  2. Do you have to wrap it in foil if you have a steel trash can with cardboard?

    • Yes. The key is layers of protection. The trash can on its own isn’t enough.

      • Right. The idea is to layer your gear into 2 or 3 levels of shielding. The more shielding you have, the less energy that can reach your device.

        Think of the EMP as being like sound. Let’s say your teenage offspring is loudly playing music in their room. When you close the door to their room, the sound is greatly diminished. This is the first layer of shielding.

        If you walk outside, and close the front door after you, the sound diminished even more. This is the second layer. Now, if your son or daughter is blessed with a really good stereo system and you can still hear it, when you walk into your next-door neighbor’s house, finally, you can’t hear the music. You now have enough shielding between you and the stereo.

        Same exact concept we’re going for with Faraday shielding.

  3. what about batteries? I’m confused as if these would need to be in a faraday cage or not.

    • I’d like to know about batteries too (AA through D) – and what about generators? Are there electronics in the generators that might get zapped??

      • To be honest, we really don’t know whether batteries will be effected by EMP. They weren’t effected in tests in the ’60s, but who knows? The info available is extremely limited. Be on the safe side and store some in your Faraday container.

        Generators: As far as I know, all modern generators have electronics in them. These components will most likely be destroyed. If your plan is to use the generator after an EMP event, I would suggest buying spare parts now and storing them in your shielded container.

  4. One Second After also scared the daylights out of me, but I haven’t known how to do anything about it.

    Please forgive my ignorance, but when would you put the items in the Faraday cage? Do you keep them in there whenever not in use? If you get warning of a bad event?

    • Tammy L., the items you store in a Faraday cage have to be there indefinitely. You can’t take them out and use them, because a catastrophe EMP event would most likely occur without warning. So, anything you store in your cage will need to be extras of what you already use on a daily basis. For example, emergency radio equipment for communication and obtaining information would be great items to store in your Faraday cage. Remember that you need a non-electric way of charging the items that you store, since an EMP or grid failure situation would mean power outage for an indefinite amount of time. Look into a hand crank charger and/or radio combination.

    • Thank you, everyone who gave me that much needed advice!

  5. Tammy,
    The faraday cages can be made and filled now with items that either you will not need until a TEOTAWKI situation arises (walkie talkies, weather radios, etc), OR items that you may have doubles of (e-readers, mp3’s, etc). You can also look for these items as extras at yard sales, thrift stores, etc. Get them ready now with items that you won’t need until then : )

  6. My house has aluminum siding and a metal roof. Am I living in a giant Faraday cage That’d be swell!

    • While the metal siding on your house may reduce some of the EMP, it will in no way eliminate it. For all intents and purposes, you’re just as vulnerable as a house without AL siding. Simply put, there are too many openings in your house that aren’t protected where the pulse will enter.

      Not to mention, everything that is plugged into the wall sockets or has long wires attached (LAN cables, TV antennas, cable TV wires, stereo speaker wires, etc.) will get zapped.

      • Can a room be insulated using layred foil as well

  7. Why try to keep electronics when such an event would take out the power grid that would be used to run them? Better to invest in solar or wind power and stick with the old way of books and printed stuff. We would also be to busy to use electronic gadgets because we would be growing our own food and learning to make everything ourselves.

    • Your solar and wind generation equipment needs to be protected from EMP just as much as other electronics, perhaps more so since they sound like they would be an essential part of your preparedness plan.

  8. Would an EMP ruin an external hard drive? In addition to hard copies of favorite photos, might want to put photos on memory cards and throw a digital frame in the Faraday cage. Shouldn’t take much solar power to make a digital frame function. I love my Sony 10″

    I could see this garbage can solution for storing emergency radios and external hard drives.

    If anything near a “One Second” After scenario were to occur, our society is toast and most of us would very quickly be in very deep trouble. Utility services would cease — sewer and water systems would fail. Disease, starvation, dehydration would occur on such a mass scale there would be anarchy.

    One Second After was the scariest book I’ve ever read. The U.S.A. without electricity cannot sustain a population of 300,000,000 people.

    • Very creative thinking with the digital photo frames.

      While EMP probably won’t have any effect on the disk platter itself, it will fry the electronics needed to operate the drive. That goes for whether it’s an external or internal drive.

      However, there is an issue with long term storage on hard drives that has nothing to do with EMP. Better to store your files on flash memory and make several copies. USB thumb drives are cheap and very rugged.

      A very good point about our society being toast. With a forecast of 90% of the US population dead in 12 – 18 years, it will be the most horrific time this country has ever seen.

      This is probably a good spot to clarify that I don’t advocate the storage of electronics gear because it’s going to be sunshine and lollipops after an EMP event. Books, music and pictures will be great to have and I think you should try to store that stuff, but much of the things you should think about storing are items that give you a tactical edge over those that would try to hurt you.

      Things like: Advanced optics like night vision, perimeter monitoring gear, communication gear (AM.FM, Shortwave and two-way radios), battery chargers, LED flashlights, repair parts for generators (wind, solar, fuel-based, hydro, vehicles), repair equipment like multimeters and welders, and so on.

  9. I must be obsessed with EMP’s. Now I’m reading 77 Days in September. Good so far, and a slightly different slant than One Second After, but still good, and still scary.

  10. Common folks. Think this thing through to it logical conclusion…there will not be radio stations broadcasting. There are some ham radio operators that have backup equipment protected so if you wish to electronicaly communicate that might be a good choice. Cell phones will be a thing of the past.
    Solar panels will need to be protected and all equipment you would like to hook up. Do not live in fear of living without electricity. I have lived without it and the only thing I really missed was an easy light source to light up the night to read, cook, make a trip to the outhouse. I purchased a small solar pannel. And will be using it to recharge batteries for flashlights. After they wear out the transition should be easier than at the first of an event.
    Warning!!! Anyone that’s shows any sign of having a power source will be attracting trouble like a moth to a flame after the grid goes down.

    • Based on a recent email conversation I had, I think there will be radio stations that will be able to broadcast after an EMP event. Technically, you really only need 6, maybe 12, AM stations to cover the entire country. Of course, this coverage would have to come at night when AM signals travel farther. Additionally, without all the RF interference that we have to deal with now, you will be amazed at how far an AM radio station will be able to broadcast. For this very reason alone, if you stored nothing else, you should store a hand-crank powered AM radio in a small Faraday cage.

      Very true about “advertising” that you have power when others do not. However, there are scads of tactical considerations that you need to be aware of, for every and any survival situation. Adapt, improvise, overcome, survive.

    • Solar panels by themselves are not harmed by an EMP or CME. However, the charge controller will be fried. Very difficult to protect a charge controller since it’s connected to the rest of the system (can’t isolate it with Faraday shielding). So, my only option seems to be to buy an extra (500 bucks!) and store it in a Faraday can.

      Also, turning off your system is extremely important if you get a warning. For a CME we should get at least a day’s warning with the SOHO and STEREO sun-watching satellites. There is, however, a real conundrum in a CME: When do I turn my stuff back on? A Carrington type CME will last days, not hours or minutes. I plan to keep my generator shielded during the CME event, then after a few extra days will try that first before turning on my solar system again.

      They make whole house surge protectors for a few hundred dollars. Don’t know how well they protect, though.

    • Now thats a good point, like a illuminated target

  11. The energy delivered via the pulse is looking for an antenna to populate, and from there head to a sink, or ground. In the case of a simple radio, the built in antenna will absorb the energy and deliver it directly to the vulnerable electronics inside. To limit the potential harm, disconnect the antenna.

    Now, the pulse doesn’t know how to discriminate between antennas, power lines, ground wires, cables, etc. Any length of wire that can absorb the specific pulse will do the trick. Even edges of metal sheet can do the job for certain parts of the spectrum. A slit in your shielding can act as a slot antenna, and generate a surge within the enclosure. So, be SURE you are completely sealed. The forces the charge to develop on the outer surface of the enclosure, and prevents it from traveling around the edge of a gap to the inner surface.

    That trash can lid? It may fit “tightly”, but all that means is that there is enough resistance to require some effort to push it on. I gauran-darn-tee you it is NOT a seal. It is only a seal if you provide a crush gasket that will deform in such a way as to contact all of both surfaces during the seating of the lid. And such a gasket is good for only one use. Once you open it up, reposition the lid, make an adjustment… it is junk. Make a uniform band of aluminum using a long sheet of foil folded over itself with some degree of looseness. Lay it over the lip of the can, and force the lid down over it. Try it a couple times so that you can pull it off and inspect how it compresses. If it dislodges and fails to stay on the rim, you will see that and know your can /lid combo may not be suited to sealing. Try a different lid, or reshape what you have.

    YOU NEED A SEAL. Don’t let anyone tell you otherwise…. If it is worth protecting, it is worth protecting RIGHT.

    • A galvanized steel trash is very effective. Using AL foil might make a better seal, but it could also leave a bigger opening if done incorrectly.

      Faraday cages can made from copper mesh, which has holes in it. A 100% solid barrier of metal is not required (same concept as to why you can look into your microwave oven when it’s running), but knowing what size hole is beyond the scope of this.

      The foil WILL stop the EMP. Nested layers of shielding is best (see my comment above about the sound analogy). The trash can, if not stopping the EMP, will greatly diminish what gets to the items inside (which are protected by foil). I don’t recommend using only the trash can for your shielding. For more protection, use more layers.

      EMP is a very strong pulse of electromagnetic (EM) waves. It’s not magic. It’s properties are fairly well known. The EM waves are much like what we use to broadcast AM and FM radio, only far, far stronger.

      Also, do not ground your Faraday cage. This will cause a lot of disconcertion among the electrical engineers, but don’t do it. The EMP also induces voltage and current into the earth. If you ground your container, you could very well be providing a direct path to the items you’re trying to protect.

  12. Is there any way to protect a large solar panel?

    • There is some speculation on this, though. Half the ‘camp’ thinks that the panels would be fine, expect for the blocking diode, and the other half thinks that the whole panel is at risk.

      You could risk it and only shield some spare parts, charge controller, inverter, etc.

      The only way to be 100% certain that they will be functional after an EMP is to completely shield them.

      If you have panels that are in use, you could probably wrap them with copper or aluminum screening, but I wouldn’t know how small the “holes” in the screen would need to be. This screening would also reduce the amount of sun getting to the panels.

  13. I have a large metal cabinet with doors. If I line it with cardboard and wrap my electronics in foil and use metal tape on the doors would that work? I have 2 so I wonder if the one in the basement be better? That give a little extra protection of being underground.
    “One Second After ” scared me to death. I had nightmares and it pushed my prepping even more. Sometimes I see coupons for free blood sugar monitors, I’m thinking of getting some and putting them up.

    • Put an AM radio, tuned to a strong AM station, into the cabinet and close the doors. Do the same for a strong FM station. If the radio can still pick up the signal for either, then no, the cabinets won’t be good to use. If the stations are blocked out completely, then maybe. In that case, I would probably make the cabinet a third-level of shielding.

  14. I’m curious shouldn’t you ground the trash can?
    I’m talking a grounding strap/cable connected to a copper stake in the actual earth?

    • I know it counters everything that we’re taught about electricity, but no, DO NOT GROUND. This isn’t a lightning strike or like any other form of electrical event that you can compare it to.

      Unlike lighting or a shock from an electric wire, during EMP, the pulse is everywhere. And I mean everywhere. It will be in every pipe, wire, cable, antenna, every piece of metal AND in the earth. It will penetrate the earth and induce voltage into the earth itself. This induced voltage WILL be picked up by any metal in the ground.

      So, when you connect your Faraday cage to the copper water pipe, what you’re doing is giving the EMP-induced voltage a direct path to exactly where you don’t want the EMP to be.

  15. So how about making my gunsafe my faraday cage?
    Is a mechanical safe, and bolted to concrete walls in a basement?

    Then add the layers inside it.

    • Does anyone know whether a gunsafe would make a useful faraday cage?

  16. I wrapped some items in 3 layers of foil and then prepared an old metal milk can to keep them in. I think this will work as a f. cage. Nice tight lid also

  17. Um… what’s the point of protecting electronic devices from EMPs if there’s probably not going to be any electricity to charge them, or anyone out there with the capability to put out a radio signal or what have you??? Even if there was electricity I’d be going only on the assumption that other people protected their devices. In all likelihood, there wouldn’t actually be anyone on the other end of the line when or if I could make a phone call. Not trying to be a Debby Downer, honestly. I’m just trying to see it realistically. I would probably try to protect a radio at the very least no matter what on the off chance it did help one day, but I wouldn’t get my hopes up about it.

    • After the shock of an EMP or coronal mass ejection wears off, a world without any form of communication or incoming information is going to be nearly impossible for modern Americans to deal with. If you have even something simple like walkie talkies or a watch that can give you the time of day or an ebook loaded with hundreds of books, manuals, and other resources, all that could make a big difference in surviving, or not. Store a few small solar chargers to make sure you can utilize these tools for as long as possible.

      Regarding that radio — what good will that do if there are no more radio transmissions? Just asking.

  18. Faraday cages must be GROUNDED to work properly. To those who think otherwise, let’s have a quick lesson in electronics:

    EMP (Electromagnetic pulse), is simply a concentration of charged particles. As such, when these charged particles encounter a conductor, they cause an electrical current to flow in the conductor (just like a lightning bolt).

    Unfornutantely, this current flow is usually too much for the electrical circuit to handle, and it can destroy the individual parts of an electronic device.

    By grounding the Faraday cage, you are providing a path for the electrical pulse to energize, and flow AROUND the electronic devices contained within, thus providing protection, since electricity ALWAYS follows the path of least resistance.

    Since any electrical charge would immediately dissipate to ground in a properly constructed and grounded Faraday cage, there would be no harm to anything contained inside, even if it was in contact with the Faraday cage. The cage is simply a tool to provide the path of LEAST resistance to an electrical charge (in this case, EMP).

    A lightning rod works in exactly the same manner as a Faraday cage, and also must be properly grounded to work correctly. It provides the least-resistant path for the electricity to flow to ground, and thus dissipate safely.

    On a technical note, an ungrounded Faraday cage will act more as a capacitor (electrical storage device) than anything, which can indeed cause damage to any sensitive electrical components within, since the electrical current is searching for the path of least resistance, and may end up going through your electrical items within the cage. This may also cause capacitive and magnetic induction which can cause damage to unprotected electrical circuits (induction works similar to EMP, but in this case would be on a much smaller scale). This phenomena is also known as ‘ground loop’.

    Summary: Ground your Faraday cages properly for the best protection.

    For those who have said “DO NOT GROUND” because the earth will be ‘charged’ and the electricity will flow into your ground wire to your Faraday cage:

    Please take some time to learn basic electrical theory. Electric current ALWAYS seeks and flows to GROUND. Period. It WILL NOT flow ‘backwards’ into your electrical components, simply because it seeks homeostasis, like all things in nature. Your ideas about not grounding Faraday cages go against known LAWS of electricity and chemistry. No matter whether you have a positive ground, or negative ground, electric currents will ALWAYS flow to ground when given the opportunity, no exceptions.

    • That’s not the opinion of the EMP experts and scientists. Large Faraday cages for EMP can be grounded (if you know what you’re doing), but small ones, like those you would use at home, should not be. Yes, it goes against what we’re taught about electricity, but if you look into what EMP is, as well as what the EMP experts are saying, you’ll see that grounding EMP Faraday cages is not necessary and may in fact be the exact wrong thing to do.

      I don’t mean to be rude when I say this, but you really need to do some research before you start telling people about something you don’t know anything about. It’s dangerous and irresponsible.

      You can read more about EMP and grounding here:
      http://www.futurescience.com/emp/emp-grounding.html

  19. Thanks for the article. This issue of EMP events needs to be made an issue regularly. People need to know how bad it will be if the grid goes down even in a relatively small region. This should be common knowledge but it is not. Families need to prepare accordingly. They need to be able to make informed decisions. How bad will it be?

    http://beforeitsnews.com/survival/2012/12/out-with-a-bang-how-bad-could-an-emp-attack-be-2454182.html

    Lux

  20. Pingback: Emergency Preparedness - Week 5 "Supplies" | A Bowl Full of Lemons

  21. Thanks for this article. We were wondering about “testing” our small “popcorn” tin Faraday Cages”. My husband suggested using his cell phone. We placed the cell phone in various cans we had around the house. We put it into the can and then tried to call it from our home phone. If it rang inside the can, we concluded that it wasn’t a good cage. We did find many cans that did serve as FC’s. We have tried the larger metal “trash can” type and it didn’t work as a cage for the phone. Perhaps the one we put it in was made of a different type metal. Based on your article we will keep trying. Also, the small “popcorn” tin Faraday Cages have not been grounded–yet.

  22. There are some very fundamental errors in much of what is being said about EMP and Faraday Cages. My best advice would be to purchase the book “Electromagnetic Compatibility Engineering” by Henry Ott. Pay particular attention to the descriptions of how metal enclosures attenuate RF signals and how holes and gaps render an enclosure ineffective. To be an effective Faraday cage the trash can lid must be fastened to the can at intervals of 1/20th of the wavelength you want to be effective down to. Each fastener has to compress the layers of metal together at 100 PSI. Then you will find that the thickness of the trash can itself will only shield RF above a certain frequency. The book will explain why you do not want to ground your Faraday cage.

    The book retails for close to $200, but Amazon usually has some new for $140. I lucked out and obtained a used one for $80.00.

    For interesting reading on EMP testing Google “Operation Starfish Prime” and “Operation Baker.” It’s darn hard to find, but search for articles on Soviet Testing of EMP.

    There is no way I have the time to condense the book into specifics to argue against the errors in these posts.

    I bought the book because I was designing a piece of electronic communications equipment for the Air Force and it had to undergo certain tests.

  23. I was wondering the reason the Faraday cages were not grounded? When an electric charge hits the outside of the Faraday cage the electrons will attempt to become uniform on the outside of the cage, without a ground to make the inside of the cage neutral, wouldn’t the electrons flow to the inside of the cage until the external charge became uniform across the entire conductor? Furthermore if you only grounded the outer layer of the Faraday cage would that be enough? Should all layers be grounded independently of each other or would grounding the inner layers be worse rather than better? I am asking not just as EMP shielding but as if I were sending the entire electromagnetic spectrum at it with several million volts, or for instance if I put an electromagnet on the outside, the foil and trashcan are non-ferrous but would the contents still be attracted to the magnet?

  24. Two things…. First, I just popped over to Amazon, checked out the synopsis, and purchased the Kindle version of One Second After. I love a good book. Second, I’ve gathered a collection of both physical and electronic information. I built the above cage and placed a solar charging weather radio that has USB and assorted tips for charging electronics. The radio charges by hand crank if no sun. I also placed 3, 32 GB, ipod touch 4’s with ALL my family photos, all our personal information (id, income tax, , drivers license copies, birth certificate copies, etc). I did this with 3 because I have two daughters, each with a family of their own. My kids don’t do the prepping thing, but I do for them. One for each of us, EXACT same information, medical, food prep, water prep, shelter, and 3 Scooby episodes and two Disney movies for the grandkids (I never forget the grandkids when I’m prepping!). Once a month or so, I get them all out and update with the new information I’ve found and put them back. The girls know they have their own “BOB” sitting at my house, if they can get to it.

  25. Would any narrow gaps in shielding be susceptible to arcing sparks leading to a fire hazard?

  26. the tin foil would work great but only if the device is insulated from the foil. otherwise the foil will actually enhance the emp and make it more destructive. also any wires left attatched to the device and unprotected will do the same thing.

  27. The comment up there made me wonder – would an old microwave oven work for this purpose? Anyone know?

  28. I have made a faraday cage out of a trash can. When I put a ham radio in the can it will still recieve signals. If I put it in an unlined pop corn can, it will not revive signals. What am I doing wrong with the trash can. I have it lined with card board. Another thought, what about putting the pop corn can inside the trash can?

  29. How about everyone taking good old fashioned Girl or Boy scout classes. Advil? Learn which plants will treat ailments. We need technology to function as a business society, but could survive without it if we are prepared.

  30. Since I have the capability to store fuels and lubricants, I would like to consider ways to protect some of my vehicles so I could get around after an EMP event. Any suggestions?

  31. I bought a solar humless generator w 100 watt solar panels for charging it. It was shipped in a heavy cardboard box w heavy copper staples and 1/2inch styrofoam pieces as package materials. Can I use the cardboard box it came in as a faraday box if wrap the outside with several layers of heavy duty foil and do the inside also? Are the copper/copper colored staples a concern and does it make a difference what side if the foil, shinney or dull, faces towards the inside of the box? The generator is also inside a heavy thickness plastic clear bag. Do I leave the bag on and wrap it in foil as extra precaution? What/how do you suggest prepping my generator from what I have told you? I have not taken the solar panels out of their box yet but will faraday them also. These will be my creature comforts wtshtf. Your input appreciated as I have to get this right the first time without error. Thank you and regards.

  32. I think all the talk of an emp is now futile. With our borders being dropped by the current POS in the whitehouse this country will succumb to disease long before an EMP could do us harm. My advice buy visqueen and lots of n95 masks, along with germicidal soap. You will need them to quarantine yourself inside your house. Also be prepared to shoot anybody who tries to force you out of said house. Lots of air filters as well for the furnace.

  33. Hi TheSurvivalMom, thanks for sharing this DIY faraday shielding device. I’ve always wanted to make my own and I’m really interested about faraday shielding.

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