More on EMP Protection

Tin can with friction lids


I have recently spent more time on EMP research and testing and have come to several conclusions.  The way I am now testing my Faraday cages is by placing a cell phone inside and seeing if it will ring.  This has lead to some interesting results.  The first thing I found was that the use of a microwave oven for a Faraday cage is very questionable.  They will not block a cell phone transmission.

A 50 cal military ammo can lined with styrofoam with the rubber seal still intact was successful in blocking cell transmissions.  I have always been told to remove the seal or it won’t work.  Another thing that I tried was a tin can with a friction type lid lined with a non-conductive material, similar to the cans you buy popped popcorn in.  These worked well.  You may want to sand the inside of the lip of the lid to make sure you get good contact.

The last thing that I tried was the Faraday Bag distributed by TechProtect.  This is a Milspec bag and seems to work well.  It blocks cell phone transmission.  I talked with the owner and saw a video of one of the tests he ran on the bags.  He placed a cell phone inside a bag and placed it in a microwave oven.  He then turned the oven on.   It made a nice light show.  When removed from the bag the phone still worked.  He then placed the same phone in the microwave without the bag and turned the oven on.  This killed the phone.

Faraday bag by TechProtect

Based on these results of these tests and the advice I received from TechProtect.  I am double bagging everything.  The TechProtect bags while looking similar to a normal Mylar bag have some definite differences.  They are thicker and have an anti static coating on the inside.  In addition, they are ziplock.  This lets you take out and use your electronic toys and put them back without damaging the bags.  The bags come in various sizes.  They run from sizes small enough to house your cell phone to big enough to protect the tower to your computer. The prices are affordable, when you consider the value of your electronics.

See also  Century Fuel Products Tri Fuel Generator Conversions.

For my own electronics, I am placing the most critical in one of the Faraday bags and then inside a second container.  The choice of the second container will depend on size.  Sometimes this will be two of the bags.

I now feel comfortable that I have a system that I can have faith in that my electronics will survive.  The bags are available on the internet or you can purchase them through DisasterStuff, their link is on the right side of this page.


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17 thoughts on “More on EMP Protection”

  1. Matt in Oklahoma

    the microwave is interesting because the old signals would be blocked but with 3-4g it goes thru now. I dunno what to believe for sure and i really dont have much that i dont use daily except maybe handheld radios that i can store so i’m not sure how important it is, dunno

    1. Does anyone know what happens to you if you are wearing a battery op watch or carrying you cell phone in your pocket in the event of an EMP? I figure you’re fried if you have a pacemaker internally placed but what about more external items still on your body?

  2. Playing devils advocate here: is the lack of cell signal proof of positive EMP protection? Wouldn’t an EMP be stronger than a cell signal?

    I certainly don’t have the answer, but I’m curious. I read “One Second After” for the first time only a few weeks ago and have been much more interested in this topic since then. I highly encourage anyone to read that book if this is a topic in which they are interested.


    1. Robert
      I don’t have all the answer either, that is why I have gone to double bagging. I figure if one bag or cage will block the signal, two is better.

    2. Matt in Oklahoma

      The issue is very complicated because we no longer know. That last serious testing done was when we had tubes in TVs and the last serious solar was when we had telegraphs so no one really “knows” what will happen. They did a small test some years back but it was very limited and inconclusive and there have been some issues with solar stuff but no huge direct hits. I think that is what makes it scary to many is the not knowing
      All we can do is take educated guess’s and pray for the best.

  3. HI there,

    I’ve been interested in making a couple of faraday cages/boxes and am certainly glad I stumbled upon your blog. My question is, if I simply bought a couple of styrofoam coolers like the ones you see in grocery stores lined them with aluminum foil and secured the top (completely lined with foil top and bottom) to the body of the cooler (lined up to and a little over the lip) with tape do you think that would make an adequate faraday cage/box. I am thinking of buying a few of different size to store a variety of things. Thanks in advance and great blog!


    1. The foil would need to be on the outside so that the electronics are insulated from the foil. Even then I would double bag it. I use metal cans and Faraday bags. You can wrap the items in plastic then foil and then put them inside the cooler covered in foil. The reason I like the metal cans and Faraday bags is the ease of getting access to items you normally use.

  4. Thanks for the prompt reply howard. I’ll certainly follow the advice about the plastic bags and foil wrap before placing them in the containers. For me the reason for styrofoam is that the coolers are cheap and come in many different sizes. I would also only be storing things in these cages that would be used in case of an emergency so not everyday items so it’s more long term storage…the longer the better as I hope to never have to crack open my “rainy day” stores.

    Also I’m thinking of purchasing a solar powered generator. If I simply kept it in the box it was shipped in, wrapped that in foil and then put it with all my other stuff would that work as a faraday cage as well? It is basically a unit in plastic, encased in a cardboard box and then I would wrap that in foil which sounds like a faraday cage to me but again I’m somewhat new to this.

    Thanks again,


  5. This appears to be a pretty hot topic, Howard. Might be a good area to focus on with your future blogging.


  6. Earl in Oklahoma

    I read your comments on Faraday bags. I also have experimented with them and cell phones. They work. A more inexpensive source for the bags is Digi Key electronics parts. They are called anti-static bags. The smaller ones go for 35 cents each. They don’t have a zip lock but you can seal them with tape.

  7. I use a popcorn tin. I figure it’s better than nothing. It does block a cell phone. However on another blog they said it doesn’t block all of the transistor radio waves. I’ll have to rethink my faraway cage

  8. My mother in law asked me
    If you have a carport that you framed in with all metal would it keep what ever is in it safe from an emp and when would it be safe after the emp to remove the items and it not be damaged?

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