# EMP Faraday Cage Idea



## Sir Publius (Nov 5, 2016)

I wanted to run this idea past everyone to see what they thought, and hopefully, if people think it will actually work, to spread the idea, since its extremely cheap and easy. I've been buying tins from the thrift store for darn near free, you know, the kind that you might get Christmas Popcorn in. They range from pretty small to probably a gallon size or so up to probably 5-7 gallon size tins, all different shapes and sizes, which is nice. Think that would be a good Faraday cage?

I mean, they are solid sealed metal, although very thin, and the lids usually are a pretty tight fit. They are great for any sort of storage, and I think could store small electronics like two way radio's and such. Also, because they are thin, you could offer more protection by doubling up, tripling up, whatever you want, by putting tins inside of tins for extra protection (all insulated from touching each other of course). 

Any thoughts about whether they would work against EMP or not? If they would, again, you can get them just about for free some places, which is pretty sweet. I can say I have a world SW radio in a case, in a probably gallon tin, then that tin insulated against (not touching) a bigger tin that it is inside, as an extra Faraday layer. Not sure if it would work, but better than nothing I'm thinking. Any thoughts?


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## sideKahr (Oct 15, 2014)

It would definitely work. I would sand away any decorative paint inside the lid and where the lid touches the bottom to ensure a good metal-to-metal contact there. Then tape the seam all around with aluminum tape, not duct tape. Metal enclosures such as galvanized garbage cans and the like reduce RF energy in the 100 kiloHertz to 1 gigaHertz range by 40 db, adequate to protect electronics from EMP. If you used a can inside a can, you should be golden.






Welcome to the forum.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> It would definitely work. I would sand away any decorative paint inside the lid and where the lid touches the bottom to ensure a good metal-to-metal contact there. Then tape the seam all around with aluminum tape, not duct tape. Metal enclosures such as galvanized garbage cans and the like reduce RF energy in the 100 kiloHertz to 1 gigaHertz range by 45 db, adequate to protect electronics from EMP. If you used a can inside a can, you should be golden.
> 
> Welcome to the forum.


Thanks so much. You know, that is something I have wondered about in the past, whether you would HAVE to use aluminum tape around seals. Maybe it depends on how tight the seal is? I know with metal garbage cans, they are so large, that they can be slightly misshaped and have 1/8 or bigger spots where metal is not touching metal, though the lid overhangs the barrel. Not so with those tins if in good shape. They are usually real tight. In fact, I have one metal one the size someone might put sugar or flour in, and its thicker than regular tins, and when I put that lid on, I can't even get the damn thing off, excuse my french. I mean, I know using aluminum tape would be better than not doing it, but HOW much does it help, and is it necessary is what I've pondered.


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## sideKahr (Oct 15, 2014)

It is absolutely necessary to tape the seams. A seam will act as a slot antenna, directing the RF energy inside the can. Without the tape, a metal can even with a tight fitting lid will only reduce EMP by about 18 db. Not good enough to protect electronics.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> It is absolutely necessary to tape the seams. A seam will act as a slot antenna, directing the RF energy inside the can. Without the tape, a metal can even with a tight fitting lid will only reduce EMP by about 18 db. Not good enough to protect electronics.


Hmm. Good to know. BTW, just noticed your screen-name. I have a CW9 myself. Nice little carry in my opinion. I don't have much experience with other companies except for Century (what a nightmare they are) to compare them to, but Kahr is by far the best firearm company I have worked with, customer-service-wise. When I had a Kahr that was slightly defective, they instantly emailed me an overnight shipping label, no questions asked, I shipped it out, and had it back from their shop on which is on the east coast to and from Missouri in less than a week. At any rate, think maybe I'll get some aluminum tape then.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> It is absolutely necessary to tape the seams. A seam will act as a slot antenna, directing the RF energy inside the can. Without the tape, a metal can even with a tight fitting lid will only reduce EMP by about 18 db. Not good enough to protect electronics.


Also, lol, I'm really not being a smart*ss, I'm being serious...if a can with a tight fitting lid with only reduce EMP by about 18 db, will a can inside a can reduce an EMP you think by roughly 36 db? I know nothing about electricity if you haven't guessed by now...lol.


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## sideKahr (Oct 15, 2014)

You don't need the expensive tape. Tests show the cheaper stuff actually works better, probably because the adhesive is thinner.

Yeah, I've had real good customer service with Kahr Arms, too. I love my PM9. It just disappears into a pocket.


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## sideKahr (Oct 15, 2014)

Sir Publius said:


> Also, lol, I'm really not being a smart*ss, I'm being serious...if a can with a tight fitting lid with only reduce EMP by about 18 db, will a can inside a can reduce an EMP you think by roughly 36 db? I know nothing about electricity if you haven't guessed by now...lol.


If you don't tape the seams on either can, you mean? I'd guess only by 18 db, or maybe a little more, but I haven't seen any test data on that configuration. Sorry.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> If you don't tape the seams on either can, you mean? I'd guess only by 18 db, or maybe a little more, but I haven't seen any test data on that configuration. Sorry.


Ya I was gonna edit that to be clearer, correct, I meant if you had a can inside a can, with no tape on either. I'll take your advice though and seal at least one of them if I'm doing cans inside of cans. Better safe than sorry, though if we ever got hit with something strong enough to go through both of them, I think we'll all be pretty sorry some to think of it. Seems like an odd configuration, cans inside cans, but I thought that might offer the same protection as say one can with tape. Better use the tape though I think.


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## Mad Trapper (Feb 12, 2014)

How about a strip of aluminum foil on the rim of the can, to act as a gasket, before you put on the lid?


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## sideKahr (Oct 15, 2014)

@Sir Publius Look at the video I linked. That guy is a NASA engineer, and really knows his shite. His tests use equipment worth tens of thousands of dollars. He'll clear up a lot of questions for you.


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## sideKahr (Oct 15, 2014)

Mad Trapper said:


> How about a strip of aluminum foil on the rim of the can, to act as a gasket, before you put on the lid?


Don't know. They actually make gasketing material for EMP proof seams. It looks like rings of woven steel wool.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> @Sir Publius Look at the video I linked. That guy is a NASA engineer, and really knows his shite. His tests use equipment worth tens of thousands of dollars. He'll clear up a lot of questions for you.


...I don't see a link


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## sideKahr (Oct 15, 2014)

Sir Publius said:


> ...I don't see a link


Up on post #2.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> Up on post #2.


lol...ya...JUST went back and saw that when you posted. Thanks.


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## Mad Trapper (Feb 12, 2014)

sideKahr said:


> Don't know. They actually make gasketing material for EMP proof seams. It looks like rings of woven steel wool.


Maybe after the "gasket" in the rim, add a strip around the seam, after the lid is on, and cover with some duct tape.


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## sideKahr (Oct 15, 2014)

Mad Trapper said:


> Maybe after the "gasket" in the rim, add a strip around the seam, after the lid is on, and cover with some duct tape.


More tape couldn't hurt. Kauboy likes to wrap his electronics three times in aluminum foil, in case one wrap was compromised in some way.

The cookie tin method Sir Publius suggests is light years better than using an old microwave oven, which some people keep insisting will stop EMP. It won't.


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## inceptor (Nov 19, 2012)

Aluminum tape is not very expensive.


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## Sir Publius (Nov 5, 2016)

Mad Trapper said:


> Maybe after the "gasket" in the rim, add a strip around the seam, after the lid is on, and cover with some duct tape.


I would THINK that would work, in lieu of aluminum tape. Seems like it would seal in a similar fashion. Seems to me though that rather than stuffing foil as a gasket, then foil on the outside held on by duct tape, that JUST a strip of aluminum tape would be a little easier probably. But in lieu of having aluminum tape, I would think that would work...though I'm not the expert.


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## Sir Publius (Nov 5, 2016)

Just seems CRAZY to me how little anyone thinks about EMP...the fact that we're not talking just about some sort of nuclear EMP, but that a natural solar one WILL happen again...and when it does, a massive one, it will collapse our society...and no one gives it a second thought. It's just crazy. I wish this were conspiracy theory stuff, but sadly, its really not. I think EMP is one of the greater threats out there. 

I've watched a lot of videos by Dr. Peter Pry on youtube, and he has stated that in NASA's opinion, there is something like a 12% chance of a Carrington class event per decade, meaning, if that is correct, either we will see it, or our kids, and again, its occurence will likely cause utter chaos and anarchy around the world. So taping my little world radip may be a moot point if that happens...but I just can't help myself I suppose.


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## sideKahr (Oct 15, 2014)

@Sir Publius Don't confuse EMP with a geomagnetic storm. Destructive-to-electronics EMP, sometimes called HEMP or NEMP, is produced by a high altitude nuclear explosion, 200-400 miles up. It produces E1, E2, and E3 type RF energy. E1 type is the EMP that kills IC containing equipment.

A Carrington type event is a Coronal Mass Ejection by the sun striking the earth's magnetic field to produce E3 type only EMP. This will not destroy small scale electronics by RF energy; it will only affect electronics that are plugged into the electric grid. The E3 pulse couples to the electric transmission lines and burns out the large transformers in the grid, making it very dangerous.


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## Sir Publius (Nov 5, 2016)

sideKahr said:


> @Sir Publius Don't confuse EMP with a geomagnetic storm. Destructive-to-electronics EMP, sometimes called HEMP or NEMP, is produced by a high altitude nuclear explosion, 200-400 miles up. It produces E1, E2, and E3 type RF energy. E1 type is the EMP that kills IC containing equipment.
> 
> A Carrington type event is a Coronal Mass Ejection by the sun striking the earth's magnetic field to produce E3 type only EMP. This will not destroy small scale electronics by RF energy; it will only affect electronics that are plugged into the electric grid. The E3 pulse couples to the electric transmission lines and burns out the large transformers in the grid, making it very dangerous.


I appreciate the distinction. Never even heard he words "E1, E2" etc. Seems like they do overlap to some extent though, as you say that nuclear EMP causes E3 RF energy, and geomagnetic storms also cause E3 RF energy. It is curious that as many videos as I've seen on the subject that I haven't heard of that at all. I was led to believe that a coronal mass ejections/solar super-storm would in fact, or could in fact fry not just the grid, but non-plugged in electronics as well. Are you saying that's not the case? And if so, where are you getting that info?


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## Targetshooter (Dec 4, 2015)

Great info guys , I have lots of them tins , now I will put them to use .


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## sideKahr (Oct 15, 2014)

Sir Publius said:


> I appreciate the distinction. Never even heard he words "E1, E2" etc. Seems like they do overlap to some extent though, as you say that nuclear EMP causes E3 RF energy, and geomagnetic storms also cause E3 RF energy. It is curious that as many videos as I've seen on the subject that I haven't heard of that at all. I was led to believe that a coronal mass ejections/solar super-storm would in fact, or could in fact fry not just the grid, but non-plugged in electronics as well. Are you saying that's not the case? And if so, where are you getting that info?


An E3 pulse will not affect integrated circuits that are isolated from the grid. Here's a primer I have found quite informative:

Electromagnetic Pulse - Nuclear EMP - futurescience.com


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## Redneck (Oct 6, 2016)

For smaller electronics, I really like using good, rust free ammo cans. I remove that rubber gasket & replace with steel wool. You have to grind the paint off underneath the steel wool gasket & off the lip of the can. Once closed up, test that you have conductivity between the lid & the can. I am certainly no expert but this seems to work real well in that the can is much stronger than any tin plus with the steel wool gasket, you can open & close your container without having to re-tape. Since I didn't line the inside of the ammo can, all electronics placed inside are wrapped or sealed inside a non-conductive material.










For bigger electronics, I use the metal garbage can with a cardboard liner. I built simple plywood shelf to give me upper & lower storage.


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## paraquack (Mar 1, 2013)

I used cookie tins and popcorn tins. All seams MUST be sealed. It must be bare metal 
on any points that need to be sealed. I used lacquer thinner to remove the paint and 
then sanded.
Here's a link to Amazon for the recommended copper foil tape. 
https://www.amazon.com/gp/product/B01EJLT8RG/ref=od_aui_detailpages00?ie=UTF8&psc=1
This copper tape is very thin and can be flattened and compressed very nicely around the seams. 
The adhesive is indeed conductive. I have done the can inside a can method. Some of 
my old "triple aluminum foil wrap" electronics are going into the garbage pail (like above) too. 
Here is a pick of a small can similar to what you were talking about.







Even though I felt the 2 rivets were tight enough, I copper taped them on the inside. This 
particular can has one of my small ham radios sets. It's almost a complete set, only thing 
missing is the battery, so I can charge it twice a year, since the battery won't be affected.
I keep this next to BOB for Grab and GO.


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## Sir Publius (Nov 5, 2016)

I'm a little curious about how items need to be oriented once in your Faraday cage, if anyone knows for sure. Do they simply need to not be touching the cage, so that for example, you could wrap a radio in a couple shirts or a sweater and just lay it in your cage, so its not directly touching the metal, or, is a more rigid insulator between your item and the cage required? Are there certain materials that won't work besides conductive metallic-like material of course?


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## sideKahr (Oct 15, 2014)

Sir Publius said:


> I'm a little curious about how items need to be oriented once in your Faraday cage, if anyone knows for sure. Do they simply need to not be touching the cage, so that for example, you could wrap a radio in a couple shirts or a sweater...


Orientation of the electronics inside doesn't matter. As far as not touching the cage, that's probably a good idea, although a phenomenon called "skin effect" should keep all the charge on the outside of the cage. Wrap the item in any non-conducting material, just to be safe. Newspaper, bubble wrap, cardboard, whatever.


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