Steel garbage can as Faraday cage?

[JimRobert]

Looking for simple, practical solutions - what about a galvanized steel garbage can as a Faraday cage (a lot cheaper than a gun safe!), grounded via alligator clip tp speaker wire?

Anyone have any thoughts?

[isopsycho]

There is already a thread on this topic (see thread for additional details), and yes it would make an effective cage as long as you have some insulation inside the can that would separate the contents from the can walls. The weld line on the can will act as an antenna and transmit into the cage, so sanding this down flush with the can wall is a must.

[BumblingBear]

... Interesting.


But you know you're a prepper when:

You keep a scope by itself hanging around just in case you run out of batteries, or an EMP fries the red dot on your AR.

-BB

[james223]

Art. from American Civil Defense Asssoc. use a metal trash can. Put equipment in cardboard box . Place lid on tight , use screen wire if not tight. Place over top several layers if nes.

[bikerdruid]

Originally Posted by james223

Art. from American Civil Defense Asssoc. use a metal trash can. Put equipment in cardboard box . Place lid on tight , use screen wire if not tight. Place over top several layers if nes.

sorry....nes?

[divemedicine]

I have a metal ammo can with my ham radio inside, but I'm not clear on whether or not I can drill a hole in the side for the antenna cable (unplugged while not in use.) It makes sense that I could based on Gauss Law. Ham is isolated with rubber feet and old neoprene wetsuit pieces.

[isopsycho]

Originally Posted by divemedicine

I have a metal ammo can with my ham radio inside, but I'm not clear on whether or not I can drill a hole in the side for the antenna cable (unplugged while not in use.) It makes sense that I could based on Gauss Law. Ham is isolated with rubber feet and old neoprene wetsuit pieces.

For a Faraday cage to work correctly it must be completely sealed (no holes) and the metal can grounded. The EMP will couple with any wire or antenna, on or off, and put a current load on the circuit and toast it.

Unfortunately you can't have any equipment that requires an antenna in an operational mode if your going to have it survive an EMP.

[arisinwind]

Shouldn't the can be grounded? And the welds aren't grounded here.

b. EMP barrier. The EMP barrier is usually a facility-level shield fabricated from welded sheet steel.
The thickness is usually selected for ease of fabrication, but in areas where exceptional mechanical abuse is likely, mechanical strength, as well as workability, may be a consideration. Shield assembly is typically accomplished by continuous welding, brazing, hard soldering, or other fused-metal process to minimize the number of discontinuities in the shield (a weld or other fused-metal pint is considered continuous metal). This shield should be bonded to the earth electrode system in a number of places, typically in a grid configuration with a cable equal in size to the largest earth electrode grounding conductor. This bond should be a continuous weld to preclude any potential high resistance bonds that may develop with aging of the facility.

[The Saint]

OK does anyone else on here have a "faraday room" ?

[isopsycho]

Originally Posted by arisinwind

Shouldn't the can be grounded? And the welds aren't grounded here.

b. EMP barrier. The EMP barrier is usually a facility-level shield fabricated from welded sheet steel.
The thickness is usually selected for ease of fabrication, but in areas where exceptional mechanical abuse is likely, mechanical strength, as well as workability, may be a consideration. Shield assembly is typically accomplished by continuous welding, brazing, hard soldering, or other fused-metal process to minimize the number of discontinuities in the shield (a weld or other fused-metal pint is considered continuous metal). This shield should be bonded to the earth electrode system in a number of places, typically in a grid configuration with a cable equal in size to the largest earth electrode grounding conductor. This bond should be a continuous weld to preclude any potential high resistance bonds that may develop with aging of the facility.

US STRATCOM deals with this everyday, although they typically disregard some aspects because it gets expensive or it difficult to maintain. Maybe its just in the wording...?

Anyway, grounding the can is paramount otherwise the EMP will transmit again inside your metal can. The complicated narrative above simplified means the earth ground should be highly alkaline (conductive and dissipative) and that the path to this ground needs to be continuous (aka low resistance as possible) and the more the better (more paths to ground that is).

Unfortunately, high alkaline content means a high corrosive factor to conducting materials (US STRATCOM's concerns on upkeep).

[isopsycho]

Originally Posted by The Saint

OK does anyone else on here have a "faraday room" ?

Very expensive to build unless you have an underground room with at least a couple of feet of earth for a barrier. The earth barrier will pretty much attenuate the high frequency portions of the EMP leaving you with just the low parts. A simple metal sheet or even metal mesh will direct the low frequency pulse to ground.

I use three Pelican cases with metal liners. The foam inserts insulate the objects inside. The corners are rounded with no weld spots to reduce the antenna effect with the cover/lid making a metal to metal contact using a wedge lip. The cases have grounding points at three corners each, all linked into my basement grounding pole.

When I finish my BOL it will have an equivalent storm cellar underground where my Faraday cages will go. I operate under the repair part replacement concept since you won't know exactly what gets fried if it does at all (mainly do to the many variables involved in the coupling effect of the EMP).

[NeuroByte]

Originally Posted by The Saint

OK does anyone else on here have a "faraday room" ?

I'm thinking of using a shipping container just for this reason, worn out shipping containers are relativity cheap because it's more expensive to repair and re-certify than to make a new one.

[isopsycho]

Originally Posted by NeuroByte

I'm thinking of using a shipping container just for this reason, worn out shipping containers are relativity cheap because it's more expensive to repair and re-certify than to make a new one.

Where you getting your shipping containers? These the SeaLand containers from container ships?

[NeuroByte]

Originally Posted by isopsycho

Where you getting your shipping containers? These the SeaLand containers from container ships?

haven't bought it yet, but yes a standard intermodal shipping container.

http://en.wikipedia.org/wiki/Intermodal_container

it solves a lot of problems, pre-built, easily transported, strong, etc etc. I'm not the first person to think of this, check out this guy
http://thefieldlab.blogspot.com/

The shelter i'm designing is roomy enough for a decon shower.

[isopsycho]

Originally Posted by NeuroByte

haven't bought it yet, but yes a standard intermodal shipping container.

http://en.wikipedia.org/wiki/Intermodal_container

it solves a lot of problems, pre-built, easily transported, strong, etc etc. I'm not the first person to think of this, check out this guy
http://thefieldlab.blogspot.com/

The shelter i'm designing is roomy enough for a decon shower.

Awesome! You find a retailer or seller for the containers?

[Halkon]

can you ground a car to the Earth, or does it have too many seams?

[isopsycho]

Originally Posted by Halkon

can you ground a car to the Earth, or does it have too many seams?

In theory you should be able to, however, given the number of seams, bends and open pathways for a reflected pulse to propagate there still lies a good chance some form of coupling will take place.

There is really no way to test (short of asking PAX river Naval Air Station use of their EMP test platform). Given the amount of wiring in the car, plastic light covers would allow quite abit of coupling directly to the internal wiring system.

If you could completely isolate the ignition and timing circuits (to include the computers) from the rest of the vehicle (mainly the main fuse/power box) then maybe you could shield the critical components and drop a few grounding straps. Of course this won't work while driving since the grounding needs to be very stable.

[NeuroByte]

Originally Posted by isopsycho

Awesome! You find a retailer or seller for the containers?

Haven't looked for one yet, still in the design phase, but shouldn't be too hard. You see at most ports they usually have a surplus of old containers, and they tend to sell them for storage, (My local walmart has one behind it filled with grills in the winter).

but honestly, ebay, it sounds stupid but they have 'em for $1000-$3000 depending on size and features.

[isopsycho]

Originally Posted by NeuroByte

Haven't looked for one yet, still in the design phase, but shouldn't be too hard. You see at most ports they usually have a surplus of old containers, and they tend to sell them for storage, (My local walmart has one behind it filled with grills in the winter).

but honestly, ebay, it sounds stupid but they have 'em for $1000-$3000 depending on size and features.

I just checked eBay, your right: around $1-5K depending what size you want. Sometime, when I get an actual homestead, I'll set one up as my EMP proof underground parking bay and tool shop

[name]

microwave.