Improvised Faraday Cage...?

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Son Of Andrew
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Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 4:32 am

Hi Folks,

I've searched on this site for references to the above and found very little, but please excuse me if this topic has been raised elsewhere and I missed it...
Sorry, total tech-noob here... Does anyone have any experience of building a Faraday cage, and could they please tell me, would a sealed Mylar bag constitute a Faraday cage in and of itself? I was bucketing beans the other day and the thought occurred to me that I could possibly use them for the purpose.

If so, it's surely a simple matter of bucketing your electrical items just like your food. I think the bag itself is a Faraday cage, and the bucket would simply protect the bag. It'd be a simple and economical fix if it works. Am I right in thinking that if it blocks the signal from my mobile then it'll do the job? If I seal the mobile in the bag and it doesn't ring when called, surely it'll work to save items from an EMP...

If someone could let me know, please, I'd really appreciate it.

Cheers, ta
Matthew.
=0)

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 5:45 am

I should clarify... I've found a LOT of references to Faraday cages on these boards, but no actual builds or 'concrete' resources, or references to Mylar bags as such. Many of the threads are very old and links to external resources defunct. If anyone would care to help me, I'd really appreciate it, thank you.

M.
=0)

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korolev
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Re: Improvised Faraday Cage...?

Post by korolev » Wed Jun 17, 2020 8:57 am

Get a 1 metre length of copper pipe or similar. Hammer it two thirds into the ground. Run a nice thick cable from it to a metal tin (biscuit tins are good, not least because you have to eat the biscuits) . To ensure it is properly connected rub sand the paint off a small area, drill a hole and affix the cable using a nut/bolt/washers.
If the weather is dry for a long time, water the earth spike.

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 9:48 am

korolev wrote:
Wed Jun 17, 2020 8:57 am
Get a 1 metre length of copper pipe or similar. Hammer it two thirds into the ground. Run a nice thick cable from it to a metal tin (biscuit tins are good, not least because you have to eat the biscuits) . To ensure it is properly connected rub sand the paint off a small area, drill a hole and affix the cable using a nut/bolt/washers.
If the weather is dry for a long time, water the earth spike.
Thanks for your response, Korolev. So it's the earth that's the important thing. You've tried one of these yourself, I presume. Do I need to line the tin with anything? =0)
Cheers,
M.

GillyBee
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Re: Improvised Faraday Cage...?

Post by GillyBee » Wed Jun 17, 2020 11:45 am

Korolev's solution will work nicely. Earthed metal all around.

Most computer spares -hard drives etc arrive in antistatic bags which are basically mylar so clearly there is something in the idea. The problem with mylar is that you don't know for sure that it is antistatic. You would need to test. And even if antistatic, the level of protection is likely to be minimal.

If you are really worried and have a lot to store, use a shipping container. My first job with an electronics firm involved spending all day running measurements inside the departmental Faraday cage. It was an 8ft shipping container in the middle of the workshop floor with the door firmly shut while testing.

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 4:46 pm

So it's not as easy as I thought, and it's the static discharge and the earth which are important. Awesome. I really appreciate you taking the time to enlighten me. I had trouble with the premise before, but now I understand. My thanks to you both.

M.
=0)

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 8:25 pm

I'm not going to pretend I went to any effort here on my part, these sites literally came up in the first few hits on Duck Duck Go, but they seem pertinent. I'm reading them now, I just thought I'd post it here to continue the discussion, and as a point of reference. I hope that's ok.

https://www.askaprepper.com/10-faraday- ... e-at-home/

https://www.wikihow.com/Make-a-Faraday-Cage

What do folks think? Is it really as easy as wrapping a cardboard box in tinfoil? I'm not so sure... =0\

I also know of someone who tried the galvanised rubbish bin method and he said it failed miserably.

Apparently the sure fire way to know, according to the comments on this page, is not a mobile phone test like the one I mentioned, but an AM radio test. This would tell you for sure if your improvised cage will work.

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Wed Jun 17, 2020 8:34 pm

I think this might be viable... If I seal the items individually in Mylar bags, then inside a metal bin instead of plastic, then attach the earth and spike as per Korolev's advice. That's gotta cover the bases, I reckon.

Raven
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Re: Improvised Faraday Cage...?

Post by Raven » Thu Jun 18, 2020 5:52 am

Son Of Andrew wrote:
Wed Jun 17, 2020 8:25 pm
What do folks think? Is it really as easy as wrapping a cardboard box in tinfoil? I'm not so sure... =0\

Apparently the sure fire way to know, according to the comments on this page, is not a mobile phone test like the one I mentioned, but an AM radio test. This would tell you for sure if your improvised cage will work.
I made one wrapping a cardboard box in tin foil making sure the tin foil connected all the way round, and the mobile signal still went through so I either did it wrong or it doesn't work.

I wanted to try a locker box next and insulate it out.
Keep calm & carry on PREPPING :twisted:

Son Of Andrew
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Re: Improvised Faraday Cage...?

Post by Son Of Andrew » Thu Jun 18, 2020 5:56 am

Raven wrote:
Thu Jun 18, 2020 5:52 am
Son Of Andrew wrote:
Wed Jun 17, 2020 8:25 pm
What do folks think? Is it really as easy as wrapping a cardboard box in tinfoil? I'm not so sure... =0\

Apparently the sure fire way to know, according to the comments on this page, is not a mobile phone test like the one I mentioned, but an AM radio test. This would tell you for sure if your improvised cage will work.
I made one wrapping a cardboard box in tin foil making sure the tin foil connected all the way round, and the mobile signal still went through so I either did it wrong or it doesn't work.

I wanted to try a locker box next and insulate it out.
Yeah, I didn't think so, somehow.. I always appreciate hearing from those who've tried things out personally, even if they failed. Awesome, thanks for your input, Raven. =0)

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