Does anyone have a Faraday bag for phone that works?

i made one with tinfoil and a ziploc bag

Did it work?
- yes took about 6 layers of tinfoil though

I do!

My use of a Faraday bag is more prepper oriented (i.e. solar flares) instead of geared towards privacy, but I keep a Pixel 8 with GrapheneOS, linux laptop, and eReader in a SLNT Faraday bag.

My tests have been far from perfect, but the phone's Bluetooth and cell reception have all ceased working once put in the bag.

Aluminum foil works. At least, I can't receive calls or texts through it last I tried.

Get the heavy duty kind. It's not any more conductive, but is more durable against tearing.

Note that a gap in your phone's tracking data can look suspicious at times. Sometimes it's less suspicious to leave your phone at home.

I second this. I've seen videos of cell phone thieves getting caught and they all have rolls of aluminum foil on them. I trust they know how to effectively block wireless signals.
- Getting caught? Can’t work that well then!
  jk
Just want to note here that suspicion does not equal proof. Consider honestly what you are trying to accomplish, and what the risks are. There are absolutely scenarios in which even raising suspicion is unacceptable, and others where it isn't.
- I'm not selling dope, I just don't need Google knowing everywhere I went on the way to the doctor's office, where I'll probably sit and look at cat videos in the waiting room. I have anxiety and I can't stand surveillance like this constantly.
It’s not any more conductive
quick note: you're likely correct the conductivity may not be higher, but the conductance likely is.
in other words, i second your suggestion of heavier duty foil (for EM reasons, skin effect etc) alongside the mechanical factors you mentioned.

Bags don’t really work, but hard shell boxes do.

Back when I was working with radio devices, we needed real isolation on lab benches, along with the ability to selectively allow RF paths with specific impedance. The gold standard was Ramsey test equipment enclosures, and they really work (although they only provide isolation up to about 90 dB at the frequencies we cared about; for extreme isolation sometimes we had to nest two like Matryoshka dolls).

It doesn’t sound like you need any conducted signal, just isolation, so that will make for a cheaper bulkhead. Here’s the smallest/cheapest Ramsey enclosure. You can probably find used ones on ebay for less, but you may need to hunt for a while.

Another company that makes real enclosures is ETS Lindgren but they’re larger and much more expensive.

If you don’t like the weight/bulk/cost of that solution, then no, you’re not going to find something that actually works.

That certainly is cost prohibitive. Is it because of the frequency range of cell and wifi?
Also, thanks. I still might get one.
- I have a little more time now to write more. A Faraday cage needs to fully enclose an object with electrical conductivity in all directions. Solid metal is best, but holes are fine as long as they are substantially smaller than the RF wavelength you’re trying to block.
  WiFi has wavelengths between 5 and 13 cm (speed of light divided by frequency). Microwave ovens are also around 12 cm and you can see the small holes in the screen you can see in the glass through the door. “Substantially smaller” than 12 cm, at least by an order of magnitude (10x), but approaching 2 orders (100x), around 1 mm.
  5G is a bit all over the place, so let’s stick with wifi.
  What matters is the size of the holes in your mesh, the type and thickness of metal, and the quality of the electrical contact across all seams. No gaps bigger than a half millimeter (based on 1/10th the wavelength, or maybe no gaps under 0.05 mm), anywhere. Bags have sewn seams and could spend a little or a lot of effort making it be conductive. Conductivity isn’t a normal sewing consideration and doing it well costs more. Then there’s the access hatch.
  In an Anechoic chamber, the door has very good copper (and possibly gold plated, I don’t recall) connections all around a solid door on a big hinge with a big handle that cam-locks everything tightly. Obviously that’s really expensive, but it scales down from there. A good mesh bag folds the lip over on itself, but its still going to be poorly electrically connected at a micro level, especially with dirty durable metals.
  You’ll open and close it a lot and it will definitely flex and get dirty, so I expect it to get worse over time.
  The seam on a Ramsey box is a U-shaped aluminum channel on the bottom, containing conductive foam covered in a flexible wire mesh layer that gets compressed against the top aluminum edge in the middle. All of the aluminum edges are raw for electrical connectivity, while the outer shell of the aluminum box is coated to make it durable and easy to handle. There’s a decent latch to put a lot of force into holding it closed and compressing that foam tightly. It wears out over time. There’s a lot of work that goes into making that $600 box perform really well.
  I’m sure you could find a bag that works half decently, but it will be pretty expensive and it will get worse over time. I’ve handled an evidence bag designed to keep devices isolated in transit. It looked decent, but I didn’t test it. Maybe you can find one of those but I bet it’s not from Bezos.
  I kinda disagree with your overall plan being the best response to pervasive corporate and government surveillance, but you should at least be empowered with a scientific basis to evaluate a solution so I hope that helps.
  Science Fucking Matters.
- I think it’s mostly about durability and great conductivity all along the closure.

Using a few anti-static bags inside one another doesn't block 100% of signals but it cuts range down by a lot. But also, if you're looking for this high of a security level, wouldn't it be easier to just find a phone with a removable battery?

LOL Have you tried to find a phone with a removable battery lately?

First off, there's 200 more practical things you can do first. A Faraday bag isn't going to accomplish more long term then your phone simply being stripped of bloat and tracking apps, or simply being turned off.

That being said, if you must, Mission Darkness bags are decent, and I've tested them and they do block WiFi, BT, and cellular signals.

YMMV, and understand that when you phone is in the bag, it might as well be turned off. You can't access it without opening the bag.

I also vouch for mission darkness. Well made. I have a work iPhone that I keep in blackout when I am off. No signals have gotten through and the apple tracking feature is also null.

I don't think I am the target audience for these products, and have no answers for you, but am curious what these would do above what turning the device off. Is a device that is powered off still reachable? Or is this not about that?

Anyway, on to the non answers, when i worked around wiring that needed to not be affected by interference from adjacent wiring, it would we shielded by aluminum. It was thicker than household foil, and had braiding. The wires could be run with other, non shielded wires, most of which were dramatically different voltages.

I am not a scientist 😅

Lots of devices still communicate when “powered off”.

Why would one want to put their phone in a faraday cage? I know what the cage does, but don't understand why you'd want to use one instead of turning the device off.

Edit: According to this, unless your phone is compromised, turning it off is sufficient.

PDF link: https://media.defense.gov/2020/Aug/04/2002469874/-1/-1/0/CSI_LIMITING_LOCATION_DATA_EXPOSURE_FINAL.PDF

Some phones, even if they are turned off, still send telemetry data.
I use GrapheneOS and for safety reasons, when I know I won't get a call, or if I have to travel somewhere discreet, I'll use one :P Works well for me!
- Some phones, even if they are turned off, still send telemetry data.
  I can't find anything other than redditors making this claim. Is there a better source I can look into?

Are you trying to EMP-proof your phone, or block signals/tracking for a time?

I just want it to not be tracked constantly.
- Only while you're using it?

I have a bag from silent pocket. Works great.

SLNT Faraday stuff is supposed to be good. I've never used one. Michael Bazzell recommends them.

They work good, phone lost all connectivity inside. So does Mission Darkness.

Something meant to maintain a high or low temperature. A Thermos or pizza delivery bag or a bag for bringing frozen groceries home. Some might just be foam, but there are also ones with metalic coating or a steel shell.

From what I heard you won't find a real Faraday bag that works well and blocks almost all signals, those found on Amazon are really not that effective and only "military grade" bags could be useful in these kind of threats

Okay. That means I need to chexk the surplus stores. Maybe I will get lucky.
- I don't think that if real Faraday bags meant for military work they are avaible in surplus store for civilians
You can always test, try calling your phone in different bags
- When talking about real and useful bags I'm talking about those that are blocking almost all the frequencies. Putting a device in a Faraday bag means that it's not safe at first so it should be able to block all frequencies not only "call frequencies"