Topic: Testing Plat SS304 to Convince Myself (Read 182 times)

He is a great guy and we can all learn a lot of him, including how to protect and backup bitcoin keys in a good way.
I remember some time ago one guy created his own metal backup product and his first post was in bitcointalk forum, than I suggested him to send it to Jameson for testing/rating and he accepted it.

Yes, Jameson Lopp is my role model my purpose to testing plat, I once wrote his tests here - (my local board) - For me, it is certainly difficult to follow precision in what he did because my equipment is incomplete like he has.

Lot of batteries in vehicles have sulfuric or other acid stored in them, and in theory there could always be some acid rains or chemical spill disasters, so it's better to be prepared for those scenarios.
I suggest checking out how Jameson Lopp conducted his testing experiments, this can be fun.
You can find his comparison list with rating for Overall Grade, Heat Grade, Corrosion Grade and Crush Grade:
https://jlopp.github.io/metal-bitcoin-storage-reviews/

for multi-layered security, it is good to store it in a metal safe box. but based on my test above, storing it in a regular cabinet is safe.

It's always smart to test things that most people take for granted - because a few years ago Jameson Lopp tested a lot of metal seed storage and some of those products proved to be completely unreliable when it comes to fire or failed the hardness test.

It may not make much sense, but such plates can be additionally protected by storing them in metal boxes and fireproof boxes/bags. If nothing else, at least it will be easier to locate them if we have such an accident that our house or apartment burns down.

For real life, we don't often hear about calamities caused by Acid Liquid. I made this based on a fire that happened on LA. And, of course for those people on LA who store their seeds in SS304 plates will be safe.

however, if I have free time, I will try it using sulphuric acid (H2SO4).

Great testing Chikito and very practical real life use of famous saying Don't Trust, Verify
Another test you can do is with using Acid liquid, I remember Jameson Lopp was doing something similar when he tested a bunch of metal backups.
I was also thinking of doing something similar with stainless steel washers, they are very cheap and I can't be sure if they are poorly made in China on not.
This days you can't be totally sure if you are buying the real thing or some cheap metal alloy.

yes, punching the stamping tool letter deeper is good if we have a plan to do heat treatment. but it must be precise, because if you do it twice, often goes off the rails.

I also made 3 materials ( 3 plat of 4 word seeds = 12 mnemonic seed) with the same size by marking the number on each plate (1,2,3) so as not to be confused which word seed goes first.



but it all depends on the taste, we can make it into 1 big size plate, it's cheap costs less than $2

One thing I have noticed is that the heating and cooling process made some of the letters darker. It is not a big deal for seed phrases, but it would be much better if you could do a uniform press. Not only would burnt parts disappear, you would also be able to make the letters more uniform and in a straight line.

I'm pretty sure with a larger sheet you can accommodate 12 or even 24 words, but you'd have to shrink the text size a little.

yes I did on Rockwell hardness test and use Linear Regression method to take conclusion if the treatment makes steel more than harder before being burned and doused with water.



I got an increased HRB result as graphic below.

Generally speaking the mechanical properties of Austenite Steels like 304 like hardness (204 is pretty close as well) because of their chemical composition should not change noticeably with heat treatment, specially with the temperature range and time you used here which is performing what is close to Annealing.

The hardness of AISI 304 can mainly be changed through mechanical work like rolling, cold drawing, etc.

The reason why this type of heat treatment followed by quenching (ie. rapid cooling of the heated metal) is increasing hardness of certain carbon steels is their carbon content which needs to be higher than what AISI 304 has so that it can form crystalline structures such as Martensite. Like what we have in case of AISI 420 with 0.2% carbon.

The only way to be sure if your plate actually got harder is to perform hardness test.
Keep in mind that other variables throughout this process can affect the mechanical properties of the plate. Like adding carbon to the steel during heating in the furnace (aka carburizing) which could indeed increase hardness of AISI 304. Of it the metal was heated to a much higher degree (melting point) before being cooled, the hardness can also increase due to different crystalline structures forming like dendrites (this is what happens in welding).

Besides I testing it to convince myself, what I'm doing above can also be used as for heat treatment. That SS204 steel become harder after the treatment.

maybe it should be good if stamping first the 12/24 word mnemonic seed in that plat before performing heat treatment because it's hard when do it after.
 

AISI 304 is a low carbon steel so its melting temperature is high above 1400 °C



What you did here (the vertical red line) is basically some sort of heat treatment. I believe all this achieved was some level of "stress relief" for the steel plate (IIRC 304 needs to be heated to 1100 and for a longer period for a proper process).
To put simply you slightly affected the mechanical properties of it. I don't believe the structure could have changed, it should still be widely austenite with nary a martensite structure in it. And that with the assumption that your water was cool (20-30 degrees), if it were warmer (like 60) that wouldn't have been quenching. Although you could perform metallography on it to see that.

In any case, 900°C for 10 minutes (or any longer period) is not enough to damage this type of steel for our purpose which is offline key storage.

A year ago, I purchased plat steel SS304 to make sure my 12/24-word mnemonic seeds were safe.

and I thing if I buying a pre-made one is enough expensive, I decided to make my own storage by purchasing a plat SS304 online. It was cheap, costing less than 100,000 IDR, So  I could cut it into several pieces, leaving plenty of leftovers for storing other things.

And coincidentally, I currently have job on workshop, and there’s equipment available for metal tempering.
So, I took the initiative to test the SS304 I bought. I want to make sure, as there’s a possibility that the SS304 sheet I purchased might not be genuine.
So If something were to happen, like a fire, I wanted to know if it would melt or withstand the heat.

1. I cut a small piece of the sheet (as a specimen), measuring 65mm in length, 33mm in width, and 3mm in thickness. Then, I stamped it.



2. I prepared to heat it in a furnace using a Nabertherm-branded machine from Germany. Once the temperature reached 900°C, I placed the sheet inside and waited for 10 minutes.



3. After that, I took it out, and with the help of a friend, I quenched it in water (though it might have been better to let it cool naturally without water).



4. The image below shows the appearance after heating and tempering. There were no significant changes, and the stamped text was still readable, though it had darkened slightly.



5. To remove the darkening, I decided to sand it down, and the text became clearly visible again.



Conclusion: The SS304 sheet I bought online is indeed genuine and can stand with temperatures of 900°C for 10 minutes. In some cases, 900°C is the highest temperature reached in a house fire, and 10 minutes is the fastest response time for firefighters to arrive and extinguish the flames with water.

This can serve as a reference to storing your mnemonic seed words on SS304.

a. My reasoning for choosing 900°C is based on [1].

[1]. https://www.cnnindonesia.com/nasional/20201023194626-12-562173/suhu-api-kebakaran-kejagung-capai-900-derajat-celsius

b. The actual response time for firefighters is 15 minutes [2]. However, since this is a critical matter for me, I can assure you that if such an event were to occur, I would prioritize saving the SS304 sheet from the safe. So, 10 minutes is the maximum; it could be less since I’m confident in the layered safety.

[2]. https://sippn.menpan.go.id/pelayanan-publik/sulawesi-selatan/kabupaten-soppeng/layanan-response-time-penanggulangan-kejadian-kebakaran-

c. If you’re unsure (e.g., when buying online) whether the plat is genuine SS304, titanium, etc., it’s best to test its composition in a lab.
However, that’s expensive and not cost-effective compared to buying certified genuine products. I conducted the manual test above because I had the opportunity. If you’re in a pinch and unsure, you could try testing it on a gas stove, but make sure to ask for permission from your family first.

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Original thread: https://bitcointalksearch.org/topic/m.61633488