Quote from: m2017 on April 05, 2022, 06:12:06 PM

With this mini-experiment, I want to clearly show that 4 words can be applied to 1 washer. 2 on one side and 2 on the back. If reduce the number of letters to 4 (this is enough to identify the desired right word and restore seed-phrase). There is still space for numbering the puck so as not to make a mistake with the word order.

It's not like you are going to drastically reduce size by doing this experiment, and you are increasing chances of mixing up correct ordering of words that could lead to losing of your funds.
Stainless steel washers are dirt cheap, you can buy them anywhere in your local areas, so reducing cost is not appealing enough for me to do this.

Quote from: n0nce on April 05, 2022, 07:03:43 PM

Keep in mind that these backups are supposed to withstand extreme conditions, under which a letter may become indecipherable. In such a situation, you'll be happy that you wrote down more than the minimum required 4 letters per word.

When you are talking about extreme weather conditions, I don't know if you know this but 304 stainless steel can easily be corrupted if exposed to salt water, so if you are living in are near sea water I would opt out for better 316 stainless steel.
I am not sure if Jameson Lopp did any tests with salt water, but I believe that is much more realistic threat for some parts of the world compared to acid exposure.

Not all stainless steel is made the same, there are different types and grades, so while 316 SS is better for salt water it does have a bit lower melting point compared to 304 SS:

Grade 304 melting points: 1400-1450°C (2552-2642°F)
Grade 316 melting points: 1375-1400°C (2507-2552°F)
Grade 430 melting points: 1425-1510°C (2597-2750°F)
Grade 434 melting points: 1426-1510°C (2600-2750°F)
Grade 410 melting points: 1480-1530°C (2696-2786°F)
Grade 420 melting points: 1450-1510°C (2642-2750°F)