ColdTI can be purchased at coldti.com. It claims to be fireproof, waterproof, timeproof, tamper resistant, very high melting point, extreme durability.
I felt like the space was cramped. I know you only need the first 4 letters of a word but I feel safer if you can write the whole word. Also, reading the etched letters is somewhat difficult because there is no contrast against the background. Stamping seems to be the way to go here.
Heat Stress Test
The screw to which I was applying the flame actually melted and could no longer be turned. I opened it via the other screw to discover that the engraved words were completely lost at the point of heat application. Stamped words were still visible. So that’s a catastrophic failure for engraved seeds on the ColdTi. More reason to only use stamping with this product.
Corrosion Stress Test
Once the bubbling calmed down and the acid became clear again it was obvious what had corroded — the screws holding the ColdTi together had completely dissolved! However, there was no additional data loss after the heat test.
Crush Stress Test
Deformed but did not result in additional data loss.