Blockplate can be purchased at blockplate.com. It claims “Exceptional strength. Fire and heat protection (Up to 1149°C / 2100°F). Water and corrosion resistant. 12 Gauge 304 Stainless Steel is tough against wear and tear.” The unique thing about this design is that it uses neither stamping nor etching. A simple center punch stores your seed in minutes with a dot for each character.
Setup
This was the first time I’ve used a center punch style metal storage device and I have to say it was the fastest and simplest to set up. Hammering a center punch is much simpler than trying to hammer a metal letter stamp. It’s also less jarring than trying to use a dremel to etch letters.
Heat Stress Test
Performed admirably — dots were easy to read, no data loss.
Corrosion Stress Test
No data loss.
Crush Stress Test
No data loss.