So, I take this and a hammer to stamp it into steel? Sounds like hell of work.
Wouldn't I also need lower-case letters?

turn the letter sideways for lower case.

This makes tags for really harsh environments like pipelines, so it should do for permanent code storage including cases like fire and flooding. Not sure if they do lower case but if not just put a slash in front of the char that is going to be lower case.

I'm going to get one and try it out.

http://www.amazon.com/DYMO-Tapewriter-Metal-Embosser-101105/dp/B000FD7Z7I/ref=sr_1_3?ie=UTF8&qid=1413480605&sr=8-3&keywords=tape+embosser

http://www.amazon.com/DYMO-Non-Adhesive-Stainless-Embossing-Cassette/dp/B000O78D94/ref=pd_sim_op_1?ie=UTF8&refRID=0S9RH5Z6WBSQ2RMV22PY