I debated re-opening this thread or responding to the newer thread on same subject - decided it would be shorter to not rehash all for the new thread.
The aluminum tags from Gemplers have arrived.
They are a heavy foil, not solid aluminum. The foil is wrapped around a thin piece of cardboard. This makes them easy to write on (because of the foil it actually embosses when you write) and the cardboard "isolates" both sides so what you write on one side doesn't do a mirror image on the other. The potential down-side is the cardboard interior. I'm a bit worried about what will happen outdoors during a Florida summer. I'm pretty sure water will be able to wick up into the inside, although I have no idea how long it will take, or what effect it will have on the tags integrity. I think it will take care to always write on a VERY smooth surface when using these tags, to prevent the underside from picking up the surface texture underneath.
They are much easier to work with than the stainless washers I have been using. When I tried the numeric stamp for ID number I didn't even need a hammer - just pushing embossed the number clearly (much better than my handwriting). I doubt they will be as indestructible.
The following pics show my original stainless tags:
The Aluminum tag dissected:
The aluminum tag embossed with serial number:
the aluminum tag with printed info: