Just for sport, I made a die the other night from 6061t6511
The deepest details in the cavity were .06"
The sheet sample I used was 5052? .020"
I tried a .5" panel of urethane, maybe around 60-70 durometer, sort of
worked,
but the process destroyed the urethane.
I tried again with .19" thick urethane, maybe 85 durometer, and got much
better results.

I was curious who has played with this, if you can recommend interesting
relative websites, and any suggestions on guidelines for this process.