I've done it 3 times. The first couple of times, it seemed to flake off or wear off rather quickly. I may have not prepped the surface well enough.
The last time I used it, I actually baked it in a gun oven for 4 hours to cure it. This method yielded the best result for me. The finish was 5 layers and it's ROCK hard, yet flexible.
I'm going to try to do it again on a couple of slides. This time I will double-prep it and try it without the oven (as it was intended).