I have been trying to use the luster dust to paint a small tiara on one of my fondant/gumpaste figures. When I mix it with the vodka it just becomes either WAY too diluted, or becomes a clumpy sticky mess that I can't paint on at all. What am I doing wrong? It doesn't seem like it should be this hard.

This is a very common problem. There are a couple of options that might help a little. One is to use an eye dropper to add more alcohol as needed. This keeps the consistency a little more stable. The other option is to use almond or lemon extract instead of vodka. The oil in the extract makes smoother paint a little more working time. The paint takes a little longer to dry, but this can work for you if you work in "layers".

HTH

Michele