I will be making a cake for my friend's "Golden Birthday" this weekend and I intend to use white fondant to create some type of retro theme. I plan to paint the fondant pieces with a gold luster dust mix (luster dust + lemon oil or vanilla). How far in advance can I cut my pieces out and paint them? How long do I have to wait after painting the pieces before I can add them to the cake. I have never anything like this before, so does anyone know if it will give me the gold shine that I am looking for? If you have any additional hints or tips that may help me, please pass them along.
One other question. I know moisture can breakdown royal icing, but if I wanted to may some numbers out of royal icing and paint them with the gold luster dust, would I paint that on dry or use the mix I noted above for the fondant?
If you're trying to get a shiny gold color, you'll be better off starting with dark ivory or tan or yellow fondant, depending on the shade of gold you want. Especially if the dust you're planning to use is the Wilton one I've used it and it won't give a gold color with white fondant. Paint with lemon extract rather than lemon oil, or paint with vodka...it's cheaper and they work about the same. I keep the vodka in a dropper and just add more as the mixture dries out.
When you're putting pieces on the cake, if you want them to follow the contours of the cake, then cut them out right when you want to put them on the cake. If you cut them out sooner, they'll dry hard and stick out from the cake. It's not hard to paint pieces that are already on the cake...if you can paint your nails, then you have the skills to paint your fondant.
Ditto on coloring your fondant yellow (or gold - I use Americolor gold gel) before painting with gold luster dust.
Ditto on mixing your luster dust with vodka or other clear alcohol (I use Everclear).
Ditto on painting the pieces after they're on the cake. It's easier than you think. Once the alcohol evaporates, the luster dust will come off on your hands, if touched, so the less handling, the better.
As for royal icing, you can paint it with the luster dust+alcohol mixture. The alcohol evaporates so fast, it doesn't have a chance to weaken the royal.