I am making a castle cake for this weekend. I didn't have any fondant to use on the columns & since it isn't going to be eaten anyway I used gumpaste. I made them last night and set them to dry. I went to go apply the luster dust with a little lemon juice and it looks awful. I also tried applying the dust with a dry brush and it looked dull.
What am I doing wrong? Is there anyway to get some color or accent on them.
When I make gumpaste flowers, I dust the petals with a dry bush and then steam them with a tea kettle ever so slightly. It sets the colors and usually makes them shiny... I've never tried it on for your application though.
I use dusts with gumpaste all the time. However, you said you used lemon JUICE? Not lemon extract? That could be part of your problem. The purpose of using extract (or alcohol) is that the liquid evaporates rapidly. Vodka works the same. I mix up a little bit of dust in a pinchbowl with a few drops of Everclear, just enough to make it liquid, and paint it on. The more alcohol you use, the thinner the coat will turn out. Even so, it works best if you apply one thin coat, and then after it dries add a second and often even a third coat. Check out the gumpaste Elvises I just uploaded, they were painted with super pearl dust and also silver/gold luster dust using the method I just described.
You can use clear extract and clear alcohol, like ceshell mentioned above.
I use confectioner's glaze all the time. You have paint to one coat and let it dry. Then apply the second one. Till you get the colour you desire.