Always let it dry and harden, it will resemble matte porcelain. Only when every piece has been sanded then I airbrush (of course not every piece will need to be sanded, it depends how the surface looks and feels). Because its so fragile I always make extra pieces. Sometimes they will crack for no reason.....
When assembling, make sure the glue is not super hot, otherwise that could cause the pastillage to crack, if not right away then maybe later on. (thermal shock)
Remember: they can snap off or crack just by being handled and set on table, or by vibrations on a table. I always place my pieces on soft foam.
ps. Dry it slowly to prevent the sides from curling. Try to make sure its perfectly smooth before painting.
Before painting it, should be glazed in the oven with a coating of gelatine dissolved in water, this will prevent bleeding if you are using water colors. If you are using artist's paint , then there is no need. I have seen many work their pieces without the coating especially when using pastel colors, darker colors for the highlighting, darkest at the end.
Some work on a wooden board to prevent it from drying quicker, I have never .
Edited by petalsandcoco - 2/23/12 at 6:08am