Hi everyone!

I have to make a tiered cake for a 40th birthday party and for the "topper" I want to do poured sugar into the number 40. I want to do it as a mold instead of just winging it when I pour it so that it doesn't all run together as it is poured. Does anyone have any suggestions on what I can use for a mold? It is going to be going on top of a 6" round cake (6" top 8" middle 10" or 12" bottom). Thanks in advance

Holly