I made a styrofoam dummy to use to drape fondant/gumpaste over so that it will dry and then I can gently remove it and place it on the cake. Do I dust the dummy liberally with corn starch or powdered sugar? What can I use to coat the dummy to fill in the holes in the styrofoam and then be able to lift off the fondant shape without it breaking?

Thanks for all the help!

You could cover the styrofoam with foil or wax paper, and make sure your underside of fondant/gumpaste is liberally powdered with cornstarch or powdered sugar. My question is why are you wanting to do it in this method? It seems like you're more likely to end up with rips and broken pieces trying to move it. Sounds like extra work to me so I'm curious the purpose. Good luck!

I'm curious too. Sounds like extra work, and how will you know with certainty that the fondant shell will fit on the actual cake?

Hope this helps, I cover my styrofoam with saran wrap-tape it down and liberally dust saran wrap with cornstarch before I add my fondant or gumpaste I want to shape. I am able to remove it easily when it dries.

Thanks for all the replies. Due to bad thunderstorms last night, I couldn't get back online to read the responses.

I am making a baby shower cake and the client wants a cake she saw here on CC - it's a bassinet, complete with a top. The CCer that made the cake used cardboard strips to make a form to shape the bassinet top. I tried that, but wasn't happy with my results, so I shaped styrofoam to fit the size of the cake. I can spread the fondant/gumpaste mix over the form, let it dry and then lift it off to put on the cake. The bonus is that I will have the dummy form to use for future orders The most time consuming part was carving the styrofoam, but it was good carving practice for me and once the mess was all cleaned up, the worst is over and now I can have fun