Is a cake dummy something special? Or can I just cut some styrofoam and use that?
You could just cut styrofoam. However, that is a royal PITA. Little styrofoam floaties that fly everywhere and stick to everything. Plus the edges aren't always really smooth. And the cake dummies are pre cut with smooth edges and sides, in all the common cake sizes, and pretty cheap.
The alternative is a hot wire cutter, which I have found for $100....cheaper to buy the dummies. At least for me.
thanks so much I think I"m just going to bite the bullet and buy some.