I want to stencil my daughter's wedding cake, which is buttercream, with royal icing. Will this work, or will the buttercream break down the royal icing? I want to use royal icing because I need to lustre dust the stencil. What about color flow on buttercream?

I use buttercream on buttercream when stenciling.. I just make sure my buttercream is crusted well before I do it. I usually put my cake in the fridg for a while to get the buttercream hard ... this way the stencil doesn't "stick" to the icing. Works great for me!! I have never used royal on it so I can't directly answer that question...

mcdonald - When you stencil, does the buttercream get really hard in the fridge? How long do you leave it in there?

I have stenciled with royal icing on buttercream and it worked great. Your BC needs to be crusted to prevent sticking. The RI should have a smooth consistency to spread evenly.