I have a surfing cake due next week and the cliet wants her husband to surf on a wave. It will be a half sheet cake, half beach and half water with a giant wave. For the wave I plan on using 50/50 fondant gumpaste mix and let it dry over a 2 liter bottle. What suggestions does anyone have on getting it to stay on the cake? The cake will be buttercream, so im going to try to blend it with royal icing, but I am worried that it will fall over on the cake. Has anyone done one of these before? How can I get it to stay on th cake securely? Thank you!

What about shaping the part of the cake into a wave itself? So for the beach part it's flat and then take some more cake and put it ontop (where the water part is) and carve it into a wave. That way you can cover it in fondant without having to use gumpaste and it's supported.

You might try small dowels in it, which then would go through the cake and help hold it up. If the wave is of any size, that's what I'd suggest.

Ever consider using modeling chocolate? It "dries" almost instantly, tastes infinitly better and is super easy to work with.

I would insert a couple of bamboo skewers or dowels into the bottom of the wave before setting it to dry.

The cake would be on at least 1" thick foamboard (2 layers of 1/2 inch glued together). Poke a couple of holes in the cakeboard and fill them with royal icing or melted chocolate. Insert the wave. Let the icing or choc firm up.

Cut the cake into pieces and arrange them around the wave. Since you're going to be making an imperfect surface (sand, water, etc), the piecing shouldn't be noticeable.

When you make your wave, rely on illusion. Don't make it top heavy or it may commit suicide on the cake!

thank you all for the suggestions!! I am making the wave today