I've done cake dummies before, no problem, but I do have a question.
Sometimes the dummies are a little rough, not just on the edges but in general. Once the fondant goes on I'm questioning if I could put something on the dummie before I put the fondant on to look smoother.
I'm really curious about this because the wedding I have coming up will have a dummie cake under some of the cakes and I really want them to look as smooth as the real cake.
Cake dummies are often frosted to smooth out any flaws in the surface and to help the fondant stick. You can use regular frosting for the dummy tier in the wedding cake since it will only be around for so long. For display cakes, use shortening, which won't go bad. Mix the shortening until it's soft then frost the dummy thinly like you would crumb coat a cake.
No matter what you use to frost, I recommend putting a soup can on top of the dummy to weigh it down while you frost the sides, which will prevent the lightweight styrofoam from sliding around. Simply remove the can to finish frosting the top. Additionally, you may want to glue (with one glue dot or a touch of hot glue) your dummy cake to a cardboard base that is slightly larger. Then you will also have something to grab for leverage while frosting the top, moving the cake around, and delivering it. When it's time to assemble the cake, simply run the flat of the spatula underneath the cake to break the glue seal, taking care not to overturn the cake.
Hope this helps!
I just brush mine liberally with straight shortening and roll my fondant 1/16" thick. You can't see thru it at all and it's perfectly smooth. Only times I have problems is if there is a seam in the styro along the side from when it was made. I file that down and make sure I fill it with shortening, and if you can still see it I make sure it's in the back or covered with a flower.
I do just like FromScratchSF, for the most part.
I take every dummy and sand it lightly with fine grit sandpaper. I like using a sanding block. I smooth it out, taking down any seams and definitely decreasing the sharpness of edges & corners.
If i have a divot smaller than a dime, I fill it with some shortening. For larger divots, I use royal icing that I let dry and then sand flat.
I massage the dummy with crisco & apply the fondant.
Oh! Using Royal to fill holes is genius.