I have an order for a fondant cake this wkend, and I would like a few pointers on how to prevent a sag.
When I've covered cakes with fondant in the past, I always seem to get a sag around the bottom edge of the tier. The sag seems to appear after the cake has been sitting a few hrs. I use a cake board that is smaller than the cake, apply a very thin layer of buttercream btw the cake & fondant, & let the cake sit uncovered to get rid of moisture. I also let the cake settle several hrs to overnight after it's filled. I've used Satin Ice, MMF, MFF, and Fondyx with the same sagging results.
What could be the problem? Should I make the cake circle the same size as the cake? Wouldn't that create a shadow? Could my fondant be too thick or thin? In the past, I've been able to hid the sag with a large border, but I would like to use a smaller border.

Thanks!!

check this out if you haven't already - ganache might cost a bit more, but the result...!
http://www.cakecentral.com/modules.php?name=Forums&file=viewtopic&t=633264&postdays=0&postorder=asc&&start=0

Are you making sure that you "adhere" the fondant to the entire side surface of the cake with fondant smoothers?

Also, if the bc crumbcoat has crusted before you apply the fondant, this could cause the fondant to not adhere enough which would result in sagging or pulling away from the cake.

If the crumbcoat does crust before you have a chance to apply the fondant, just mist it with a spray bottle of water.

Other then that the only thing I can think of is the thickness of your fondant, maybe it's too thick. You could try rolling it out a little thinner.

HTH

in addition to the above advice, you need a firm sturdy cake and a thickened dam tpo prevent the filling from squooshing out.

HTH

I would go with Sugar Shack on that one. Cakes tend to compress after sitting for a few hours, especially once you add the weight of fondant. Make sure you're using a cake that is stiff enough to hold it.