I am inexperienced with working with fondant. I made my first attempt at MMF the other day on a "trial" cake. I thought that I rolled it to 1/16th but it seemed to not be thick enough on the cake....the buttercream was oozing out of the impressions that I tried to make on it. I am wondering if my "crumb coat" was too thick...What should it be under fondant? Also what should the thickness of the MMF have been? If I am planning to make impressions (in this case diamonds) should I roll out the MMF thicker?
Thanks for your help!

Hi there,

Your crumb coat should be just thick enough to give you a nice smooth surface for your fondant. It also needs at least 2 hours to settle and crust up before placing the fondant. It does sounds like your fondant is a bit too thin tho. I roll out mine so it's about the thickness of a quarter.

I usually let my cakes rest at least 4 hours, usually overnight, (because I have had that happen to me before) then put my final coat of bc and roll my fondant to about 1/4 inch.

I put a nice thick coat of buttercream on and then chill the cake until firm. My fondant is usually about 1/8" thick unless I have dark buttercream and light fondant, then I roll it thicker.