crumb coating/carving your cake

by Amee
(Ohio)

Hi, I'm trying to teach myself how to make some of the elaborate cakes, 3D with different types of decorations on them like gum paste and moldeling chocolate, but so far I'm having trouble with when to carve the cake pieces out and what to use to crumb coat them. Do I have to wait till the cake is cold before? Should I crumb coat it before I start to carve and then coat it again?
Also, what is the best frosting to use to coat the cake initially? I've been using a buttercream, but it seems to be pealing the cake with it. So am I not using enough, is it too thick/thin, is the cake not cold enough? I know that's alot of questions all at once, but I've been trying to research it and just havn't been able to find the right links on how the best way to do it is.
Thanks!!!