Forgive me I'm new. I have been reading in the forums and I saw people talking about non crusting buttercream and crusting buttercream. I have never heard of them before. Can someone please explain?

Crusting bc actually dries and 'hardens' somewhat so that it is easy to decorate on and you can smooth it. Non-crusting bc stays soft and is a little more difficult to work with, but tastes great! You can smooth it somewhat. Not sure if this helps.

Are certain types of buttercream crusting and others aren't ...Or are there specific recipes for each? Sorry to sound so dumb.

Alot of buttercreams that have butter/crisco and powder sugar will crust. It is the ratio of fat (butter/crisco) to sugar that factors in to the crusting. A recipe that has a cup of fat to a lb of sugar will crust. The more sugar the faster the crust. The more fat the slower the crust and in some cases won't crust.

Cooked recipes that contain egg whites and granular sugar like Swiss or Italian Meringues do not crust.

Thanks! that clears it up!