When stacking cakes does there need to be a board in-between each set? Or can I just stack them on top of each-other with only buttercream separating them?
From what I have learnt you need to put dowels in (or I have seen a professional cake maker use straws) and a board.
Here is a youtube link and if you type cake decorating into the youtube search there is loads of stuff
Dowels in the bottom cake and a cardboard under the upper cake. Or a system like SPS.