Hi!
I am not a professional baker, but enjoy baking and decorating my kids cakes..I have made lots with fondant but never a stacked cake that required any dowels or boards etc. The cake is R2D2 from star wars. So it's about 6 9" in round cakes stacked on top for his body. There will be buttercream in between the layers and coated with fondant but I am totally lost on the kind of support this would need. I've seen the plastic tiers and dowels and then wooden dowels..but am not sure how much support I would need for a cake like this..I am making it home for a party here so I won't have to transport it...Will it cave if I stack these cakes without these boards/tiers in between? I'm going to try to attack a pic/link so you have an idea what kind of cake I'm trying...
I truly appreciate any help/feedback because that last thing I want is to spend two days making this for my son for it to collapse!!![
HERES SOME EXamples: IT'S BASICALLY A 3D R2D2 SO ANY OF THESE IMAGES GIVES YOU AN IDEA..
http://www.coolest-birthday-cakes.com/coolest-r2d2-cake-33.html
http://www.coolest-birthday-cakes.com/star-wars-cakes.html#c1

Use a support system for every 4" of cake height.

I just made an R2D2 cake a couple of months ago. I wish I had a picture of it to show you. I used 6 2" layers of cake for his body and carved a wondermold cake for his head so technically 7 layers. I used a cake board and wooden dowels cut to length for every 2 layers (4") with a long sharpened wooden dowel rod going through the whole thing as I had to travel about 2 miles away with it. My husband also built a wooden platform for the cake to sit on with feet and arms that we covered with rice krispie treats and fondant. It was my first 3D cake and it was really quite easy to make. I highly recommend finding a battery operated LED light to put in for his eye. Also my husband's idea and everyone loved it! I'll try to find a picture of it and post it later. Good luck!

As the others have said, it's best to use support/doweling every 4" you go up. So one would have cake, filling, cake w/support; cake on a cake circle, filling, cake w/support.
Since this cake is not going to be transported you don't need a long dowel thru the center.
For doweling/support I recommend using fat plastic drink straws - like the ones McDonalds (and other fast food places) have. Push one straw in very straight and cut off at cake level w/scissors. Now use that to cut the others for that cake so they are all the same height. For cakes up to 9" round 5 straws in each is fine. Place them around an 8" circle for 9" cakes. Each 4" cake's straws should be measured separately as they might not be exactly the same height as the other cakes.

Thank you for some responses alrea[list=]dy...
[u]jamawoops - If you find a picture I'd love to see it!

So if I use the fat straws through the cake, do I need boards or anything in between layers or am I just using the straws? I don't know why this is so confusing to me but this is a whole new element from having fun decorating with frosting and fondant[/list]