How can I make sure my castle cake doesn't collapse?

[mummyloveslucy]

Hi, I'm making a 2 tier castle cake for my daughters 7th birthday. I've made the towers for the bottom already, but I've noticed how heavy they are and I'm worried the higher ones might sink into the cake.
I've looked it up and the suggest dowling rods but I'm not sure how to use them. The towers will be made out of tubes, then the pointy bit at the top will probubly be a sugar cone, chopped down and iced. Would I need to securely stick that bit to the tower so that the dowling rod would hold the whole thing up?
Also, what's the name of the icing that dries very hard, that you use for decoration?
One last thing. The towers and things are going to be made ASAP, as they are not being eaten, but how long would a bought iced sponge cake last? I want to get it made as soon as I can to allow for any cock ups.
Thanks.

I would use a Madeira sponge recipe - keeps longer and the cake is firmer than a normal Victoria sponge. Do you mean fondant icing?

The dowels need to be placed into the bottom cake and they need to poke out slightly.

When is the birthday?

Thanks, that's great. Her party is on the 3rd March.

I did my daughter's third cake as a princess castle, all edible. It was put together as a round cake in the centre, with three towers, two at the front and one at the back centre of the cake.

To do this I made a heavier cake, madeira (which I soaked with vanilla syrup for moistness), two round cake tins for the main part of the castle, one on top of the other, sandwiched with jam and butter icing and covered in a pink rolled out royal icing. I also did one square cake which I cut into 9 circles with a large cookie cutter, then sandwiched three circles for each front tower and two on top of the main cake as the third. My glue was again jam and butter icing. Everything was then crumb coated and left to set in the fridge ( when cutting up the cake and working with it having it refridgerator cold makes it easier to handle too). I topped each tower with a cone, butter iced the towers in a contrast colour to the main cake, then added details like windows, doors, vines and flowers.

It stayed together very well, no need for dowelling or anything.

Use drinking straws as dowelling pegs. Use melted chocolate as glue rather than fondant or butter icing.

Yes, mini swiss rolls would be nice edible towers and less faff than dowels and cardboard etc. I hope your daughter has a nice birthday whichever way you make the cake.

Thanks everyone. Can you get white chocolate mini rolls? That would be perfect, if not, they'd have to be iced anyway to match the cake.

3rs March is a Saturday, so I would make the cakes now and put them in the freezer. Take them out on the Thurs, ice on Friday.