I'm thinking of doing my first 3D cake this wkend for My son's b-day. I'm going to get the 3D car. Should I put it in the fridge for 24 hours to keep it moist and sturdy.... Also I'm really new at this and what would be the best "easy" frosting I can use make.....? TIA

I think as long as you keep the cake wrapped up nicely, you shouldn't need to put it in the fridge. Well, I guess it would depend on the day you bake the cake.

As for frosting, I've used the Wilton's buttercream. Half shortening and half butter. When I first started making frostings I couldn't ever seem to get it right. The Wilton's frosting was easy for me. There's a new buttercream everyone here seems to be raving about. It's called Creamy Dreamy Buttercream or Whipped Cream Buttercream Frosting, they're the same. Here's a link to the discussion on it. HTH!

http://www.cakecentral.com/cake-decorating-ftopict-11885-buttercream.html

would that be good in a bag too?

to keep the cake moist and sturdy, wrap it in wax paper and then plastic wrap while it's still warm, and stick it in the freezer.

if you're decorating using a star-fill-in or other piped technique, then go ahead and decorate it while the cake's still frozen.

you need a buttercream recipe that's fairly firm, as you don't want weepy frosting that won't hold up on the sides of the car (you can also avoid this by not laying on the frosting too thickly), so the wilton raw buttercream with 1/2 shortening should work just fine. children like this frosting as it's insanely sweet.

thank you!