Hi there! I want to make a dummy cake for this weekend. Having never made one I'm not sure where to start. I want a buttercream look but not even sure how to accomplish that and have it harden.

Would love peoples thoughts.

Hi, i,m sorry, are you wanting to decorate a dummy cake, or are you asking how to make a dummy cake. I can try to help you , knowing exactly what you mean.

If you use buttercream, it will dry and harden somewhat eventually.

You could use royal icing, Perma Ice artificial icing, or spackle from the hardware store.

Well the photo isn't uploading.

There we go! This is what I want to replicate. I don't think I could get the right look using royal icing. Not thick enough

One can certainly make dummy cakes using b'cream. As someone said, it eventually will crust over but never totally dry hard. If you look in my gallery I have many b'cream cakes - some of them dummy cakes that I did over the yrs as I prefered to work in mainly b'cream.
Use a recipe that has low fat and high sugar content. The less fat the more it will curst. Wilton's class b'cream recipe is good for what you want to do. Stay away from creamy recipes as they won't dry up enough.
If you have any more ?s please p.m. me but I'm only on the computer a couple hr a day so it might take me awhile to get back to you.