Robot BIrthday Party - Part I (The Cake)

To celebrate my son Dylan's 8th birthday, we had a robot themed party.  We chose grey and orange for the colors, I'll share some of the party details over the next week.  The details are my favorite part of planning a party. To start, this is the cake, we named him Robo.

I struggled to mix grey buttercream.  In the past, I have tried to make grey icing and it usually ends up being a light purplish color.  You would think that adding black food coloring gel would make grey - wrong.  With a little google researching, I found that others had experimented with adding a little yellow to the black as well.  I tried this, and I worked!  I'm really happy with the grey I achieved.

I made three rectangular cakes for the base of this cake.  One for the head, one for the body and one for the arms, ears and legs.