we were just on vacation at Disney so I didn't want to get too elaborate due to time constraints. My son asked for a tank cake. I'm sure he would have been happy with a cake with a picture of a tank on it or a model tank. But I would not have been happy. First I decided that the turret would rotate. That is pretty easy. I toyed with the idea of having it shoot something (what says happy birthday more than getting shot in the face with whipped cream) That idea got shelved as soon as I imagined the look on my wifes face. To up the difficulty level I decided to make the gun go up and down as the turret rotated.
-Imagine wife smiling-
It is a little difficult to see the gun raising and lowering due to a bad camera angle. Look at the camo icing and the gun shield and you can see what is happening.
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Step 1: The mechanism
By the way, nothing puts a smile on my face more than describing how I make cakes with a welder:)
To make the gun travel up and down, I decided to make a rod and cam type system. I welded a guide tube to the turret pan and made a "cam" of sorts out of a metal disk that I heated with a torch and bent randomly. I then fixed this to a tube that would act as a bushing for the turret pan rotation.
I had a slow turning motor sitting around the house and mounted it to a piece of wood as a base. I welded legs to the cam and drilled them into the wooden base. I set it all on a bit of an angle so the tank would be tilted slightly when done. You can see that the turret pan warped a bit during welding but I was not too concerned and I did not bother to correct it. The push rod was installed to slide along the cam and raise the barrel.
The last thing I did was put on the barrel guard. I used perforated steel for two reasons, one was it would be really easy to bend a slight curve into it and two was so the icing would have something to adhere to.