My son really loves Transformers but all the costumes out there looked so cheap. This Transformer Kids Costume Idea took about 3 weeks but I did not spend more than a couple hours a day on it, and a lot of that time was waiting for the paint and glue to dry.
First I looked at tons of pictures on-line to get an idea of how we wanted it to look. I was going for more of the older Transformers look from when I was a kid, which was boxier. The body is a diaper box with tissue boxes cut in half for the shoulders. I attached the shoulders separately with a duct tape 'hinge' to make it easy for his arms to go in. The shoulders would lift up to get his arms through the holes in the side. The feet and arms were also halved tissue boxes and the feet were hinged with brads so he could actually walk in it. The exhaust pipes were painted paper towel rolls, and the headlights (small smoothie containers) had small mag-lites in them so they really lit up. I used craft foam for the hip area and the details on the feet. The hip area was fastened on with velcro so we could remove it for him to sit. I had no idea what to do for the wheels and then luckily we got some fast food containers that fit perfectly. For the windows I simply used black construction paper that I slide into clear page protectors to give them a reflective, realistic look. He already had the red turtleneck and gray baseball pants.
The only thing I had to purchase was the mask and some paint! It took several coats of paint to cover all the boxes completely. My son is thrilled with it and all the neighborhood kids love it.