Tin knocker is a slang term for a blue-collar metal worker. McDonald expands on this idea and makes rough representations of submarines, ships, and other military might. His assemblage technique is cold fastening (non-welded) tin and other raw materials by the use of screws, nuts, and bolts. Other ornamentations range from gas-can closures and car parts to copper wiring.
McDonald is fascinated with the build-it-yourself kits of his youth: Toggle, Erector sets, and model airplanes. These male-oriented toys introduced the artist to tools and materials as well as laying the foundation for creative thinking and problem solving.
Growing up during the Vietnam era with a WW II veteran father, it was easy to feed his fascination for American military apparatus. As he grew older, his political stance shifted. In the long run, this body of work is more about the art and the process if making it, versus the destructive reality of war.
McDonald further articulates, "I really believe the work is about capturing or re-capturing the innocence of being a child and perhaps the capturing of the projected innocence and assumed glory of American military power." His sculptures step into the personal realm-touching both the simple innocence of being a child and the mature understanding that comes with being an adult.