Kevin walks through how he chooses the right gauge of metal for one of his sculptures …. In this how-tovideo, Kevin is beginning work on a 10-foot-tall sculpture called The Runner that he had originally designed for a public art project. Because of its structure, it requires a lot of initial thought about its proportions and balance. His first task is to scale up the sections of the sculpture from the maquette, or small model, to the larger version. It’s also a good opportunity to discuss a question he is frequently asked: how do you know what gauge metal to use? He shows some options – 1/8 inch plate, 20 gauge, inch-thick plate – and then shares his thought process in deciding which to use when. To create the full-size version of this sculpture, which was originally conceived for a public art project, he asks, “How big do the pieces need to be to make it proportional, stand up and still look right, like it’s balancing precariously, even if it isn’t?” To achieve his goals, Kevin decides to use varying thicknesses of metal. For the bottom of the base he’ll probably use 1/2-inch plate, because he wants the sculpture’s bottom to be big and heavy to give it a good solid footprint. Then he’ll use 1/4-inch for the sides and top of the base. He’ll add ribbing inside because, while there might not be a lot of weight to handle, there will be a lot of torque and leverage because of the shape and height of the sculpture. Then, when he welds the top plate of the base on, he’ll drill holes in it that line up with the base’s interior ribs so he can weld it securely and tie everything together to eliminate movement. For the next piece up, he’ll use 1/8-inch steel. The next block will be 1/8-inch steel where it ties into the block below it, but the rest of it will be constructed of 16 gauge. The next, large block will be all 16 gauge steel. The final block will likely be 16 gauge for the bottom panel where it ties into the block below it and the sides, but he may use 18 or 20 gauge for the top panel. Kevin reminds us that with gauges, the higher the number, the thinner the metal. So the metal the sculpture is fabricated of gets thinner as it goes up. This helps when moving the piece and putting it together – it needs to be light as well as structurally sound. Kevin will likely add ribbing inside additional blocks to help stiffen and strengthen them against warpage and flex. That strong structure will protect against high winds, climbers, etc. Another factor is whether you roll the metal, say in a slip roll. That work-hardens the steel, tempering it, and making it stiffer and stronger, with the curves working like the oval of an egg. So if he bowed all of the surfaces in this sculpture just slightly, he could choose a much thinner metal and make it much stronger, but the sculpture wouldn’t look quite right. Kevin says you’ll see more of this sculpture as he works on it all summer.
