I needed to fabricate an 8"x12" duct offset for a return I was adding. While this material did the job, I really wished that I went with 28GA or 26GA material, even with the small duct size I was dealing with. It is just so thin, it deflects and deforms very easily. That certainly makes it very easy to break and form, and it will serve it's purpose, but the 30GA thickness is a limiting factor here. I certainly wouldn't use it for fabricating anything over 12" wide.