Below is a list of Copper Sheet manufacturers from Petaluma, California. Copper sheets are large, thin planes of the popular non-ferrous metal known as copper or one of its many alloys. A common stock shape, metal sheets offer thicknesses greater than that of foil, but thinner than copper plates. Copper planes of thicknesses between 0.006" and 0.250" with a width of 24" or more are typically considered to be sheets, though regulations and categories may vary among manufacturers.