The fiberglass coil form in the mold. The mold is sheet metal rolled up and held by the plywood. The sheet metal tube was lined with mylar film. The mold has a disk at each end to make an internal flange on each end of the finished fiberglass. The finshed fiberglass is 30 inches long and 20 inches in diameter. Two of these were joined to make the coil form 60 inches long.