Most bombards started with the construction of a wooden core surrounded by iron bars. Then, iron hoops were driven over these bars in order to surround and cover them. The whole structure was then welded with a hammer while it was still hot at about 1300 °C (2350 °F). The rings then subsequently cooled and formed over the bars to secure them. The last step was to incinerate the wooden core and to attach a one-piece cast. The complicated procedure required a highly skilled forge who could work quickly and precisely with a hammer.