The zinc coatinp shall be apnlied directly to the sheet steel bv immersing it into a molten zinc bath. On withdrawinp the sheet from the zinc bath, treatment with steam or air wi1.lhe permitted to effect minimized crystal size in the zinc coatimp(minimized spangle). Rolling to improve smoothness of the coatine trill also be permitted. The coating, immediately prior to solidification, shall not be subjected to mechanical wiping or scrapinp, to achieve smoothness, 3.3 Coating thickness. Unless otherwise specified, the thickness of the zinc coating, on each side of the st.eel sheet shall averaRe 0.67 mil (17 microns).