Lead Naphthenate (24%)/3.36 The base is ground in a pebble mill to a fineness of 5.5 on the N.S. gauge. B Letdown "Cab-O-Sil" M-7 Mineral Spirits "Polyurethane 101" "Polyurethane 101"/318.0 Mineral Spirits/66.5 Cobalt Naphthenate (6%)/1.12 Manganese Naphthenate (6%)/1.12