Preparation : Dissolve 60 to 80 g of Iron Sulfate in 1 liter of water. It will result in a greenish water. One coat of Iron Sulfate solution for a very tannin wood like Oak, Walnut, mahogany and Cherry wood will give a silver gray to a blue steel color.
Species such as maple, beech, birch or cedar will have a less pronounced color due to the low level of natural tannin.
Caution : Handle with care, work in a ventilated area, wear protective glasses and gloves.