Iron vitriol gives patina and a certain protection. Iron vitriol powder is dissolved in hot water. The mixture is applied onto new timber with a paint brush. After a few months, the wood is gradually changing color and assume a gray shade - the stronger the concentration, the darker wood. Iron vitriol is an outdoor product and should not be used indoors. Treatment need not be repeated.
Recipe: 10 lb of Vitriol powder dissolved in 24 gallons of warm water is enough for about 2000 sq ft of surface area. You can add a small amount of the light or dark pine tar to the solution as well as some organic raw linseed oil. The organic raw linseed oil added will prevent the wood from cracking. The organic raw linseed oil will darken the color.
Great variations can be created by adding more or less of the light pine tar and organic raw linseed oil. Iron Virtriol itself is colorless so the gray color comes with time.
This is an effective and very economical water-based wood product composed of minerals and natural plant substances. Wood treated with iron vitriol has flame retardant properties and improved resistance to rot.
 
Free from hazardous heavy metals, biocides and solvents classified as Good environmental nature protection.
 
Treated wood gets a bright, smooth surface that ages beautifully with time aging to a natural silver-gray.
 
Ideal for use on wood siding, decks, docks, fences, wall panels, furniture etc.
 
Always do a test to avoid unwanted results on you final project.