Slate is a metamorphic rock mainly composed of calcite, quartz and mica. It's generally used in the production of items and structures, including gravestones, roofing tiles and flooring. The natural rock is durable but porous, requiring a sealant to protect it from water damage. Tung oil, otherwise known as China wood oil, is a viable option to seal slate because it creates a watertight barrier on its surface while minimally changing the rock's natural color.
Things You'll Need
2 boxed fans (optional)
2 cups tung oil
2 cups paint thinner, citrus solvent or mineral spirits
Wooden stirring stick
Put on a pair of rubber gloves, dust mask and safety goggles. Ventilate the space by opening a window or running one or two boxed fans. The products used to create the homemade sealant create unpleasant fumes and odors, requiring these necessary precautions.
Create a mixture of 2 cups tung oil and 2 cups paint thinner, citrus solvent or mineral spirits in a container.
Stir the mixture together with a wooden stirring stick until completely incorporated. Spread an even layer of the mixture onto the slate tile with a paintbrush. Avoid overloading the tile with the product, as it won't completely seep into the porous slate, resulting in an unwanted mess.
Allow the first layer to soak into the slate for three to five minutes before wiping away any excess with a rag. Allow the first layer to dry for at least three to four hours before applying at least three to five additional coatings.
Allow the final coating of sealant to set for at least 48 to 72 hours before stepping on the slate floor.
Tung oil is available at home improvement, hardware or woodworking stores.
Citrus solvent is less toxic and safer than paint thinner or mineral spirits, but it is not always readily available.