Canvak canvas wax is a refinishing compound that restores water repellency to cotton fabrics. It is a semi-clear solution and can be applied to any color cotton canvas. Canvak is wax based and this may leave a water repellent film on the fabric. Shelf life for this product is indefinite as long as the container and liquid is not exposed to extreme conditions. Retreat your canvas tents or tarps with the great finishing agent and make them water resistant once again. Canvak should be not used on vinyl finishes of fabrics or synthetic fabrics. If you were wondering how to waterproof canvas, then this is the ideal solution for you!