How does acid staining work?
Metallic salts are the ingredients that actually color the concrete. These salts, in an acidic, water-based solution, react with calcium hydroxide (hydrated lime) in hardened concrete, creating insoluble colored compounds that become a permanent part of the concrete. The stain can take as much as a month to fully develop, and the outcome can depend on several factors including the composition of the concrete, the age and moisture content of the concrete, whether conditions at the time the stain is applied, and more.
