Concrete Etching

• Some municipalities restrict disposal of acidic etching solutions. Contact your local wastewater management agency to see what regulations cover concrete etching. Remove everything from the floor of the garage and use a stiff nylon bristle broom to clean out as much loose dust and dirt as you can.
  
  Concrete etching uses muriatic acid, which is 30 percent hydrochloric acid. When working with acids, personal protection is essential: eye and face protection, rubber gloves and boots and, if possible, an acid-resistant bodysuit. When working in an enclosed area such as a garage, a facemask with acid vapor filters will protect your lungs from the corrosive fumes. Safety gear can often be rented from a local building supply store. Undiluted muriatic acid will quickly damage the concrete, so plan to dilute it with ordinary tap water. Most concrete surfaces can be etched with a mixture of one part acid to three parts water, but particularly hard or smooth concrete requires a solution of one part acid to two parts water. When diluting acid, slowly pour the acid into the water. Never pour water into acid: a violent reaction could occur.
  
  Acid is less effective in cold temperatures, so choose a day above 50 F (10 C) to etch your floor. Use a garden hose to wet down your garage walls, driveway and nearby landscaping. Keeping these surfaces wet helps dilute excess acid. A slurry of baking soda and water placed at the edge of your garage neutralizes acid before it marks your driveway. Use a plastic watering can to spread the acid over the concrete and then use your stiff broom to work the etching solution into the microscopic cracks and pits of the floor. Scrub from the front of your garage to the back and then from one side to the other. Let the acid work for about half an hour. This is a great time to apply another coat of water to your driveway to prevent the acid from causing streaks. Then use your hose to thoroughly dilute and rinse the acid mixture out of your garage. Let your floor dry before applying epoxy sealant, but keep the garage door closed to keep dust out.