Muriatic Acid

Midwestpro · Posted: Fri Mar 28, 2008 1:01 pm Post subject: Muriatic Acid

Muriatic Acid also known as Hydrochloric Acid, must be handled with appropriate safety precautions because it is a highly corrosive liquid.

Hydrochloric acid is produced in solutions up to 38% HCl (concentrated grade). The acid is available at most hardware stores at a concetration of 31% HCl, which is commonly used to adjust the pH level in swimming pools.

In the pressure washing industry, Muriatic acid is used to etch concrete before sealing it. Concrete sealer adheres better to concrete that has been etched. When etching, the acid is actually removing a microscopic top layer of the concrete, exposing a clean fresh layer that is slightly more abrasive than the old smooth layer.

The concrete should first be cleaned to remove all dirt, mold, and mildew. Read more here for effective concrete cleaning tips.

The most efficient way of cleaning concrete is by using a concrete cleaning tool known as a surface cleaner. After cleaning the concrete entirely and rinsing thoroughly, a diluted solution of Muriatic acid is applied to the concrete. If you used a bleach solution to clean the concrete be sure to rinse extremely well because Muriatic and bleach should not be mixed.

For etching concrete use 1-pint of Muriatic Acid per 1 gallon of water and apply with a scrub brush or acid resistant sprayer. Mixture should create a white bubbling reaction on the surface. Allow mixture to stand for 5 minutes and rewash concrete again, using a pressure washer. Rinse thoroughly and allow to dry for several days before applying concrete sealer. Etching is only necessary and smooth concrete surfaces such as porches and patios.