Concrete Etching Tips

This page is provided as a service to anyone who wants to learn about concrete etching.  If you are using muriatic acid, these instructions will work; however we recommend using Safe-React Formula E because risk of injury is dramatically reduced. Muriatic acid fumes present a significant risk to the health of the user. To learn more about Formula E click here.

Etching is a necessary step in most concrete finishing applications, such as painting or sealing.  The purpose is to open the pores of the concrete, creating a surface that a coating will adhere to. (Note: 2 part epoxy-type coatings are most reliable to last a significant period of time on concrete floors. Contact us to find one that is right for your application.) The following tips are not to be used as specific instructions, since concrete surfaces vary in many ways. Some are smoother than others because of techniques used during construction. They also vary in concentration of cement, admixtures, aggregate (such as sand and gravel), etc.  A small area can be etched initially to provide a feel for what concentration, duration and frequency will be used. You will have been successful when the surface is at least as rough as 150 grit sandpaper, water drops do not bead, and the pH is neutral.  The pH can be tested with a common paper pH test strip or pH pencil. 

When someone says "dilute x parts muriatic acid with x parts water" they are talking about starting with the commonly available form of muriatic acid, which is approximately 36% strength.  Safe-React Formula E is formulated to identically replace the commonly available form of muriatic acid.  Therefore, when following traditional instructions for diluting muriatic acid such as for pH adjustment, cleaning, etching, etc. the identical formulas can be used. If you are an etching veteran and you normally dilute muriatic acid with 10 parts water, do the same with Safe-React Formula E. We tend to have better luck and more control with higher concentrations, such as 1 part Formula E to 2 parts water or slightly weaker. Time of exposure is the only factor that varies, compared with muriatic acid. Safe-React Formula E will take slightly longer to do the same task as muriatic acid. Users find that allowing 30% longer exposure will suffice.

Before etching, remove dust particles by sweeping thoroughly or pressure washing. If it is not a new installation, grease, oil, mildew, and any other foreign matter will need to be removed with an appropriate cleaner (degreaser, mildew remover, etc.). Before you begin the next step, read the MSDS of the product you are using and use appropriate safety equipment such as rubber gloves and boots, goggles, etc. Although Safe-React Formula E is DOT non-hazardous, it is a skin and eye irritant. We recommend that you dilute Formula E with approximately 2 parts water. Add Safe-React Formula E to water, not water to Formula E. Spread this mixture on the concrete floor, working with a small area at a time. A large acid brush with a long handle, working out of a plastic bucket performs well and allows the solution to be worked into the surface. Some users prefer to sprinkle the solution onto the floor using a plastic plant-watering can with sprinkle-type spout. The objective is to just cover the surface with liquid, which will bubble or "fizz" on contact. You do not need to put enough to create puddles. On the average, coverage is approximately 1 gallon of the final mixture for 100 square feet of floor surface. Allow this to remain for 20 minutes (less time if you are using muriatic acid).  Rinse the surface with water.  If etching a large area, a system of rinsing can be developed where a second worker follows 20 minutes behind the etching worker, using a hose with a closeable nozzle and a squeegee to prevent the new applications from being diluted prematurely. 

The final step is neutralization. Mix one quart of non-sudsing household ammonia per 5 gallons of water. Spread this with a mop to mix all around for uniformity (this step involves more liquid, and can be allowed to puddle). The pH of the remaining liquid should be between 7 and 13. 
Some surfaces require repeating the etching process. Squeegee and allow to dry thoroughly before applying coating.   

Environmental note: In most municipalities Safe-React Formula E can be legally washed down the drain if the pH is first adjusted to neutral, or at least above 4. It is best to keep some pH test strips to monitor any runoff.  There are no heavy metals, phosphates or hazardous elements present. The user is responsible for compliance with all local, state and federal laws in the location of use.  Many customers have asked about grass and other plants growing near their concrete job. The risk of damaging them with Safe-React Formula E can be reduced if you first sprinkle lime or soda ash on any part of the plants where the liquid may contact and continue to rinse with water afterwards. Again, this adjusts the pH.

Shield Industries Home|Safe-React Products Home|About Us|Contact Us

Shield Industries, Inc © 2008, All rights Reserved