Acid etching gel concrete is a safe and effective method to remove oil, grease, and other surface contaminants from your garage floor. It can be used on either green or aged concrete.
The process involves applying an acid solution to the concrete and letting it work for 15 minutes or so. Then rinsing it off.
Preparation
Acid etching is the process of applying buffer phosphoric or muriatic acid to a concrete slab in order to open its pores and prepare it to receive a protective coating. The chemical reaction of the acid solution on the surface of the concrete creates a rough surface profile that is suitable for thin coatings, but is not recommended for thicker resinous flooring systems.
The acid etching process should be done by trained professionals, because over-etching can corrode metal rebar, weaken the concrete and lead to structural failure. If this happens, the entire slab will need to be re-prepared. This can be a costly, time-consuming and frustrating process.
Before applying the acid etching solution, it is important to properly remove all oils, greases and sealers from the surface of the concrete. This can be accomplished by scrubbing the surface with a degreaser, sweeping it or shop vacuuming it prior to applying the acid.
When applying the acid etching mixture, it is imperative that you apply it evenly over the surface of the concrete. This is accomplished by using a plastic watering can that allows you to distribute the acid uniformly over the concrete.
Once the acid has been applied, it is important that you keep it on the surface of the concrete for at least two to ten minutes before rinsing it off. You will notice that the solution will bubble and react with the concrete, indicating that it is successfully removing contaminants. If there are any areas that do not bubble or simply “bead up” on the surface, this indicates that contaminates are blocking the acid from penetrating into the concrete.
If any puddles or pools of water are left on the floor, squeegee them away. This will prevent the acid etching from penetrating too deep into the concrete and making the concrete more porous.
To ensure that the acid etching solution does not over-etch the concrete, it is essential to mix the acid at a low ratio (one part acid to four parts water) and add only enough water to bring the solution to a 10% solution. If the acid etching solution is not mixed at a low ratio, it may etch the surface deeper than necessary and soak into the concrete and contaminate it after floor materials are applied.
Application
Acid etching gel concrete is an acid based product that can be used to remove stains and blemishes from a concrete surface. It can also be used to etch detailed designs or to expose aggregate for design purposes.
Before applying the product, make sure to wear all necessary protective gear (gloves, safety glasses, and boots) and ensure that there is plenty of fresh air to ventilate yourself properly. This is important to prevent any chemical burns or other damage to your skin and eyes from the fumes generated during the application process.
Once you have all your protection in place, pour the appropriate amount of acid etching solution on the floor and evenly distribute it using a squeegee. This will ensure that each part of the floor is covered by the solution. You should see the solution bubbling as it reacts with the concrete. Once the foaming stops, it is time to rinse the surface.
The rinsing of the surface must be thorough in order to remove any residue from the acid etching process. This is because a residual cleaner can stop the coating from bonding properly.
A concrete surface that is etched with the proper acid concentration and a neutralizing solution should have a smooth, open, porous, uniform texture similar to medium-grit sandpaper. A water-beading or breaking concrete surface is a sign that the etching process did not achieve this profile.
If the rinsing process does not completely remove the residual acid and any debris from the surface, a re-etch should be performed. Repeating the rinsing process until the profile of the concrete is consistent with the required degree of profile as described by the coating manufacturer will help ensure that the surface is ready for the application of the final coat.
Alternatively, if the concrete is heavily textured, the surface can be ground to achieve this goal. This will require more time and effort than simply removing the latencies with acid etching, but will produce a more even surface for the coating to adhere to.
The etching process should be completed in two to ten minutes, depending on the strength of the mixture. You should not leave the solution on any part of the concrete for more than this period of time.
Neutralizing
Before applying any etching gel concrete, ensure the surface is clean and free of any oil or grease. This will help prevent unevenness and uneven etching results. Sweep the floor thoroughly with a broom or a squeegee to remove all loose dust and debris that may be blocking the acid from reacting properly with the concrete.
If you have greasy or oily spots on the concrete, use an industrial degreaser to remove them. This will help the acid react more evenly with the concrete and provide a better, cleaner surface for the etching solution to work on.
Once you’ve removed the dirt and grime, mix up a neutralizing solution that is made up of one cup household baking soda per gallon of water. This will help neutralize the residual acid that’s still lingering in the pores of the concrete after you rinse it off with water.
After the baking soda is added, you can rinse the entire area with a shop vac or squeegee. If you have a pressure washer, that’s fine too, but you’ll want to be sure to flush it away from the concrete and not let it run down the drain as this can drive any leftover acid deeper into the concrete and cause problems later on.
The rinsing process should be done in stages and the last stage is to test the pH of the wet concrete using a simple pH test strip. Anything below 6.0 indicates that the acid residue is still in the pores of the concrete and needs to be neutralized.
This can be accomplished by rinsing with a lot of water and then letting it sit for a few minutes until the water starts to evaporate. This will help to neutralize the acid so it can be disposed of properly.
You can also choose to use a specialized product like Rust-Oleum’s Clean & Etch. This is a great way to save time on the cleaning and etching of your concrete while being safer than other options. This is especially useful if you have children or pets that can’t stand the fumes of many other etching products.
Rinsing
Etching gel concrete removes rust, mold, mildew, efflorescence and other surface contaminants. It also opens the pores of the concrete so a coating can adhere better.
It’s also a good idea to use this process to prepare a concrete surface for painting. It will help the coating adhere to the surface of the concrete and eliminate laitance, a milky deposit of cement dust, lime and sand fines that can build up on a fresh surface.
You can use a liquid or powdered acid etching solution. DRYLOK(r) offers both ready-to-use sulfamic acid liquid and powdered concrete and masonry etching solutions that are safe and easier to use than muriatic acid.
Using a hose with a sprayer attachment, wet the concrete to a level of wetness where no standing water remains. This is important because it reduces the chances of any acid contacting the floor if you etch up to an adjacent surface.
Once the sulfamic acid solution has been applied to a section of concrete, it should begin to bubble and react with the concrete. This will indicate that the product is reacting correctly with the concrete and will allow you to start rinsing.
If the acid etching gel begins to foam or beads up on some areas of the concrete, agitate it with a push broom and continue rinsing until the surface is uniformly etched. This may take up to ten minutes.
At this point, rinse the area with clean water. Rinsing the floor thoroughly ensures that no etching product is left behind in the pores of the concrete.
This is a very important step and it is critical to the results you get from this process. If buy lsd gel tabs don’t rinse it thoroughly, the acid can seep into the concrete and cause problems later on.
When the rinsing is complete, check the pH of the acid solution by placing a pH test strip on the still wet concrete. Any reading below 6.0 indicates that there is some acid residue remaining in the pores of the concrete and it needs to be neutralized.
Once the pH is at a 6.0 level or lower, rinse with clean water and repeat the process until the pH is at an acceptable level for the coating you’re applying. For most coatings, a pH of 7.0 (neutral) is sufficient.