Etching a concrete surface before applying paint is very crucial.
Acid etching of concrete exposes the pores of the concrete and prepares it for other treatments.
How to etch concrete with muriatic acid?
Clean and dampen the concrete to etch the surface properly. Apply acid on the surface with a ratio of 3:1 of water to acid. Scrub the solution into the concrete surface. Make a neutralizer solution to wash off the acid solution. Rinse away the residue and test the pH level of the washed-away water.
Too much to understand? Don’t worry! This step-by-step guide will guide you through.
Without further ado, let’s get started!
Let’s Etch Concrete with Acid
A smooth concrete floor will not have a paint stick to it. It needs to be roughened. Thus you need to etch the wall before painting. Muriatic acid plays the role of liquid sandpaper and roughens the surface.
It also reduces the alkalinity of the surface. This helps the paint to sit well on the surface even more. Muriatic acid is hydrochloric acid in liquid form. So you also need to be very careful while handling it.
Now, let’s jump right into the detailed steps!
Step 1: Clean the Surface
Cleaning the surface is a must and also the first step. Check for dirt, oil, or any kind of contamination, You may also use an abrasive cleaner if there is heavy dirt on the surface.
Step 2: Dampen the Concrete
Dampen the surface you want to etch with clean water. Try to equally dampen the whole area of the surface. If some places are dry or overwet then it might cause issues for you while etching.
The surface needs to be wet while you etch it. So you can also divide the area into smaller areas for your convenience. You can then etch them once at a time without losing track of the area.
Step 3: Applying Acid on the Surface
The ideal ratio of the acid solution is 3:1 of water and acid respectively. Use a 2 gallon of water container to spray the solution evenly throughout the surface.
Spraying it will make the solution evenly spread instead of splashing it to a certain area. Remember to not directly pour the solution.
A 2-gallon water container also works well because you can make a solution easily. 1.5 gallon of water and .5 gallon of acid makes the perfect solution. But you can make any amount of solution as long as the ratio is right.
You can also make use of some other containers with sprinklers. Here are some recommended ones:
Step 4: Scrub the Solution to the Ground
After applying the solution to the ground gently scrub it into the concrete surface. You can use any kind of scrubbing tool with a long or short handle. The muriatic acid will thoroughly clean the concrete wall.
Let the solution sit on the surface for at least 10 to 15 minutes. The solution will fizz and bubble up. Make sure the surface doesn’t dry out and add more solution if needed.
Step 5: Neutralize
Once you’re done with scrubbing the solution to the ground it’s time to neutralize. Add one cup of baking soda with 1 gallon of water. Fill the empty water container with this solution.
Now, spray this solution on the surface that was etched with acid and let it sit for 10 mins. When 10 minutes are over, rinse the surface and remove the neutralized solution. You can also use a wet vacuum to do this procedure.
If your wall has paint on it then make sure to get the paint off of the concrete.
Check the surface after all this process. Make sure it feels like moderate grit sandpaper. Also, it should have a uniform texture. If it’s not the way it’s supposed to be then repeat the process.
Step 6: Final-Rinse
Once the neutralizer solution is cleaned up, give it a thorough rinse. It’s important to remove every bit of solution from the surface. Do it as many times as needed to completely clean the surface.
Generally, it leaves a white powdery residue if not cleaned properly. The powdery residue might be problematic for your paint to sit properly later on. Using a high-pressure nozzle while scrubbing your surface is a good idea.
Step 7: pH Test of Your Rinsed Water
Test the pH level of the freshly rinsed water. Put a pH strip into the rinsed water. Read the pH strip to know the pH level of the water.
The pH level should be between 6.00 to 9.00 for most surfaces. While 7.00 is the ideal level. If it’s lower than 6.00 then it means there’s still residue left on the surface pores.
So rinse the surface again until you get the desired result.
Is it possible to etch a painted wall?
Answer: No. If the wall is painted then the liquid can’t reach its intended target. Also etching is required for paint to sit well on the surface.
Can I mix paint with the solution to etch while designing?
Answer: No. Mixing paint with muriatic acid will make the paint useless chemically. So it can’t be done
Is there any alternative to muriatic acid for etching?
Answer: Yes. If you are intending to avoid acid then you can use an Eco-Etch-Pro. It’s even better because it’s a biodegradable, non-hazardous concrete etcher.
Here you have it. You’ve successfully etched your concrete wall with muriatic acid. Hopefully, I addressed all your concerns regarding how to etch concrete with muriatic acid.
If you’re unsure about your skills then do contact a professional. Working with muriatic acid can be quite risky.
Good luck and see ya!