The acid etching process will remove the old concrete sealer completely from the concrete slab. In its place will stand a fresh slab of concrete ready for a new application of concrete sealer. Once the concrete has been acid etched, you need to let the slab dry completely before applying the new sealer.
Water-based concrete sealers can be removed through chemical etching, aggressive pressure washing or mechanical scarification.
You have some variety of choice when it comes to which products you want to use. You may have heard that it is possible to use muriatic acid to etch your concrete surface. Unfortunately, muriatic acid is often used because it's less expensive than professional products.
A strong enough power washer will blast most types of sealer off of concrete with ease. The trick is to make sure to pressure wash the entire surface area. For more sturdy sealers, it may take a few passes with the pressure washer to get it completely removed.
A simple floor stripper or paint and epoxy remover is something you can use to remove asphalt sealer. A caveat, though: you can only use paint and epoxy remover on concrete, metal, wood, and masonry. Do not use this on vehicles and walls as the product could strip the clear coat or paint off.
For some reason, this idea that vinegar will remove concrete sealer has become one of the more pervasive myths about concrete, and it is just that: a myth. That's because almost all concrete sealants are made to be resistant to acid, which vinegar is. As if that wasn't enough, vinegar can actually damage concrete.
When the sealer is applied too heavily, the air displaced through the surface can't escape, and it forms a bubble in the sealer surface. Bubbling of a sealer can also occur if application is done in hot weather, or if the concrete is in direct sun.
Sealers can be removed with mechanical means such as sandblasting or grinding. But for many contractors, it's a last resort. It destroys the original surface, exposes the aggregate and is a mess to clean up.
Soda blasting, a less aggressive mechanical method, has become more widely used in recent years to remove sealers and coatings successfully. Soda blasting utilizes special high-pressure blasting equipment with commercial-grade baking soda granules as the blasting medium.
Muriatic acid can work wonders on filthy concrete. However, it shouldn't be used on penetrating sealers since it can damage these finishes. It might also damage some acrylic sealers, so test a small area if you're not sure.
Neutralize with water and either baking soda, t.s.p., or ammonia and then final rinse twice with clean water only. We recommend using 12 to 16 ounces of ammonia per mop bucket. Or 6 to 8 ounces of ammonia to 1 gal sprayer of water.
Smooth Concrete Sealer Basics
Penetrating Sealers soak into porous concrete and masonry and create a permanent chemical reaction. They offer a flat appearance and protection that will only wear away if the substrate itself wears away below the level of sealer penetration.
Natural Stone Countertops. Granite, marble and concrete are porous. Spraying these surfaces with vinegar can cause etching and loss of shine.
Blotchy and Dark Concrete: Blotchy concrete can result from over application. In order to prevent over application, apply sealers in thin, even coats. If over application does occur, use Xylene to correct the problem.
Acrylic Concrete Sealers: Acrylic sealers last 1-3 years before they need to be re-coated. Epoxy Coatings: Epoxy coatings last 5-10 years before they need to be re-coated. Urethane Coatings: Urethane coatings last 5-10 years before they need to be re-coated.
Over time, heavy coats of sealer lose adhesion to the concrete surface and flake off.
Can I paint over the concrete sealer? You cannot paint over a topical sealer, so if you are painting, it must take place before the chemicals are used to seal. Concrete sealers come in many tints and will protect the paint underneath and avoid stains.
The acid etching process will remove the old concrete sealer completely from the concrete slab. In its place will stand a fresh slab of concrete ready for a new application of concrete sealer. Once the concrete has been acid etched, you need to let the slab dry completely before applying the new sealer.
The standard solvent bath process involves spraying store-bought xylene or acetone across the problem area. (As a side note, I do not recommend acetone, as it dries too quickly to be effective.) You wait a few minutes to allow the solvent to liquefy the sealer, then wipe or roll the area to eliminate the problem.
The acetone is great at removing sealers, super-strong adhesives. It may react with the tile, so you want to make sure that you try it first in an area and if you've got nail polish remover, in the house, with acetone give it a test.