You can usually eliminate the humidity trapped beneath the sealer cures by applying acetone solvent on the surface. Start by applying the solvent on a cloth or dipping your brush into it. Then, rub the affected area vigorously with acetone product.
If the temperature is too low (less than 45 ℉) or the humidity is too high (above 65%), surface crust could form before the water can completely evaporate, thereby trapping the moisture and causing the sealer to dry a cloudy white or powdery color.
Concrete Sealers: Water-Based and Solvent-Based
The rest may occur when solvent-based sealers are applied in the presence of excess moisture. Powdery or white substance – The sealing agent evaporates faster than the water when there's too much humidity, so they never bond together, leaving this substance behind.
Those areas of delamination appear “white”. Tech Tip: If your sealer is solvent-based, use a xylene (or xylol) wash to re-solvate and redeposit sealer onto the concrete surface. If your sealer is water-based, this solution may work within the first 24 to 48 hours of sealer application.
If the temperature during application is too low or humidity is too high, the coalescing solvent will evaporate before the water does and the sealer will dry white or powdery because the latex particles did not fuse together before drying.
Apply Xylene to the problem area at a rate of 300 ft2 per gallon. Work in manageable sections that can be reached with a handled roller. Allow the Xylene to dwell for 1 to 2 minutes until the sealer has softened.
Clear caulk will come out white and dry clear in 7 to 14 days. Clear caulk is paintable but you will need to wait until caulk has become clear before painting it. Don't want to paint caulk?
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.
I asked Bryan if he could give us some insight on what it takes to actually remove a coat of sealer from concrete. He recommends starting with 2,000 psi and stepping it up to no more than 4,500 psi. The temperature of the water varies but is vital in this removal method.
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.
It can be just a white powder on your concrete, salt-like crystals, white fuzzy stuff, or what looks like white stalactites growing on your concrete wall. These white deposits happen when water is drawn out of cement material. It is called efflorescence, and it's not actually mold.
The chalking and dusting of the concrete is caused by a breakdown of the top surface area of the concrete. The surface of the concrete will erode easily under general traffic. This can produce a powdery, chalky appearance.
Water-based concrete sealers can be removed through chemical etching, aggressive pressure washing or mechanical scarification.
In these situations, use LastiSeal Brick & Concrete Sealer for an unbeatable 15-years of protection, or go for DryWay Water-Repellent Sealer, which is a DOT approved silane/siloxane water-repellent. Efflorescence is a very common and controllable condition.
But when a contractor is hired to renovate a dingy-looking slab of concrete, removing sealer is often part of the job. Sealers can be removed with mechanical means such as sandblasting or grinding. But for many contractors, it's a last resort.
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.
The easiest way to remove a concrete sealer is to begin by acid etching the surface of the concrete with muriatic acid. This process can be dangerous if you are unfamiliar with it; however, it is well within the ability of any ordinary homeowner, as long as the proper care is taken.
White vinegar will not damage your concrete. However, leaving this solution for an extended period will damage the cement that binds the concrete together. Hence, you should be careful when using vinegar on your concrete, especially if you will use this solution on polished concrete.
As moisture rises to the surface of the concrete, it carries with it the calcium salts from within the concrete. These react with CO2 at the surface, forming that white powdery dust. It can be worsened by exposure to moisture, such as rain.
Conclusion: Sealed enamel surfaces are prone to discoloration, which is most prominent in filled composite and glass-ionomer-based sealants. Staining can be reduced by polishing; however, in this in vitro setting the original color could not be restored.