How to Apply Acid Stain on Concrete?

The actual staining method is essential if you want to get the best results. If you want to stain a new concrete surface, make sure that it’s fully cured for a month before starting work. However, depending on temperature, type of concrete and the construction process, acid stains can be applied after 3 weeks. You should know that moisture content and humidity will affect the quality of the reaction. If you want the color to look consistent, make sure that the moisture level is equal throughout the surface. The spraying tool must not have metal parts, which could be damaged by acid solution and ruin the result of the work. Metal is dissolved in acid solutions, mostly producing metallic salts and water. If the acid stain already contains a lot of metallic salt, the color of the stain will not be satisfactory.

You need to spray with circular pattern, then with fine bristle brush you need to scrub the stain. After scrubbing the stain, you will need to have another spray pass to remove brush marks. By scrubbing the surface, you will ensure good penetration of acid solution into the concrete surface. If you want to get lighter colors, you can use reactive stain extender solution to dilute the acid stain. Although scrubbing the surface will help the solution to penetrate the surface, you shouldn’t scrub too hard, to minimize brush marks. When applying stain, make sure that you cover the surrounding areas, so you can avoid accidental staining. It will be quite difficult repair damage due to accidental staining.

Once the reaction of acid stain is complete, a layer of residue will form on the concrete surface. It’s the byproduct of the reaction process and still quite acidic. For this reason, you need to use neutralizer solution. If you don’t remove any trace of acid, sealer won’t be able to properly adhere to the surface. After applying the neutralizer solution, you can use a white cloth to remove any residue. Continue wiping the surface until there’s no more color on the cloth and it’s still perfectly white after wiping, then the surface is completely clean. It’s a good idea to use a pH meter to make sure that the concrete surface is completely neutral. When the pH value reaches around 7, then it should be a good idea to apply the sealer.

It’s not a good idea to completely waterproof the surface. So, you should use the acrylic sealer so moisture can escape from the surface. Instead of using water-based sealer, you should solvent-based acrylic sealers instead. For best results, you should apply a couple of thin clear acrylic sealer layers. You may also add seal floor finish solution which adds shine, while protecting the surface against daily wear and tear. If the concrete floor is located in a high traffic area, you should use high performance sealer. As an example, high performance sealer made from urethane and epoxy should work better than ordinary acrylics. Follow the label instructions to get the best results.

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