How to Apply a Slurry to Concrete Countertops. Concrete counter tops are a great choice, because they are tough and need little maintenance. However, while the counters are unmolding, small air bubbles can form, creating holes in your counter tops. Applying a concrete slurry eliminates these holes and ensures your concrete counter tops look their best.
Take your set concrete counter out of the mold. Inspect the entire surface for holes or voids.
Grind your counter tops. Start with 50 grit sandpaper, sand several times with gradating grits of sandpaper. Finish with 400 grit diamond sandpaper.
Wipe off the entire counter with a damp cloth to remove any grit from the sanding and polishing.
Purchase a slurry formula and make a pure cement mixture following the directions on the package.
Apply one coat of the slurry with a putty knife. Allow it to dry for at least 2 days, depending on the humidity.
Sand again with 400-grit diamond sandpaper and then again with 800 grit diamond sandpaper. Apply a second coat of the slurry. You may need several coats depending on the amount and size of the holes left by air bubbles in your counter. Sand between each additional coat until no air holes remain.