All surfaces should be clean, dry and free of any debris prior to application. Sand down or fill with slurry all “pinhole” air pockets or voids in the countertop surface prior to application. Sand and repeat until all pinholes and voids are filled. The surface should be polished to no more than 200-grit prior to sealing. See our video, How to Make and Apply a Countertop Slurry Parts 1 and 2, for more information.
As a two-part system, Part A must be thoroughly mixed into Part B in order for the material to properly set up for application. Stir part A with the wooden stir stick prior to adding part B as settling can occur. Mix three Parts “A” to one Part “B” in a separate container for smaller projects. Immediately replace each lid tightly. For larger countertops, add the Part A into Part B and begin to mix with a wooden stir stick. Mix completely; fold the material over onto itself and carefully scrape the sides of the can to assure nothing is left unmixed. The contents should thicken and become whiter as you stir. Stir for 2-4 minutes until totally combined. Once mixed, the pot life for the sealer is approximately 1 hour.
When applying in optimal temperature and humidity conditions of 75 F and 50% humidity, 550 Polyurethane pot life is approximately 1 hour before the material begins to harden. Do not apply to surfaces below 65F or above 90F or if humidity levels are above 80%. Lower temperatures will maximize pot life and higher temperatures will reduce it. The sealer itself must be above 60F before installing.
Water-Based Polyurethane Sealer can be applied either with a de-fuzzed 3/8″ nap roller or with HVLP Gravity Feed Spray Gun with compressed air for finer finish. For complete application instructions, read our How to Apply Polyurethane Countertop Sealer Guide.