What Do I Use to Fill in Joints of Counter Tops?

Flowing Grade Polyester

• Use flowing grade polyester to fill in countertop joints. Flowing grade polyester is a thick synthetic liquid that pours easily and dries quickly. Its hard, durable composition makes it a strong filler for countertop joints. According to Stone World, you may need to use a seam setter or seam separating tools to open the joint slightly so the liquid polyester sufficiently fills the seam. Flowing grade polyester is usually clear or transparent, so there is no need to tint the polyester for white or light-colored countertops.

Tinted Polyester

• Add tint to your flowing grade polyester to blend with colored or dark countertops. Purchase polyester tinting and follow the directions to determine the amount of pigment needed to match your countertops. Flowing grade polyester is available in metal cans, similar to small paint cans, so adding and stirring the tinted mixture is quick and convenient. Avoid adding too much pigment or your countertop joints will stand out, like an outlined surface, against your countertops.

Application Process

• Install a seam setter, the tool that holds and slightly separates your countertop sections, and apply liquid grade polyester to your countertop joints. Allow the polyester adhesive to flow up over the top of your countertop. Stone World says it takes practice to determine the necessary amount of liquid polyester, but you should not remove the seam setter or clean the excess polyester from your countertop until it has dried. Avoid filling the joint to a level below the surface of your countertop, or food particles could get trapped in the joint.

Smooth Finish

• Shave the dried, excess liquid polyester off your countertop with a box cutter or razor blade. Stone World states that holding a razor blade straight up and perpendicular to the face of the stone is critical. If the blade gets beneath the surface of the polyester glue, it likely will pull the dried adhesive up and out of the joint. After the dried polyester is scraped away, rub a pumice stone across the seam to smooth the joint. Saturate a rag with denatured alcohol and wipe it over the joint's surface to remove excess scrapings and restore the color of the polyester.