Corian countertops are high end kitchen and bathroom counters and sink-tops made by the large DuPont company. These countertops are non-porous and created from a variety of plastic resins. While some complete sink or counter fixtures may come with predrilled holes for installing water lines and faucets, countertop slabs of Corian may come with no such holes.
Obviously you’ll need to drill holes into the countertop to install a fixture, faucet, or water filter line. You can do this yourself and save money. But keep in mind that you can easily damage expensive Corian countertops if you are not careful. Be sure you are comfortable using power tools and have a very steady hand before trying to drill your own countertop holes.
To begin, measure where the holes need to be drilled. You can determine this by measuring the diameter of the tube or pipe that needs to fit through each hole. You’ll want to make sure the hole is smaller than the diameter of the faucet or fixture connecting to the hole. For example the hole for a faucet pipe should be big enough for the pipe to fit but small enough so the faucet base conceals the hole.
Place a chalk line just above the hole spot and just below it. Place a small strip of masking tape over each spot where a hole is needed The chalk lines should be visible. The tape will protect the surrounding Corian surface from scratches and debris. Use chalk to draw a line over the tape to connect to the parallel chalk lines. Mark the exact center of this third line with a small X where the drill bit will be placed.
Use a spiral drill bit with a power drill to start a small hole in the center of the marked X. Drill all the way through the counter until the bit comes out on the underside.
Connect a router or hole-saw attachment to the drill bit and carefully position it directly over the starter hole. The starter hole made with the first drill bit should be in the center.
Start up the drill bit and get it up to about medium speed setting. Usually holding the drill trigger in about halfway will do this. You don’t want to drill running at full speed. With the drill running at medium speed push it against the Corian surface with the starter hole in the center.
Press down on the drill gently with your other hand while drilling the larger hole. Make sure the drill, bit, and router attachment are straight and the tip is hitting the countertop surface evening. Move slowly through the countertop in a fluid motion. Do not under any circumstances jerk the drill, pull it out quickly, or let go of the drill trigger.
When you have gone all the way through the Corian surface, with the drill still running carefully and slowly pull it straight up and out. Repeat for additional holes as needed. Keep in mind you might need different size hole or router bit attachments for each hole based on diameter.
Remove the masking tape and sand down the hole edges with medium grit paper until smooth. Install the faucets or water lines as indicated in the install manual provided with the item.