Kitchens – use silicone “window & door” caulk between a kitchen counter and backsplash

Cutting the countertop to length:

Try making a custom circular saw jig to cut your countertop to size. 3/4" plywood placed together at right angles with a cleat for guiding your saw should give you a straight cut. Assemble the jig with extra material, then cut it to size with your saw for a perfect fit.

Use a saw blade with a high tooth count and cut the counter upside down. That way, the blade teeth are traveling down (but really up) into the counter surface, minimizing chances for chipping out. Start by cutting the backsplash first, with the rest of the counter pointing towards the floor. Then stop and rotate the countertop so it's upside down and finish the cut. Be sure to support the cutoff material so it doesn't break off a chunk of the laminate near the end of the cut.

As @auujay points out, masking tape can also help reduce the likelihood of chipping.

Source: woodworkingtips.com

Cutting the sink hole:

I crawled several forums looking for advice on this one. Some suggested techniques (in the order that I would try them) were:

• Use a jigsaw with a down-stroke blade to cut out the sink hole. By cutting on the top surface, you have a more accurate picture where your sink hole will be, and the downstroke blade will eliminate chip-out. Start each rounded corner with a 1/2" spade bit.
• Use a jigsaw with a metal cutting upstroke blade. The finer teeth will make for slower work, but have less of a chance of chipping.
• Use a circular saw to cut straight sides from underneath the countertop. Flip over and finish the rounded corners with a downstroke jigsaw blade.

Once again, use masking tape for both cut line visibility and to reduce the chance of chipping the laminate. Also remember to support the cutout section to avoid tearing the laminate near the end of the cut.

Ok Aaron, you will need to remove as much of the old caulk using a sharp putty knife. If you are careful you will not scratch the block or tile, however it can be tricky. Alternately, a rigid plastic scraper or caulk removal tool (cheap at HI stores) can be used to assure no scratching or gouging. The next step is to run a line of 3M delicate surface painter's tape in a very straight line down the counter top and along the back splash exactly where you want the caulk to end. Select a 100% silicone caulking of the color you want. Apply an even bead of caulk to the seam, smooth it with your finger or a plastic tool tapering the edge thinly at the edge of the tape. Work quickly, do not let the caulking start to set up. As soon as you are happy with the bead's smoothness, remove the tape immediately. Let the caulk set up and cure for 24 hours before exposing it to water. Good luck.