How do you cut marble countertops in place?

Cutting marble countertops in place can be a tricky process, but with the right tools and techniques, it can be done successfully. Here is a step-by-step guide on how to cut marble countertops that are already installed.

Determine the Cut Location

First, you need to decide where you want to make the cut. Use a pencil to mark the cut line on the countertop. Make sure you measure carefully so the cut is straight. For odd-shaped cuts like cutouts for sinks, trace the shape onto the marble.

Protect the Surrounding Area

Cover the floor around the countertop with rosin paper or a drop cloth to catch any marble dust or debris. You may also want to tape plastic sheeting along the walls. Marble cutting is very messy, so take steps to protect nearby surfaces.

Equipment Needed

Cutting marble requires specialized power tools and blades:

• Wet saw with a diamond blade designed for cutting marble or stone
• Angle grinder with a diamond blade (for tight corners or tricky angles)
• Silicone carbide sanding pads (for smoothing cut edges)
• Water source and bucket
• Safety gear like goggles, ear protection, gloves, and a face mask

Score the Marble

Use the angle grinder to score the marble lightly along the cut line. This helps guide the wet saw blade. Don’t try to cut all the way through with the angle grinder – it is only used for scoring. Press firmly but let the diamond blade do the work.

Cut with the Wet Saw

With a wet saw, marble must be cut very slowly to avoid cracking. Work in sections for long cuts.

Steps for using a wet saw on countertops:

1. Set the marble slab on the wet saw’s tray. Position it so the cut line aligns with the blade.
2. Adjust the tray height so the blade penetration is about 1/4 inch deep into the marble.
3. Turn on the water feed to keep the marble cool during cutting.
4. Turn on the saw and slowly guide the spinning blade along the cut line. Apply steady, even pressure but don’t force the blade.
5. Lift the cut piece free and turn off the saw to inspect the cut. Repeat as needed to complete long cuts.

Smooth the Edges

Once cut, use a silicone carbide sanding pad to smooth and polish the sharp edges of the marble. Work your way from coarser to finer grit sanding pads for the best finish.

Seal the Marble

Apply a penetrating marble sealer to all cut edges and surfaces. This prevents moisture damage and staining. Allow the sealer to dry completely before using the countertop.

Clean Up

Thoroughly clean the area to remove all marble dust and debris. Vacuum first then mop the floors. Dispose of plastic sheeting and rosin paper properly.

Conclusion

Cutting marble countertops in place takes patience and the right tools, but it can be done DIY-style. Just be sure to work slowly and take safety precautions when cutting. Plan the cuts carefully and allow time for drying sealers before using the countertop. With care, your custom cut marble will last for many years of beauty and enjoyment.