Glass or tile bits are shaped to reduce the risk of shattering brittle materials. These should be carbide-tipped. Diamond bits are more expensive, but can drill through extra-hard tiles. You may need these for modern porcelain tiles (made since the late 1990s), because they’re much harder than ceramic tiles. [2] X Research source Masonry bits are made from carbide-tipped steel. These are strong enough to drill through, but their shape increases the risk of shattering porcelain and other brittle tiles. As a last resort, use high speed steel (HSS) bits. Expect these to wear down after one or two holes. [3] X Research source If drilling a large hole for plumbing installation, use a hole saw bit made from one of the above materials. Make sure its central pilot bit is also made from a suitable material.

If you’re using a solid drill bit larger than 1⁄4 inch (0. 6 cm), consider drilling a pilot hole with a smaller bit first.

Applying too much pressure can cause the tile to blow out and crack on the backside, creating a weak spot in the tile and often a much larger hole than originally intended. Diamond bits are especially vulnerable to damage from fast drilling. Drill no faster than 600 rpm for diamond bits below ½ inch (1. 25 cm), or 450 rpm for bits from ½ to 1 inch (1. 25—2. 5 cm). [6] X Research source

“Pump” the drill every 15 to 20 seconds with a tiny up-and-down motion. This draws water to the tip of the bit, where friction is greatest. [7] X Research source The drill bit should never feel more than slightly warm. If it gets hot, stop and wet it until it cools down. You can also dip the drill bit into a little water periodically to keep it wet. [8] X Expert Source Art FrickeHome Renovation & Repair Specialist Expert Interview. 1 July 2020. As an alternative, lubricate the drill with drilling oil.

Take care not to get the epoxy in the grout lines between tiles.

Before filling, mix the epoxy with epoxy tint the same color as the tile. Or, after filling, paint over the repair using an oil-based enamel paint marker.

Note the thickness of the tile as well. A thinner replacement will need a layer of mastic to raise it. [11] X Research source

Wear gloves and safety glasses. Lay down cloth to protect surrounding surfaces from ceramic shards.

Follow label instructions for mixing the mortar. You may need to wear a dust mask.