Material guide
Glass & mirror
What works on glass and mirror: the right drill bit and speed, how to score and snap, which glue holds, and why you never cut tempered glass.
Quick facts
- Check first
- Tempered glass can't be cut or drilled. It's marked in a corner. If you can't find the mark, don't drill.
- Best drill bit
- Diamond hole saw or core bit, always wet. Carbide spear-tip glass and tile bits for small holes.
- Drill speed (diamond)
- 1/8 to 1/2 in: 1,000 to 2,400 rpm. 5/8 to 1-1/2 in: 1,000 to 1,250 rpm. Light pressure.
- Best cutter
- Carbide-wheel glass cutter: one even score, then snap. Never go over a score twice.
- Best glue
- Glass glue (a super glue made for glass). Loctite's is indoor only, rated to 180°F (82°C).
- Hanging a mirror
- Mirror mastic plus clips. The mastic maker calls for clips on every mirror.
Glass is hard and smooth, but it's brittle. It doesn't bend before it breaks. A small chip or a hot spot can turn into a crack that runs across the whole sheet.
That's why glass needs different tools. You don't saw it or drill it like wood. You score it and snap it, or you grind it slowly with diamond and water. Water keeps the glass cool and washes away the glass dust.
First, find out what kind of glass you have. Plain window and picture glass is annealed, and you can cut and drill it. Tempered glass is much stronger, but it can't be cut or drilled at all. Touch it with a bit and it bursts into small cubes. Tempered glass is marked with a small etched stamp in one corner.
Mirror is glass with a coating on the back. The coating is easy to scratch and can be damaged by the wrong adhesive, so treat the back side with care.
Drill into glass & mirror
Use a diamond hole saw or bit and keep it wet the whole time. Tape the spot, start at a 45° angle with small bits, then stand the drill up. Use light pressure, and ease off as you break through. Stay 1 in from any edge. Never drill tempered glass.
What to use: Diamond hole saw + a clay water dam
Guides
- How to drill through glass (bottles, shelves, mirrors) (coming)
- Can you drill tempered glass? (coming)
- What marker writes on tile, glass, and metal (and wipes off) (coming)
Cut glass & mirror
Clean the glass and lay it flat. Run a carbide-wheel cutter along a straightedge in one steady pass, off the edge. Then snap it over a straightedge or with running pliers. A gritty white line means too much pressure. Tempered glass can't be cut at all.
What to use: Oil-fed carbide-wheel cutter + running pliers
Guides
- How to cut glass and mirror at home (coming)
Glue glass & mirror
For glass to glass or glass to metal, use a glue made for glass on clean, dry, close-fitting parts. Loctite Glass Glue sets in 15 to 60 seconds and is dishwasher safe after one week. It doesn't fill gaps, and it's for indoor use only.
What to use: Glass glue for small clear repairs
Guides
- Does Gorilla Glue work on glass? (coming)
- Glue glass to glass (clear and dishwasher-safe options) (coming)
- Glue glass to metal: UV glue vs epoxy vs silicone (coming)
- How to remove super glue from glass, plastic, and skin (coming)
- Mounting tape vs glue on tile, glass, and painted walls (coming)
Screw or anchor into glass & mirror
Glass can't hold a screw. Hang a frameless mirror with clips on the wall that grip its edges, and add mirror mastic that is safe for the mirror backing. For a shelf or panel, use clamps or brackets made for glass, or a pre-drilled panel.
What to use: Mirror clips + mirror mastic
Guides
- Wall anchor types explained: which one for which wall and weight (coming)
- Adhesive hooks vs anchors: what actually holds on tile and painted drywall (coming)
Sand or finish glass & mirror
Take the sharp edge off with wet silicon carbide sandpaper on a block. Use light pressure and keep the paper wet so the glass stays cool and the dust stays down. Dress the rim of a drilled hole with fine paper too, so it's less likely to crack.
What to use: Wet-or-dry silicon carbide paper
Guides
- Sandpaper grit chart: which grit for which job (coming)
Safety basics
- Never drill or cut tempered glass. Check the corners for the stamp first. If you're not sure, don't risk it.
- Wear safety goggles and gloves. Cut edges are razor sharp, and chips fly when glass breaks.
- Keep water away from power. Use a cordless drill for wet drilling when you can. If the drill has a cord, plug it into a GFCI outlet.
- Clean up with care. Wet glass dust can scratch. Rinse it away instead of scrubbing.
Sources
- What is tempered glass? Glass can't be cut or drilled after tempering; dice break pattern (Bendheim)
- Drilling holes in aquariums with diamond hole saws: never tempered, corner etch, coolant, speed chart, 45° start, 1 in from edges, tape, fine sandpaper (Inland Craft)
- Glass & Tile Bits: carbide tip, for rotary drills, 2,000 rpm max marking (Bosch)
- Glass cutting basics: score once, even pressure, don't retrace a score, running pliers (Bullseye Glass)
- LOCTITE Glass Glue technical data sheet: glass to glass and metal, 180°F limit, indoor only, no gap filling, dishwasher after 1 week (Henkel)
- Heavy-bodied mirror mastic: mechanical fasteners such as mirror clips must be used for all mirror applications (C.R. Laurence)
- How to sand glass by hand: silicon carbide, wet sanding, light pressure, mask, glasses and gloves (Empire Abrasives)
- OSHA 29 CFR 1910.133: eye and face protection