Gluing and Sealing a Mirror

Which product adheres a mirror to a painted bathroom wall and seals around the edge?

Selleys Liquid Nails Mirror & Metal is ideal for this job. It is a premium grade, high strength construction adhesive that delivers strong bonds on mirrors, metal and glass, and it will not discolour mirrors — which is the property that rules out most general adhesives on this application.

You can also use Mirror & Metal to seal around the edges of the mirror once it has fully cured behind the mirror. Allow the adhesive to fully cure for about 7 days before sealing around the edges. If you want a different colour around the edge, use Selleys Wet Area Silicone or Roof & Gutter Silicone instead.

Why you must wait a week before sealing the edge

This is the single most important instruction on the page, and the reason is not impatience — it is chemistry.

Mirror & Metal is a neutral cure silicone that cures at 2 mm per day, drawing moisture from the air. Behind a mirror, the only path for that air is the gap around the perimeter and between the adhesive strips. Seal that perimeter on day one and you have closed the only route by which the adhesive behind the glass can cure. It will stay soft, sometimes for months.

The manufacturer's own instruction is explicit: do not seal around the edges of the mirror for at least a week to allow air circulation. The seven-day figure follows from the cure rate — a bead of practical thickness takes several days to cure right through, and a week gives it margin.

The same reasoning drives the strip pattern. Apply strips or beads of adhesive approximately 8 cm apart, and when the mirror is pressed onto the wall the strips must not spread into or touch one another — a gap must remain between them. Those gaps are the air channels. Do not apply the adhesive as blobs or dollops.

Working figures

Property	Liquid Nails Mirror & Metal
Technology	Neutral cure silicone
Colour	Translucent
Skin time	10–15 minutes (weather dependent)
Tack free time	45 minutes
Cure time	2 mm/day
Support mirror for	Normally 72 hours
Do not seal edges for	At least a week
Temperature resistance	−60°C to 150°C, high UV resistance
Packaging	310 g cartridge

Indicative data only, not intended for the preparation of specifications.

The painted wall condition

Your wall is painted, and that is not incidental — it is a requirement. Mirrors should not be fixed directly to unpainted timber, plaster, concrete or brick walls. These surfaces should be painted to prevent potential damage to mirrors. Raw masonry and plaster are alkaline and hold moisture, and both attack the silvered backing of a mirror from behind.

Two conditions apply to the paint itself:

• Painted surfaces should not be flaky or peeling. The adhesive will hold the paint, and the paint will hold the mirror. If the paint is loose, that is the weak link in a job where the failure mode is a sheet of glass coming off a bathroom wall.
• Freshly painted surfaces should be allowed to dry for at least 7 days before the job is done, and compatibility should be tested on painted surfaces before use.

How to fix and seal the mirror

1. Check the wall: painted, sound, not flaky or peeling, and at least 7 days since painting.
2. Ensure the surface is sound, dry and free from oil, grease and dust.
3. Cut the cartridge, fit the nozzle and cut it to size — approximately 5 mm. Apply with a caulking gun.
4. For mirrors up to 6 mm thick, apply strips or beads of adhesive approximately 8 cm apart. Do not apply as blobs or dollops, do not apply over vinyl backing, and stay at least 5 cm in from the mirror's edge — adhesive near the edge can affect performance or cause discolouration.
5. For vinyl-backed mirrors, apply the adhesive inside the vinyl cut-outs and not over the vinyl.
6. Place the mirror against the wall immediately after applying the adhesive, before it skins — within 5 minutes.
7. Press it on so the strips spread, but check that they do not spread into or touch one another. A gap must remain between them.
8. Support the mirror with clips or tape until the adhesive develops strength, normally 72 hours.
9. Leave the edges open for at least a week.
10. Only then seal around the perimeter — with Mirror & Metal itself, or with Wet Area Silicone or Roof & Gutter Silicone if you want a different colour.

Choosing the edge sealant

All three options are neutral cure, which is what you want at a mirror edge — neutral cure products do not release acetic acid as they cure and so will not damage the mirror's silvered backing.

Mirror & Metal is translucent, so it disappears against most tiles. Wet Area Silicone is the wet-area product, non-corrosive, curing at 2 mm per 24 hours with a skin time of 5 to 10 minutes; it needs 72 hours to fully cure before exposure to continuous water. Roof & Gutter Silicone comes in the widest colour range, including a set of Colorbond-matched colours, and is worth considering only if you want a specific colour — note that it is not paintable.

If you want the joint between the mirror edge and the surrounding tiles covered in more depth, see silicone between mirror and tiles.

Limitations

• Do not fix mirrors directly to unpainted timber, plaster, concrete or brick.
• Do not apply adhesive within 5 cm of the mirror's edge, or over vinyl backing.
• Do not seal the perimeter for at least a week.
• Glue lines may be visible through surfaces that are not perfectly opaque — relevant on thin or decorative mirrors.
• Test compatibility on painted surfaces before using.
• Wet Area Silicone is listed for non-oily timber among its substrates; oiled timber should be tested first.
• Roof & Gutter Silicone is not paintable, and paint must be allowed to dry for at least 7 days before applying it on top.

Clean up

Uncured product removes with mineral turps. Cured product can be removed with Selleys Sealant Remover or by mechanical action — which is not something you want to be doing on the face of a mirror, so clean squeeze-out while it is wet.

Common questions about gluing and sealing a mirror

Can I seal the edges straight away?

No. Allow about 7 days for the adhesive behind the mirror to fully cure first. Sealing early cuts off the air the adhesive needs.

How long do I hold the mirror up?

Support it with clips or tape until the adhesive develops strength, normally 72 hours.

Will the adhesive damage the mirror backing?

Mirror & Metal is a neutral cure silicone with superior adhesion for mirrors, and it will not discolour mirrors. Keep it at least 5 cm in from the edge and off any vinyl backing.

How should I apply the adhesive?

In strips or beads about 8 cm apart for mirrors up to 6 mm thick, never as blobs or dollops, with gaps left between the strips.

Can I fix a mirror to bare plaster or brick?

No. Those surfaces should be painted first to prevent potential damage to the mirror.

What if the wall was painted last week?

Freshly painted surfaces should dry for at least 7 days before the job. Test compatibility on the paint before you start.

Can I use a different colour around the edge?

Yes — Selleys Wet Area Silicone or Roof & Gutter Silicone. Both are neutral cure.

Is it suitable for a steamy bathroom?

Mirror & Metal is heat and steam resistant, with a temperature range of −60°C to 150°C and high UV resistance, suitable for inside and outside the home.

What size cartridge do I need?

310 g. One cartridge covers a typical bathroom mirror with strips at 8 cm spacing.

How do I clean up excess?

Mineral turps before it cures. Once cured, use Selleys Sealant Remover or mechanical action.