A mirror has one vulnerability a glass sheet does not: the silvering runs to the edge, and any moisture or abrasion at that edge shows as a dark line that spreads. Edge protection for mirrors is therefore as much about keeping the edge dry and untouched as about stopping a chip.
The edge is where a mirror fails first
The reflective layer is protected by paint on the back and by the frame on the front, but the cut edge is exposed. Water at that edge creeps under the coating and the black edge creep that follows cannot be reversed.
A paper U channel covers the edge and both faces for a few millimetres. It does not seal the mirror, but it stops direct contact with a damp pallet, with another mirror, and with hands.
Specification at a glance
Mirrors are usually 4-6 mm, so the channel is narrow with a short leg. The critical property is that the board is dry and clean, not that it is thick.
| Mirror | Inner width | Leg | Note |
|---|
| 4 mm mirror | 4-5 mm | 25 mm | Short leg, dry board |
| 6 mm mirror | 6-7 mm | 25-30 mm | A-frame packing |
| Bevel-edged mirror | 6-7 mm | 30 mm | Bevel needs a wider inner |
| Bundle, long edges | 6 mm | 25 mm | Interleave between sheets |
| Single in a crate | 6 mm | 30 mm | All four edges plus corners |
A-frames, crates and single pieces
In an A-frame, mirrors lean and the edge takes a shear load along the channel. A short leg is better here because a long leg bridges across the frame and creases.
For a single mirror shipped in a crate, the channel goes on all four edges plus corner protection at the frame contact. For a bundle, the channel goes on the two long edges and the mirrors are separated by interleaving sheets.
Moisture control that actually matters
The most common cause of edge creep on an exported mirror is a pack that was closed with damp paper inside. Keep the channels in their bundle wrap until the moment of fitting, and do not store them on a concrete floor.
Where the route is long, discuss a coated facing. It slows moisture take-up but does not make the pack waterproof, and the crate ventilation still does most of the work.
Questions buyers ask before ordering
Will the channel stop black edge creep?
It stops contact with moisture and abrasion, which are the usual causes. It is not a seal, so a damp pack can still cause it.
What inner width for a 6 mm mirror?
6-7 mm, so the mirror slides in without forcing the fold.
Can I use the same channel for glass and mirror?
Yes, but for mirror the dryness of the board matters more than the thickness.
Do you supply corner protection as well?
Yes, paper corner profiles from the same board, which is usual for a mirror crate.
Is a coated board worth it for export?
It slows moisture take-up on a long route. Ask for it to be quoted alongside the standard board.
Tell us the piece size, quantity per shipment and how it is handled at mona@hengnicepacking.com and we will advise on the board build.
