A scratch on glass can sometimes be polished out. A chipped edge cannot. The edge is where the sheet is weakest and where every impact in transit is delivered, which is why glass edge protectors are specified on the edge and not on the face — and why the choice of material at that interface decides whether a pack arrives intact.
What actually breaks a sheet in transit
Not weight, in most cases. Three mechanisms account for nearly all breakage. The first is edge impact: the sheet lands on a corner during loading. The second is bending under its own weight when a pack is carried at the ends rather than supported underneath. The third is a point load — a strap, a band, or a rough pallet deck pressing on one spot through the pack. Edge protection addresses the first and the third; the second is a handling and A-frame question.
Where the board sits on an A-frame
On an A-frame or stillage, the sheet rests on its bottom edge at an angle. That bottom contact line carries the entire weight of the pack, so it needs continuous protection rather than a corner piece. The L profile runs the full width of the sheet at the base, and a second pair runs down the two vertical edges to take the knocks during loading. Boards fitted only at the corners leave the middle of the bottom edge bearing directly on the frame.
Paper against foam against timber
Foam absorbs impact but does not spread load, and it compresses permanently under a strap. Timber spreads load but adds weight, splinters, and in many export markets brings phytosanitary requirements. Paper does both jobs to a moderate degree: a 4-5 mm laminated L profile spreads strap load and takes a knock without transferring it, weighs almost nothing, and needs no treatment certificate. The limitation is water — paper that gets wet stops protecting anything.
The moisture question
Glass packs in a container see condensation cycles that paper does not like. Two practical measures: keep the board moisture content below 10 percent at dispatch, and avoid direct contact between wet packaging and the glass surface for long periods, because a damp kraft board pressed against glass for weeks can leave a haze that has to be polished. Where a pack is known to travel through humid routes, specify a moisture-resistant coating or a white-top facing.
Sizing for the sheet thickness
A 6 mm sheet is protected adequately by a 3 mm wall with a 25-30 mm leg. A 10-12 mm sheet needs 4 mm and a 40 mm leg, because the leg has to bridge the thickness and still sit flat on both faces. Above 19 mm — laminated or toughened architectural glass — go to 5 mm and a 50 mm leg, and expect the pack weight, not the board, to dictate the pallet design.
Loading sequence that protects the edges
Fit the base board before the first sheet goes on, so the bottom edge never touches the frame. Load the pack with sheets vertical and slightly inclined, not flat. Fit the vertical edge boards before banding. Band over the paper, never directly on the glass. Then wrap, and mark the pack as glass on all four sides rather than one.
Questions buyers ask
Will a paper board stop a sheet breaking if the pack is dropped? No. It reduces edge damage and point load damage. A drop is a handling failure, not a packaging one.
Can the board be cut to the exact sheet width? Yes, to the millimetre from 300 mm to 6,000 mm, which matters when the board must sit flush to the frame.
Does the board mark the glass? Dry board, smooth facing, no marking. Damp recycled board under pressure can leave a haze.
Is there a grade for very humid routes? Yes, a moisture-resistant coating or a white-top facing; both are made to order.
What is the minimum order? 3,000 metres per size, which is roughly 1,500 boards at a 2,000 mm cut.
Send the sheet thickness, the pack dimensions and the frame type, and we will specify the board and the fitting sequence. Email mona@hengnicepacking.com.
