Every coil is protected at the same place: where the band turns over the coil lip. On a curved surface the band contacts a very short arc, so the pressure there is higher than on a flat corner, and the protector has to follow the curve without creasing. That is why coil profiles are specified by wall and by how well the board bends, not by leg width alone.
Profile data for coils
| Coil | Wall | Fit |
|---|
| Steel, eye to sky | 4-5 mm | On the outer wrap, under the band |
| Steel, eye to wall | 5 mm doubled | On both end faces at the cradle |
| Aluminium | 3-4 mm, clean dry | Coated face on bright surface |
| Wire coil | 4 mm doubled at tie | Tie point only |
| Paper or board coil | 3 mm | Ring or curved board |
Curved contact changes the specification
On a flat corner the band touches along a line and the board spreads it across the leg. On a coil lip the band touches a short arc and the curvature means the board is bending while it is loaded. A stiff board will bridge the curve and bear on two points instead of following it.
The practical fix is a thinner, more flexible board doubled at the contact, rather than a single thick board that will not conform. For a tight coil radius this matters more than an extra millimetre of wall.
Steel, aluminium, wire and paper
Steel coil is the heaviest case and is quoted separately with a 4-5 mm wall. Aluminium is softer and marks more easily, so the board has to be clean and dry, and a coated face is used where the surface is bright.
Wire coil is springy: it expands against the band, so the band tension rises after packing. Protection here is about keeping the band from cutting the coil tie, and a doubled board at the tie point is common.
Paper and board coils are the lightest case and the specification is driven by print quality rather than strength.
Eye to sky or eye to wall
An eye to sky coil sits on its end, so the band crosses the outer wrap horizontally and the board sits on the wrap, not on the coil face. An eye to wall coil rests on its outer surface, so the band crosses the two end faces and the board has to protect the coil edge where it meets the cradle.
Getting this wrong is the most common coil protection mistake: the board is fitted to the wrong face and the band still bears on bare metal.
Questions buyers ask before ordering
How do I know which face to protect?
Check how the coil sits. Eye to sky means the band crosses the outer wrap; eye to wall means it crosses the end faces.
Will a thick board conform to a tight coil?
Not always. Below a certain radius a thinner doubled board follows the curve better than a single thick one.
Do you supply coil edge protectors with adhesive?
No. The band holds them, and adhesive would slow the packing line.
Can the protector be printed with the coil number?
Yes, one or two colours, which helps with traceability.
What about moisture between board and coil?
Keep boards dry. A damp board against bright aluminium is a staining risk.
Quote requests with cut length and quantity reach us at mona@hengnicepacking.com and are answered within one working day.
