Steel strapping is the one band that will destroy a light protector on the first tensioning cycle. It has almost no stretch, it is closed with a metal seal, and it is applied at tensions that a paper profile has to resist without crushing. Specifying for steel means going up in wall and paying attention to the seal, not the corner.
Specification at a glance
| Band width | Minimum leg | Wall | Extra |
|---|
| 19 mm | 40 mm | 4 mm | Seal piece 100 mm |
| 32 mm | 50 mm | 4.5 mm | Seal piece 120 mm |
| 40 mm | 60 mm | 5 mm | Base doubled 200 mm |
| 50 mm and above | 70 mm | 5 mm, doubled | Powered tension, both faces |
Three failure points, in order of frequency
The seal. A crimped steel seal has burred edges that bear on a narrow line. If the protector is thin, the seal cuts through it and the band then cuts the carton. A short second piece under the seal, 100-150 mm long and one wall grade up, removes most of this.
The corner radius. Steel band does not conform. On a sharp carton corner it bridges the corner and bears on two edges, so the protector is loaded on two lines at once and folds along the crease. A protector with a slightly wider leg spreads those two lines apart.
Band alignment. A steel band that is not square to the edge walks off a narrow protector during transit. Leg width at least 10 mm wider than the band on each side is the practical rule.
Wall build for tonnage
Up to about 2 tonnes we quote a 4 mm wall with 50 mm legs. Between 2 and 5 tonnes the wall goes to 5 mm and the leg to 60 mm. Above 5 tonnes, or where the band is tensioned with a powered tool, the base 200 mm is doubled and the band line gets a second short piece.
These are starting points, not guarantees. The load-bearing question is always how much the pack can compress, and that is a property of the pack, not of the protector.
Steel band on timber, steel and paper packs
On a timber crate the band bites into the wood and holds. On an all-paper pack the band creeps and the load settles; here the protector does the work that the wood would have done. On steel sections the band is protecting a hard edge and the protector mainly prevents the band from sliding and scratching.
Questions buyers ask before ordering
Will a paper protector hold a steel band?
Yes, if the wall is matched to the band and the seal is protected. A 2.5 mm board under a steel band is not a specification, it is a cut corner.
Can I use PET protectors instead?
Plastic edge protectors resist the seal better but cost more and are a separate waste stream. For one-way export paper is usually the better trade.
Do I need protectors on all four corners?
Yes, and on both faces where the band runs around a pack. Bands are usually applied in pairs, so count each pair as two protectors.
What if the band is already cutting the carton?
Go up one wall grade and add the seal piece. If the carton itself is collapsing, the pack is under-specified and no protector will fix it.
Can protectors be cut to the exact crate height?
Yes, to the millimetre, and bundles are labelled by length so mixed orders stay separate.
To compare profiles, send a photo of a packed pallet and the band tension you use to mona@hengnicepacking.com.
