Heavy duty is a genuine grade, not a marketing word: it means a 6-8 mm laminated wall with 60-100 mm legs, used under steel banding, on dense loads and on loads that will be double stacked. It is also the point where paper stops being the right answer for some jobs, and saying so is part of specifying it honestly.
Heavy duty grade data
| Duty | Wall | Leg | Use |
|---|
| Standard | 3 mm | 40-50 mm | Cartons, light pallets |
| Medium | 4-5 mm | 50-60 mm | Export pallets, panels |
| Heavy | 6 mm | 60-70 mm | Dense loads, double stack |
| Extra heavy | 8 mm | 80-100 mm | Steel, out of gauge |
| Beyond paper | Two profiles or timber | n/a | Cradles and structural blocking |
What heavy duty buys
A 6-8 mm wall resists the notch that a steel band or a sharp edge would make in a thin board, and it carries compression without folding at the crease. With 60-100 mm legs it also spreads load far enough that a dense panel or a machine foot does not mark.
The gain is not linear. Going from 3 mm to 5 mm removes most band cutting; going from 6 mm to 8 mm adds margin for stacking rather than solving a new problem. Buy the margin where the load is stacked high or the route is long, not by default.
Two boards instead of one very heavy board
Above 8 mm the board becomes hard to fold tightly and the fold radius starts to bridge the corner, so the profile rocks instead of sitting flat. At that point two 5 mm profiles fitted back to back, or one profile plus a flat pad under the band, performs better than a single heavy section.
This is also the cheaper route in many cases, because two standard profiles are made from stock board while an 8 mm custom section is a dedicated run.
Where paper should give way
Structural blocking, machine cradles and loads over several tonnes on a single contact point are jobs for timber or steel, with paper as the interface layer rather than the structure. A supplier who sells a paper board as a load-bearing member is setting up a failure.
Weather is the other limit. A soaked heavy duty board behaves worse than a dry standard one, so deck stowage needs a coated face or a different material altogether.
Questions buyers ask before ordering
What wall counts as heavy duty?
6 mm and above, with legs of 60 mm or more. Below that it is a standard or medium grade.
Is 8 mm better than two 4 mm boards?
Usually not. Two boards conform better and cost less, because 8 mm is a dedicated run.
Can heavy duty board replace timber blocking?
No. It is an interface and protection layer, not a structural member.
What about a wet route?
Specify a coated face, or use a different material. A soaked board loses the properties you paid for.
What is the minimum order?
3,000 meters, and heavy grades are usually run to order rather than stocked.
To compare profiles, send a photo of a packed pallet and the band tension you use to mona@hengnicepacking.com.
