The metal seal is the closure that fixes the two ends of the plastic strapping once tensioned, and the choice between a PP seal and a PET seal is not trivial: applying the wrong one tears the band or produces a seal that slips under real load during transit. This comparison of the two Fortemo seals helps you decide which one matches the strapping material you use in your operation.
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What to consider before choosing
Before buying, assess these four criteria. They determine whether the closure will withstand the full shipping cycle or produce loose pallets mid-transit.
- Strapping material in use: PP strapping has a soft surface and requires a seal with a smooth interior calibrated for that hardness; PET strapping has a rigid surface and requires a seal with serrated interior teeth that bite the band. Applying a PP seal on PET produces slippage under tension; applying a PET seal on PP tears the band.
- Strapping width and tensioner compatibility: both Fortemo seals are dimensioned for 13-16 mm (1/2 - 5/8 in) strapping, the standard palletizing widths in Dominican logistics. Always verify that the bite of the sealing tensioner matches the seal before proceeding with serial closures.
- Operation volume: the box of 1000 PP seals covers continuous-flow palletizing operations; the box of 600 PET seals responds to the lower volume typical of heavy strapping, where each pallet weighs more and fewer are closed per shift. Calibrate the purchase to the actual pace of pallets closed per day.
- Galvanizing quality: a seal with poor galvanizing rusts within a few weeks in the Caribbean climate and can stain adjacent product or reduce the mechanical integrity of the closure. Fortemo works with uniform galvanizing that keeps the seal operational throughout the full shipping cycle even in open-air transit.
PP strapping seal: smooth closure for polypropylene
- Smooth interior calibrated for the softness of PP strapping
- Uniform galvanized steel that resists Caribbean humidity
- Compatible with standard sealing tensioners for 13-16 mm
- Box of 1000 seals for continuous palletizing flow
- Permanent, flat closure with no sharp edges
- Not suitable for PET strapping (slips under high tension)
- Compatibility limited to 13-16 mm widths
Galvanized metal seal for polypropylene (PP) strapping 13-16 mm (1/2 - 5/8 in) wide, in a box of 1000 units. Smooth interior calibrated for the specific hardness of PP, where the serrated teeth of the PET seal would be counterproductive. Designed for warehouses, hardware stores, retailers and palletizing operations where PP strapping is the dominant format: palletizing corrugated cardboard boxes, closing bundles in daily flow, grouping light pipe and sealing regional export boxes.
PET strapping seal: serrated closure for polyester
- Serrated interior teeth that bite the rigid surface of PET
- High-strength galvanized steel for prolonged transit
- Compatible with standard sealing tensioners for 13-16 mm
- Box of 600 seals calibrated for heavy strapping volume
- Permanent closure with no slippage under real high tension
- Not suitable for PP strapping (the teeth tear the polypropylene)
- Higher unit cost than the smooth PP seal
Serrated metal seal (serrated seal) for polyester (PET) strapping 13-16 mm (1/2 - 5/8 in) wide, in a box of 600 units. Serrated interior teeth calibrated to bite the smooth, rigid surface of PET, maximizing friction to prevent slippage under the real tension of polyester. Designed for palletizing heavy materials (bricks, blocks, grouped bags), sealing wood loads and metal profiles for inter-island export, and agribusiness operations with dense bags palletized in PET.
Comparison table
| Feature | PP seal | PET seal |
|---|---|---|
| Compatible strapping material | PP | PET |
| Compatible widths | 13-16 mm (1/2 - 5/8 in) | 13-16 mm (1/2 - 5/8 in) |
| Interior | Smooth | Serrated teeth |
| Material | Galvanized steel | Galvanized steel |
| Packaging | Box of 1000 seals | Box of 600 seals |
| Brand | Fortemo | Fortemo |
| Compatibility with standard tensioners | Yes | Yes |
Use case → recommended product matrix
| If your case is… | Recommended product |
|---|---|
| Palletizing cardboard boxes with PP strapping in a logistics warehouse | → PP seal |
| Closing light parcel bundles with plastic strapping | → PP seal |
| Sealing bundles in a hardware store with polypropylene strapping | → PP seal |
| Grouping plastic pipe or light profiles in a workshop | → PP seal |
| Sealing regional export boxes with PP strapping | → PP seal |
| Closing a pallet of bricks or blocks with PET strapping for construction | → PET seal |
| Sealing a wood load or metal profiles with PET strapping | → PET seal |
| Closing agribusiness pallets with dense bags in PET | → PET seal |
| Inter-island export with heavy polyester strapping | → PET seal |
| Closing bulky packages where the smooth seal slips | → PET seal |
Before buying, define two facts: the strapping material you use (PP or PET) and the bite of your sealing tensioner. The practical rule: PP plastic strapping → smooth PP seal; heavy PET strapping → serrated PET seal. Mixing materials does not work — the PP seal on PET slips, and the PET seal on PP tears the polypropylene. If your operation handles both materials, consider keeping one box of each type clearly differentiated.
Do not use PP seals on PET strapping. The smooth interior cannot hold the high tension of polyester, which produces seals that slip as soon as the load suffers vibration or braking in transport. The consequence is a pallet that arrives loose or open at its destination, with the risk of damage associated with loose product. The investment in the correct seal is recovered on the first load that arrives intact.
All products compared
Does your case not quite fit the profiles described?
If you need to validate the choice for a specific operation or have a combination that this comparison does not exactly cover, you can ask about it here.
Frequently asked questions
Why does a PET seal not work on PP strapping?
The PET seal has serrated interior teeth calibrated to bite the rigid surface of polyester. On PP strapping (softer), those teeth tear the band at the closure point, which reduces the strength of the strapping right where it is needed most. For PP, always use the smooth seal.
Are Fortemo sealing tensioners compatible with both seals?
Yes, as long as the width is 13-16 mm (1/2 - 5/8 in). Verify that the bite of your tensioner matches the geometry of the seal in use before serial closures. Fortemo tensioners for PP and PET strapping respect the width standard shared by both seals.
How many seals do I need per typical pallet?
It depends on the strapping scheme. A pallet with two horizontal turns needs two seals; with cross strapping (two horizontal + two vertical) it needs four. Calculate the average daily consumption and buy the full box to avoid running out of material mid-shift.
