You have just received a box of notched metallic seals for PET strapping and are going to use them to close heavy loads where a smooth seal no longer holds. The internal notching is the key technical feature of the PET seal: it bites into the rigid surface of the polyester and prevents the slippage that a conventional PP seal cannot prevent. This guide explains how to identify the correct seal, place it properly on the strap, and recognize a reliable closure under the actual tension of PET.
Product Specifications
Fortemo PET strapping seals are offered in boxes of 600 units, sized for 13 to 16 mm strapping. They are flat galvanized steel buckles with internal serrated notching—the feature that distinguishes them from PP seals. Here are the technical details:
| Specification | Value |
|---|---|
| SKU | 747451 |
| Material | High-strength galvanized steel |
| Compatible with strap widths | 13 to 16 mm (1/2 to 5/8 in) |
| Internal type | Serrated |
| Compatible strap material | Polyester (PET) |
| Packaging | Box of 600 seals |
| Sealing tool | Manual crimper for PET strapping |
| Brand | FORTEMO |
Step-by-step usage guide
The seal is not applied alone: it operates within the complete heavy-duty strapping cycle. The following procedure assumes that you have already wrapped the package with PET strapping and have the tensioner at hand to tension and the crimper to seal.
Place the seal over the two overlapping strap layers
When the two ends of the strap meet on the face of the package, slide the notched seal over both layers. The internal notching should be in direct contact with the strap surface: this is why the seal slides over the two layers without gaps. Center the seal, do not leave it at one end, and leave approximately 5-7 cm of free strap above for the tensioner to grip the excess.
The definitive test to distinguish a PET seal from a PP one is to look at the interior: the notching of the PET is clearly visible (serrated lines or notches on the inner face), while that of the PP is smooth. If you received a box without a label, inspect a seal before using it: applying a PP seal to PET strapping is one of the most frequent causes of claims for loosened cargo in export, because the smooth seal slips under the actual tension of the polyester.
Tension the strap without displacing the seal
Apply the tensioner to the free excess and tension progressively. PET allows higher tensions than PP: during this step, it is normal to feel more resistance in the lever. The seal must remain in position during tensioning; if it slips, reposition it before continuing. Once the correct tension is reached, hold the tensioner firmly to avoid losing tension before sealing.
Position the PET crimper over the seal
While holding the tensioner firm, open the manual crimper for PET strapping and center the jaws over the seal, perpendicular to the strap. The crimp must be symmetrical: the deep notching of the PET crimper needs to seat well on the seal to deform it correctly. Take an extra second to align; with heavy loads, the symmetry of the closure determines whether the seal holds up during transit.
Close the crimper with full and firm pressure
Squeeze the handles of the crimper all the way, in a firm and continuous motion. The PET buckle requires more force than the PP one, but the multiplied leverage of the specific crimper compensates for the difference. The notching of the crimper fully penetrates the two layers of the strap and deforms the seal against them: a single complete compression to the mechanical stop is what produces the correct closure.
Verify the closure and release the tensioner
Inspect the closed seal: the notching should have left visible and symmetrical marks on both layers of the strap, the seal should lie flat against the strap, and there should be no gaps. Pull on the closed strap: PET has elastic memory and may give slightly when tension is released, but it should not slip within the seal. If the closure is good, release the tensioner and cut the excess. If you notice slippage, repeat the closure with a new seal next to it before releasing the tensioner.
Does the notched seal work for your load?
If you have doubts about whether your load (weight, expected vibration, transit distance) requires a notched seal for PET or if PP would suffice, ask the virtual assistant. It helps you calibrate the choice before committing to the operation.
Complementary products
The notched seal is only the closure of the system: PET strapping requires specific strapping, tensioner, and crimper for polyester. These are the products that complete the cycle:
16 mm PET strapping is the material you will seal. The PET tensioner applies the higher tension required by polyester, and the specific PET crimper has deep notching and multiplied leverage to deform the notched seals. If your daily volume exceeds 100-150 closures, the battery-powered strapping tool integrates tensioning, thermal friction welding, and cutting in a single operation, and eliminates the use of metallic seals.
Maintenance and care
The seals do not require maintenance, but storage affects performance. PET seals are more critical than PP seals due to the notching geometry: any deformation affects the grip. These are the guidelines:
- Store the closed box indoors in a dry place. The galvanization protects against mild oxidation, but accumulated moisture in storage over months can form surface rust that reduces the integrity of the serration.
- Keep the box on a flat surface, with no weight on top: a crushed box can oval the serration of the seals at the bottom, which reduces grip on the strapping when closed.
- Do not mix PET seals with PP seals in the same dispenser or organizer box. Although the visible difference is the internal serration, in rapid operation, a selection error means heavy loads are improperly sealed.
- If you receive the box with dents or find it deformed after transport, inspect the serration of several seals before approving the batch: damaged or rounded serration does not bite the strapping correctly.
- For extended storage in a Caribbean climate, consider additional plastic wrapping or a sealed box: galvanization is standard protection, but sustained environmental humidity accumulates effects in the long term.
Do not use these PET seals with PP (polypropylene) strapping. The serrated teeth were calibrated to bite into the rigid surface of polyester; on PP strapping, the teeth tear the plastic tape when closed, which weakens the strapping and compromises the seal. For PP strapping, use only specific smooth seals. Applying the wrong seal is the most common cause of defective closures and visible damage to the strapping at the closing point.
Frequently Asked Questions
Why does the box of PET seals contain 600 units and the PP box contain 1,000?
Because the PET seal is physically larger and more robust than the PP seal: the serrated teeth and greater metal thickness add weight per unit. A PET box of 1,000 seals would weigh considerably more and be less convenient to handle. The 600-unit presentation keeps the weight per box within a reasonable operational range.
How many PET seals do I need per heavy-load pallet?
It depends on the geometry and weight of the package. For construction pallets (bricks, blocks, sacks), it is common to use three horizontal straps with individual seals and one additional vertical strap, totaling four seals per pallet. A box of 600 seals covers approximately 150 heavy pallets in this configuration.
Can I use PET seals in automatic strapping machines with a seal dispenser?
Only if the strapping machine is calibrated for PET serrated seals. Generic equipment sized for smooth PP seals may not handle the geometry of the serrated seal well and can cause blockages in the dispenser. Check your machine's manual; if in doubt, manual PET tensioners are always a safe alternative.