How to Spec Filament Tape for Heavy-Duty Bundling: Mono vs. Bi-Directional, and the Numbers That Actually Matter

A buyer calls and asks for “your strongest filament tape.” We can ship it. But roughly half the time it is the wrong answer, because the highest tensile grade in our range also has one of the lowest peel values. Tensile is what people ask for. Peel and holding power are what decide whether the bundle survives. This is the selection logic we use internally.

1. What filament tape is actually for (and what it is not)

First, clear up a common mistake. Filament tape is not a stronger version of carton sealing tape. Carton sealing tape holds a closure together; filament tape carries a load. Different job, different spec.

Where it earns its place:

• Bundling and unitising. Holding pipe, bar stock, extrusions, timber or cable into a shippable unit.
• Component securing in transit. Shelves, trays and panels inside a refrigerator or washing machine that must not shift between factory and installation.
• Reinforcement. Bridging a weak point — a seam, a corner, a splice — rather than carrying the whole load.
• Heavy structural bundling. Steel cable, wire rope and bridge strand, where the tape is a permanent part of the assembly.

Why buyers move to it from strapping: no tools, no tensioner, no PPE, no cut ends, no damage to coated or painted surfaces, and it conforms to irregular shapes that strapping cannot. It also takes print, which matters when the bundle carries a part number.

2. The first fork: mono-directional, bi-directional or double-sided

This is the decision that matters most, and it has nothing to do with strength numbers.

The one-line rule: if it goes around the load, mono-directional. If it sits on a surface and resists stress from more than one direction, bi-directional. If it joins two faces, double-sided.

3. Never spec on tensile alone — read three numbers together

Every TDS gives tensile, peel adhesion and holding power. They pull against each other, and picking on tensile alone is the most expensive mistake in this category.

• Tensile strength — resistance to being pulled apart along the roll. This is the headline number.
• Peel adhesion (90°) — how hard it grips the surface. High tensile with low peel means the tape is strong but lets go of the substrate.
• Holding power — resistance to slow creep under sustained load. This is what fails on a pallet three weeks into a sea voyage.

Our own range makes the point clearly:

Each pair normalised against the highest value in that property: JLT-696 = 472 lbs/in, JLW-306 = 137 oz/in. Note how the ranking inverts.

4. Selection by application

These are the pairings we use most often. All figures are lab averages from the relevant TDS.

The high-elongation special case: JLT-5160

JLT-5160 is the odd one out, and it catches people on two counts.

It is built for wrapping and reinforcing rather than straight bundling, with 25–28% elongation at break against the 3–7% typical of the rest of the range. It stretches to conform over irregular shapes and absorbs impact instead of snapping. It is specified for heavy bundling, pipe wrapping, pallet securing and reinforcing bridge steel cable.

5. When clean removal is not optional

Eleven grades in our range carry a clean-removal adhesive. If any of the following is true, one of them is the right spec:

• The tape goes on a visible or painted surface that the end customer will see.
• There is a rework or service step downstream — the tape gets removed before the unit ships or is repaired.
• Residue would contaminate the product (appliance interiors, electronics, coated steel).
• Your customer's inbound inspection rejects residue on principle.

The clean-removal mono-directional range, by tensile:

Machine-direction tensile, lbs/in. JLT-696 and JLT-609 are 9.1 and 7.8 mils; JLT-602D at 4.7 mils is the thinnest in the group. JLT-6614A plus JLT-695 extend the temperature range to 100°C (212°F).

6. Five specification traps

1. Ordering mono-directional where bi-directional is needed. Mono grades are strong along the roll and weak across it by design. On a load squeezed from the side, or on anything that will get punctured, a mono grade splits. The JLW cross-hatch exists for exactly this.
2. Chasing tensile and ignoring peel. JLT-696 has six and a half times the tensile of JLW-306 and about a third of the grip. If your failure mode is the tape letting go of the surface, more tensile changes nothing.
3. Comparing JLT-5160 against 25 mm figures. Its 1800 N is measured on a 40 mm specimen. Convert before you compare.
4. Assuming JLW-308 is defective. Its peel adhesion is zero — the surface is deliberately non-sticky, for internal bundling where the tape must not adhere to the product. It is a feature, and it is the wrong tape for anything that needs to grip.
5. Ignoring temperature. Standard grades run -5 to 70°C (23 to 158°F). Most clean-removal grades reach 80°C (176°F). Six grades reach 100°C (212°F): JLT-695, JLT-6614A, JLW-315, JLW-315C, JLW-316BG and JLW-396FR. Above that, none of our filament tapes are rated — ask us rather than assuming.

On test data: every figure here is a lab average from ASTM and GB/T dual-standard testing. Elongation runs 3–7% across most of the range. Total thickness spans 3.9 to 11 mils (0.10 to 0.28 mm). Shelf life is one year from date of shipment for every grade in this family. We would rather you sample and run it on your own load than buy off a number on a page.

The short version

Filament tape selection is three decisions, not one. Choose the structure first — mono for wrapping, bi-directional for surface stress, double-sided for bonding. Then choose the balance of tensile, peel and holding that matches your actual failure mode. Then check temperature and removal. Get those right and you can usually drop a grade and a price point rather than climb one.