Mind the Gap: How Water-Activated Gummed Tape Prevents Pilferage and Tampering

What it is and how it works

Water-activated gummed tape (often called WAT, gummed tape, or kraft gummed tape) is made of paper—plain or reinforced—and coated on one side with a starch-based adhesive that becomes sticky when moistened. When the moistened tape is applied to corrugated cardboard and pressed down, the adhesive soaks into the cardboard fibers and forms a chemical/mechanical bond as it dries. That bond is effectively fused with the carton flaps, meaning the tape becomes an integral part of the box rather than just an external adhesive strip.

Why it helps prevent pilferage and tampering

Because the adhesive penetrates the box fibers, attempting to remove the tape typically damages the carton or the tape itself. A peeled seam will usually show torn paper fibers, ripped tape, or a residue pattern that makes resealing obvious. Reinforced versions that include fiberglass or synthetic filaments are even more tamper-resistant: they add tensile strength and make cutting or peeling the seal without visible damage much harder. In short, water-activated tape acts both as a strong physical seal and as a tamper-evident indicator—two properties that together deter opportunistic theft and make covert tampering difficult to conceal.

Common types and features

• Non-reinforced kraft tape: Paper tape for lighter loads and general sealing.
• Reinforced gummed tape: Fiberglass or synthetic filaments embedded for heavy cartons and freight.
• Printed/brandable tape: Custom logos, handling instructions, or security messaging printed on the tape.
• Security adhesives: Some formulations leave a "VOID" or pattern on removal to make tampering obvious.

Benefits compared to pressure-sensitive (plastic) tape

Water-activated tape is generally stronger and more tamper-evident than pressure-sensitive (PSA) plastic tape. Plastic tapes adhere to the surface of cardboard and can sometimes be lifted and re-applied, or cut and patched to hide tampering. WAT bonds into the board and makes the carton structurally stronger; it is also typically easier to recycle with corrugated cardboard, supporting sustainability goals. For high-value or sensitive shipments—electronics, pharmaceuticals, or luxury goods—gummed tape reduces the risk of undetected interference during transit.

Practical examples

1) An e-commerce fulfillment center ships high-value electronics. Using reinforced gummed tape with a printed company logo reduces shrinkage: employees and external carriers are discouraged from covertly opening cartons because any attempt will leave obvious damage and void the visible brand seal.

2) A pharmaceutical distributor uses WAT on cold-chain cartons. The strong bond ensures that cartons remain closed through handling and temperature variations, and any tampering is immediately apparent upon receipt by downstream handlers.

Best practices for implementation

• Choose the right tape: Match tape width and reinforcement to carton size and weight—heavier loads typically need reinforced tape 3 inches (75 mm) or wider.
• Use proper moistening: A consistent, even moisten is critical. Over-wetting can weaken corrugate; under-wetting reduces adhesion. Manual water brushes, dispensers with reservoirs, or automated gumming machines deliver consistent results.
• Apply firm pressure: After applying, run a roller or press firmly along the seam to ensure the adhesive penetrates and bonds.
• Train packing staff: Consistent technique—moistening, application, and pressure—reduces seal failures and wasted tape.
• Test and inspect: Conduct pull and opening tests on sample cartons, and inspect received goods for evidence of tampering regularly.
• Store properly: Keep rolls in a cool, dry place to prevent adhesive degradation and paper warp.

Common mistakes and pitfalls

• Poor moistening: Uneven or insufficient water application is the most frequent cause of weak seals.
• Wrong tape for the job: Using non-reinforced tape on heavy pallets or reinforced tape on delicate boxes without testing can lead to either failure or unnecessary cost.
• Lack of training: Inconsistent application techniques mean some cartons will be vulnerable even if most are properly sealed.
• Attempting to reuse or hide tampered tape: Trying to patch over damaged seals with clear plastic tape undermines the tamper-evident benefit and is easy to detect at inspection.

Integration with security processes

Gummed tape is best used as one piece of a broader anti-pilferage strategy. Combine it with documented chain-of-custody procedures, serialized labels or barcodes, CCTV at packing stations, and tamper-evident security seals for high-risk items. Custom printed tape with company name and warnings about tampering not only strengthens the bond but also communicates that the shipment is monitored, which itself is a deterrent.

Cost and sustainability considerations

Upfront costs include tape and potentially dispensers or automatic gumming machines; automated equipment has higher capital cost but increases throughput and consistency for large operations. Long term, many companies find that reduced shrinkage, fewer claims, and lower need for repacking justify the investment. From a sustainability angle, paper-based gummed tape is often recyclable with corrugated cardboard and avoids some of the plastic waste associated with pressure-sensitive tapes, aligning with corporate sustainability programs.

Simple implementation checklist

1. Assess carton sizes, weights, and security risk to choose tape type and width.
2. Select manual dispensers for low volumes or automated gumming systems for high throughput.
3. Train staff on moistening, application, and pressure techniques; run sample tests.
4. Introduce custom printing or security adhesives if additional tamper evidence is required.
5. Monitor results: record reductions in pilferage, damage claims, and feedback from carriers/receivers.

Closing note

Water-activated gummed tape is an effective, beginner-friendly option for organizations seeking to improve shipping security without complex technology. Its core advantage is the way it bonds with the cardboard itself—transforming a simple seam into a strong, tamper-evident barrier. When paired with proper technique and a broader security process, gummed tape can significantly reduce pilferage and provide clear, reliable evidence of tampering for both shippers and receivers.