Duct tape is a good solution for a lot of things. It’s durable. It’s waterproof. It’s inexpensive. You can tear it easily with your hands. Yet there’s one thing duct tape isn’t good at: sticking to cardboard.
Do Not Use Duct Tape for Shipping
Duct tape is not a good solution for taping packages, boxes, or palletized cargo. Duct tape tends to come unstuck from cardboard.
Why is this? Duct tape works so well on other surfaces. Why is it so bad with cardboard?
Duct tape’s adhesive layer is pretty thin. This means that its adhesive sticks to the highest points on a surface. It sticks to plastic pipes well because plastic offers a smooth surface. Cardboard is bumpier and has a certain amount of “cardboard fuzz” on it.
Go ahead and run your hand over cardboard. It holds its shape – it’s structurally rigid. But do you notice how the surface itself is soft? With a well used box, you may even feel little bits of cardboard come off in your hand like dust rolling off a surface. Duct tape sticks to the raised elements of cardboard without doing a good job of sticking to that rigid structure underneath.
Why is Duct Tape Like That?
This is also why duct tape doesn’t do a good job of sticking to dusty surfaces. You’ll notice that the duct tape will pick up the dust and stop being very sticky. Even a thin layer of dust can be enough to neutralize the thin layer of adhesive that duct tape offers.
This thin layer has a purpose – it makes duct tape easy to tear and useful for creating short-term waterproofing. More than this, it makes duct tape very flexible. It will fit its shape to almost anything, making it perfect for strengthening awkward joints. This makes it great for HVAC work – that’s why it’s called “duct” tape.
This same property makes it a bad option for international shipping. Look for shipping tape or filament tape as better options that will remain adhered to cardboard and that can hold palletized cargo together, or the weight of a full box.