Duct Tape

Duct tape is a durable, pressure-sensitive adhesive tape with a cloth backing and a polyethylene coating. It is known for its versatility, strength, and water resistance.

Description of what it is like

It typically comes in silver or black rolls. It has three layers:

1. Top layer: A thin film of polyethylene (plastic) that provides waterproofing.
2. Middle layer: A fabric mesh (cotton scrim) that gives it tensile strength and allows it to be torn by hand.
3. Bottom layer: A thick, rubber-based adhesive that sticks to almost anything.

Origin and where to find it

• Scavenging: Hardware stores, workshops, garages, industrial sites, and homes.
• Signs: Look for rolls in toolboxes or supply closets.
• It is a manufactured product.

Minimum processing required

• None: It is ready to use straight off the roll.
• Cleaning surfaces: For best adhesion, the surface should be clean and dry before applying.

Improvised Manufacture:

While true duct tape is industrial, a functional substitute can be made:

1. Backing: Cut strips of Cotton or Canvas.
2. Waterproofing: Coat one side with Resin, Beeswax, or Tar.
3. Adhesive: Apply a sticky layer of Pine Resin Glue (resin mixed with charcoal) or Natural Rubber to the other side.
4. Assembly: Press the adhesive side onto the target surface.

Tools needed to work on it

• Hands: It is designed to be torn by hand across the width.
• Knife/Scissors: For cleaner cuts or longitudinal strips.

Common forms of use

• Repairs: Patching holes in tents, clothing, or containers.
• Sealing: Closing gaps in windows, doors, or ducts (originally for ammo cases, not air ducts!).
• Binding: Strapping items together, splinting broken bones (over padding).
• Cordage: Twisting it makes a strong rope.
• Fire Starter: It is flammable and can be used as tinder.

Possible substitutes

• Tarred Canvas: Cloth impregnated with tar or pitch for waterproofing.
• Birch Bark & Pitch: Natural waterproof patches glued with resin.
• Rawhide: Wet rawhide shrinks as it dries, binding things tightly.
• Electrical Tape: Less strong, stretchier.

Limitations and common failures

• Heat: The adhesive can melt and become messy in high heat.
• Cold: Adhesion fails in freezing temperatures.
• UV Light: The plastic backing degrades and cracks in sunlight over time.
• Residue: Leaves a sticky mess when removed.

Risks and safety

• Skin Irritation: The adhesive can irritate skin if left on for long periods.
• Circulation: Do not wrap tightly around limbs as a tourniquet unless intended; it does not stretch and can cut off blood flow.
• Flammability: Burns vigorously with toxic smoke.

Related materials

• Plastic: The waterproofing layer.
• Cotton: The scrim layer.
• Natural Rubber: The adhesive base.
• Glue: The adhesive component.
• Pine Resin Glue: An improvised adhesive alternative.