Although both are used to seal threads, Teflon and hemp work in mechanically different ways. Here are the main differences:
|
Teflon |
Hemp and paste |
Material |
Synthetic, chemically inert. |
Natural fiber (hemp) + sealing paste. |
Mechanism |
Creates a layer that fills the gaps. |
The fiber swells on contact with water. |
Ease of use |
Very clean, ideal for beginners. |
Messier, requires manual skill. |
Resistance |
Excellent for chemicals and gas. |
Excellent for high temperatures and vibrations. |
Repositioning |
Impossible: if you unscrew, it leaks. |
Possible: allows small adjustments. |
When to use hemp with green paste
Hemp is the "traditional" choice preferred by professionals for metal pipes (iron, steel, brass), especially medium to large diameter ones.
The secret advantage of hemp
Hemp is dynamic. If a micro-crack forms, the fiber absorbs a little moisture, swells, and seals the leak on its own.
Adjustment: Unlike Teflon, hemp allows you to slightly unscrew the fitting (for example, to align a faucet) without compromising the seal.
When to use Teflon (PTFE) tape
Teflon has become the modern standard, especially for small jobs and delicate materials.
Plastic materials: It is mandatory on PVC or plastic fittings, where hemp could swell too much and crack the thread.
Gas and air: There are specific high-density tapes (often thicker) certified for gas, where hemp is not recommended.
Cleanliness: Ideal for visible installations or where you don't want to make a mess with sealing paste.
Pro Tip for a perfect seal
If you use hemp on very smooth fittings (such as chrome-plated brass ones), lightly scratch the threads with a hacksaw blade. This will create small notches that prevent the hemp from sliding off during tightening.
