June 24, 2023

Thread Sealants: The Ultimate AU/NZ Plumbers' Guide

You walk into your local hardware store and head straight for the plumbing parts aisle in search of some more handy PTFE tape for your upcoming jobs. You finally find the aisle, but as you look up at the shelves you remember the other thread sealants out there – to the right you see a row full of thread-sealing compound in small bottles and even tubes of anaerobic thread sealants. You take a step back and pause for a minute to think – which one should I choose?

In the world of plumbing, we all know how important it is to ensure tight and leak-free connections for a long-lasting plumbing system. There are a variety of different thread sealants to choose from, and it’s important to choose the right one for the job – and we’re going to explore the differences between each option.



Types of Thread Sealants

The most common thread sealants in the Australian and NZ market include:

  • Thread Seal Tape (also known as PTFE tape or Teflon tape)
  • Thread Sealing String (also known as thread sealing cord)
  • Thread Sealing Compound (also known as thread paste)
  • Anaerobic Thread Sealant (also known as thread-locking adhesives)


Thread Seal Tape

Thread seal tape is a thin, non-adhesive tape usually made of PTFE. It makes a quick and easy option for sealing small-diameter pipes for DIYers, homeowners, and maintenance plumbing applications. Because it’s applied by wrapping, it’s also easy to undo. Because of its unlimited shelf life and small size – it’s a great option to keep in your toolbox especially if you’re needing it for occasional or emergency use.

Thread Sealing String

Thread Sealing String is very similar to Thread Seal Tape but comes as a dental-floss-like string. Just like the tape, it is also made of PTFE and holds the same benefits and uses as the tape. The choice between thread-sealing tape and string usually comes down to personal preference. Thread sealing string doesn’t require as much attention as thread seal tape (there’s no need to try and lay it flat without creases), but it requires more wrapping for a proper seal.

Thread Sealing Compound (Thread Pastes)

Thread sealing compound is a thread sealant that is usually solvent-based. Solvent-based thread-sealing compounds work by hardening as the solvent evaporates.

Thread sealing compounds often come in a bottle with a brush attached inside the cap – however, it can also be purchased as a squeezable tube or stick. Pipe thread compound can be used for similar applications to PTFE tape and string – for DIYers and professional maintenance plumbing applications.

Thread sealing compound also has the advantage over PTFE tape and string when sealing threads on larger pipes, as it’s easier to apply. However, its limited 2-year shelf life makes it less ideal for homeowners and DIYers and professional maintenance plumbing applications.

Thread sealing compound also has the advantage over PTFE tape and string when sealing threads on larger pipes, as it’s easier to apply. However, its limited 2-year shelf life makes it less ideal for homeowners and DIYers looking to have a thread sealant in their toolbox for occasional use. Because it is solvent-based it can also shrink and crack over time, creating potential for it to pull away from the thread walls and allowing leaks to result.

Anaerobic Thread Sealant (Thread Locking Adhesive)

Anaerobic thread sealants are high-performance sealants that only cure when oxygen is expelled, so they do not shrink or crack like thread sealing compound does. They work by curing to form a solid seal that is shock and vibration resistant – making them a must-have for professional jobs such as permanent fixtures in commercial plumbing applications. They can also be used for many other thread-sealing applications that don’t involve plastic.

Anaerobic thread sealants often come in a convenient bottle with a nozzle – making it easier, faster and less messy to apply when compared to pipe dope. In the case of the Loxeal 58-11, this sealant can withstand high-pressure gas lines (maximum working pressure of 2000KPa) and is safe to use on plumbing systems for potable water.

Just like thread paste, anaerobic thread sealant have a limited shelf life and must be discarded after its expiry date. Once cured, it can be much more difficult to remove, which can make repairs and replacements challenging.

Features to Consider

When deciding which type of sealant is best for the job you’re about to tackle, there are several things to keep in mind:


Anaerobic thread sealants do not shrink or crack like pipe dope over time as they only cure when oxygen is expelled. They work by curing to form a solid seal that is shock and vibration resistant. If you are sealing permanent fixtures, particularly under commercial plumbing, choose an anaerobic adhesive for the most high-strength bond.

Pipe System

If you’re sealing gas lines, make sure that the sealant is AGA-approved and has a suitable maximum working pressure and temperature. If using for waterlines, make sure the sealant is WaterMark approved for potable water. If you know the pipe will be exposed to certain acids, oxidizers, alkalis and chemicals – make sure your selected thread sealant can be used with these by checking the Safety Data Sheet.

Material of Pipe Threads

Most thread sealants can be used for sealing metal to metal threads, however, not all thread sealants can be used on all thread types. For example, the Loxeal 58-11 cannot be used on plastic threads.

Ease of Use

Thread seal tapes are quick and easy to use for smaller pipe threads and are also great for beginners as they can easily be undone. If you plan to seal larger threads, a paste or liquid thread sealant will be much more convenient. Look for a nozzle tip over a brush head for ease of use and less mess.

Shelf Life

If you’re only planning to use a thread sealant for the occasional use or a backup in your toolbox, you may want to consider PTFE tape over a liquid or paste thread sealant for its unlimited shelf life.

Handling and Curing Time

PTFE tapes do not require curing, whilst pipe dopes and anaerobic thread sealants may require some time before handling. Anaerobic thread sealants require additional curing time for a solid seal.

Bromic’s Top Thread Sealants

SUPA-SEAL P.T.F.E. Thread Seal Tape

SUPA-SEAL P.T.F.E. Thread Seal Tape is the perfect toolbox companion for sealing gas threads – suitable for DIYers, home-owners and professional maintenance applications. SUPA-SEAL is designed to be breakdown resistant, especially in connection with bending and vibrations and provide high tensile strength, even at low temperatures. It’s also resistant to almost all types of acids, bases, solvents, and chemicals (unsuitable for fluorine, fluoride, and melted alkalis).
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LA-CO Slic-tite® Thread Sealing Compound

LA-Co’s Slic-tite® Thread Sealant has been a trusted solution for sealing air, steam, natural gas, and more for decades. It’s a highly versatile thread sealant that can be used on a variety of metals and plastics and is AGA-approved for pressure systems.

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LOXEAL 58-11 High-Pressure Thread Sealant

LOXEAL 58-11 is a high-performance anaerobic thread sealant that can be used on high-pressure gas systems and systems that contain potable water. It’s a great option for a wide range of plumbing jobs including permanent fixtures in commercial plumbing applications. It’s shock- and vibration-resistant and suitable for temperatures between -55°C and +150°C. It’s no-mess nozzle makes thread sealing easier and faster. Loxeal 58-11 is available in 50mL, 100mL and 250mL tubes.

Learn More

Where to Buy

SUPA-SEAL, LA-CO and LOXEAL Thread Sealants can be purchased at a number of stores across Australia – you can enquire with your local supply store to check for what is in stock. SUPA-SEAL P.T.F.E. Thread Seal Tape is available at Total Tools and Doug Smith Spares. LA-CO Thread Sealing Compound and Loxeal 58-11 can be purchased at Bunnings and Plumber’s Choice.


Thread sealants, PTFE tapes, leak detector and tap grease for commerical and residential plumbing.

Bromic Plumbing & Gas