Do Flare Fittings Need Teflon Tape?
The question of whether to use Teflon tape on flare fittings is a common one among both professional plumbers and DIY enthusiasts. In this article, we’ll explore the correct way to seal flare fittings, addressing misconceptions and providing practical advice.
Understanding Flare Fittings and Sealing
Flare fittings are commonly used in gas and hydraulic systems to create a leak-tight seal between two components. The term 'flare' refers to the flared end of the pipe, which mates with the flare fitting to form a secure joint.
Do Not Use Teflon Tape
It is never recommended to use Teflon tape or any other thread sealant on flare fittings. The threads on these fittings are designed for a different purpose than sealing. Instead, the flared end of the pipe is inserted into the flare fitting, where it forms a metal-to-metal seal due to the precise beveling and tapering of the surfaces. Applying tape can lead to water intrusion and contamination of the seal, which is unacceptable in critical applications such as gas and hydraulic systems.
Why Teflon Tape Is Not Needed
The bevels on both the pipe and the flare fitting are designed to interlock and create a seal. This metal-to-metal contact is the primary seal for these fittings. Teflon tape is primarily used for tapered threads, such as NPT (National Pipe Tapered), where the threads themselves create the seal. For flare fittings, unnecessary sealants can cause issues.
Proper Sealing Without Tape
In most cases, the flare connection is designed to seal properly when the flared end of the pipe is inserted into the fitting. No additional sealant is needed. If the joint fails to seal properly, the first step should be to check the cleanliness and condition of the union faces. If the joint still does not seal, it may be necessary to replace the damaged parts.
Add Anti-Seize Against Corrosion
While it’s crucial not to use Teflon tape, you can use a small amount of Teflon paste as an anti-seize compound. This paste can help prevent corrosion and improve long-term performance by acting as a barrier between metal surfaces. However, this is more of a maintenance measure and not a sealant.
Conclusion
The use of Teflon tape on flare fittings is not only unnecessary but can also be detrimental in many cases. Flare fittings rely on the precision of their design to create a reliable seal. If you encounter any issues with your flare joints, ensure that the parts are clean and properly installed, and consider the use of anti-seize paste for maintenance purposes. By understanding and applying the correct sealing techniques, you can ensure that your plumbing systems remain efficient and leak-free.