Compression fittings offer a convenient and reliable method for joining pipes, but their effectiveness hinges on proper installation. A key component of this process is the use of pipe dope, a sealant that ensures a leak-proof connection. This guide explores the nuances of using pipe dope with compression fittings, addressing common questions and concerns.
What is Pipe Dope?
Pipe dope, also known as pipe thread sealant or pipe joint compound, is a lubricant and sealant applied to pipe threads to create a watertight seal. While various types exist, PTFE (polytetrafluoroethylene) tape is often favored for its ease of use and effectiveness. However, for compression fittings, the role of pipe dope is slightly different. It's not primarily for sealing threads, as compression fittings rely on the compression of a ferrule to create the seal. Instead, pipe dope in this context serves as a lubricant.
Should I Use Pipe Dope on Compression Fittings?
This is a crucial question. The short answer is: generally, no, you shouldn't use pipe dope on the threads of compression fittings. Compression fittings are designed to create a seal through mechanical compression, not a sealant. Applying pipe dope to the threads can interfere with this process, potentially leading to leaks or even damage to the fitting. The lubricant aspect of pipe dope is usually unnecessary because compression fittings generally have smooth, lubricated surfaces.
Why using pipe dope on compression fittings is often counterproductive:
- Interference with Compression: Dope can build up, preventing the ferrule from properly compressing against the pipe and fitting, leading to leaks.
- Contamination: Excess dope can contaminate the compression surfaces, reducing the effectiveness of the seal.
- Unnecessary: The design of compression fittings already accounts for lubrication and sealing. Additional lubricant isn't typically needed or beneficial.
What About Using Pipe Dope on the Pipe Itself (Before the Fitting)?
Some plumbers might suggest applying a small amount of pipe dope to the pipe itself, just before inserting it into the compression fitting. This is done primarily to aid in the insertion and prevent scratching the pipe's surface. However, this practice is also debated. Use extreme caution if considering this approach. Apply only a very thin film and ensure it doesn't interfere with the compression process.
What Type of Sealant Should I Use with Compression Fittings?
The best sealant for compression fittings is none. Rely on the designed compression mechanism. Trying to supplement this with additional sealant is often counterproductive.
What Happens if I Accidentally Use Pipe Dope on a Compression Fitting?
If you've accidentally applied pipe dope, try to carefully wipe it off with a clean cloth before assembling the fitting. If this isn't possible, proceed with extreme caution, carefully observing the fitting's compression and ensuring a proper seal.
Troubleshooting Leaky Compression Fittings:
If you're experiencing leaks with compression fittings, the issue is almost certainly not due to a lack of pipe dope. Instead, consider these factors:
- Proper Tightening: Ensure the fitting is tightened sufficiently but avoid over-tightening, which can damage the fitting.
- Pipe Condition: Check for damage or debris on the pipe that might prevent a proper seal.
- Fitting Compatibility: Ensure you're using the correct fitting for your pipe material and size.
- Ferrule Condition: Make sure the ferrule is undamaged and properly seated.
In conclusion, while pipe dope serves a crucial function in threaded pipe joints, its use with compression fittings is generally discouraged. Relying on the compression mechanism and ensuring proper installation techniques are far more effective in preventing leaks and ensuring a long-lasting, reliable connection. If you encounter leaks, focus on proper installation techniques rather than seeking a solution with additional sealant.
