Choosing an Anaerobic Thread Sealant
There are three basic types of thread sealants for metal pipe; pipe dope, PTFE (ex. Teflon®) tape, and anaerobic sealants. Anaerobic sealants are often chosen due to the limitations of dope and tape. Pipe dope is inexpensive and easy to use; however, it is solvent-based, which means it shrinks, hardens, and can crack over time. Vibration in the pipes can hasten the leaks. PTFE tape, often called Teflon tape, is easy to store and use. It is called tape, but it is not sticky. The PTFE lubricates to ease assembly. Tape fills the space between the threads but doesn’t adhere. Any readjustment can cause the tape to shred, creating leaks or allowing pieces of tape to enter the fluid, causing blocked valves, filters, and screens.
Anaerobic thread sealants are 100% solids, so they do not shrink or crack like pipe dope. They cure to form a solid seal that resists vibration loosening. They can contain PTFE to lubricate and ease assembly.
Here is a short list of benefits of anaerobic sealants:
- No loose particles to clog values
- Will not shred, creep, or relax over time
- Will not shrink or crack
- Prevent vibration loosening
- Fully cured sealants typically seal to the burst pressure of the pipe
- Resistant to many chemicals
- Grades available for water, gas, air, and hydraulic systems
- Allow for directional freedom of the pipe
- Prevent corrosion
- Seals cut and mis-threaded fittings
- Lubricates to ease assembly
Which anaerobic thread sealant is best for the application?
The following table provides a description of several grades of Permabond thread sealants.
|LM012||Hydraulics Sealing Grade, |
MIL-S-22473E Grade HVV ASTM D5363
|Americas & Asia|
|LH050||General Purpose, UL Classified||Americas & Asia|
|LH050 PURE||NSF/ANSI 61 Certified, Potable Water Grade||Americas & Asia|
|LH056||Fire Protection Grade||Americas & Asia|
|LH150||Stainless Steel Grade, UL Classified||Americas & Asia|
|MH052||Medium Strength, BAM Approved for Oxygen||Worldwide|
|A1044||High Strength||Europe, Middle East, Australia|
|A131||Low Strength||Europe, Middle East, Australia|
|A129||Medium Strength||Europe, Middle East, Australia|
When not to use an anaerobic pipe sealant?
Anaerobic pipe sealants are only for use on metal pipe. Do not use on plastic.