Thread Tapes Information

Thread seal tape are used to seal, lubricate, and prevent seizure on threaded bolts, studs, and fittings. They are commonly referred to as:

• Teflon tape
• PTFE tape
• PTFE thread seal tape
• plumbers waterproof tape

Thread tapes are usually made of polytetrafluoroethylene (PTFE), a highly crystalline, perfluorinated polymer that is better known by its DuPont brand and registered trademark—Teflon. PTFE tape has an extremely low coefficient of friction, good chemical resistance, and good heat resistance. Chemical inertness prevents cross-linking and makes PTFE thread tapes a good choice for applications that involve corrosive chemicals such as liquid oxygen, or caustics such as ammonium hydroxide. Thread tapes can also be made of polyethylene (PE), a low-cost plastic that resists water and many chemicals.

Specifications

Thread tapes carry specifications such as:

• density
• tensile strength
• elongation
• dimensions
• substrate compatibility

PTFE thread tape manufacture  describe their products as either high-density or low-density. High-density PTFE thread tapes usually have a density of .70 g/cm3 or 1.2 g/cm3. Low-density PTFE thread tapes usually have a density of .37 g/cm3. Tensile strength is the force required to break a piece of thread tape by pulling on opposite ends. Elongation is the fractional increase in a thread tape’s length due to stress in tension or to thermal expansion. Important dimensions for thread tapes include length, width, and thickness. With regard to substrate compatibility, some Teflon tapes are designed for use with pipes, tubes, or conduits made of aluminum, black iron, or brass. Other PTFE thread seal tape adheres to chrome, copper, glass, plastic, or rubber.

Standards

PTFE thread seal tapes follow two basic quality standards and are color-coded for a variety of applications. MIL-T-27730A is a U.S. military specification (MIL-SPEC) that specifies a minimum thickness of 3 mils. A-A-58092 is a commercial standard that maintains the thickness requirement of MIL-T-27730A, but adds a minimum density standard. White PTFE thread tape provides tight seals for a variety of threaded joints and is suitable for most plumbing and potable water systems. Yellow PTFE thread tape is designed for use with pipes, conduits, bolts, valves, and threaded gas lines that carry air, ammonia, butane, chlorine, or hydrogen. Pink Teflon tape is made of heavy-duty, industrial grade PTFE and is used in commercial or industrial plumbing applications. Green Teflon thread tapes may be used in oxygen-handing applications.

The above information is from PTFE tape machine manufacture, and we hope above information can help you know a general idea of PTFE Teflon tapes. 

When to use PTFE Teflon Yellow or White tapes or Pipe Dope

                         When to use White PTFE Teflon Tape  or Yellow tapes or Pipe Dope

The purpose of thread seal tape (a.k.a. “Teflon tape”) or pipe dope is threefold:

• First, the lubricant qualities allow male threaded pipe to be turned deeper into female threaded fittings to prevent leaks;
• Second, it acts as a filler to smooth out micro abrasions or surface irregularities on threads;
• Third, it keeps the male and female threads from rusting together (a.k.a. seizing);

PIPE THREAD TYPES

AN thread is a type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid (it stems from a joint standard by the U.S. Army and U.S. Navy, hence “AN”).

AN thread provides a positive seal that should seal correctly with specified torque torque range with no leaks. The AN should not require a thread sealant.

National Pipe Thread (NPT) taper is a U.S. standard for tapered threads used on threaded pipes and fittings.

In contrast to straight threads that are found on a bolt, a tapered thread will pull pipes and fittings tight together, providing effective seal for pipes transporting liquids, gases, steam and other fluids.

Although SAE and ASTM (organizations that set U.S. industry standards) set very precise thread class specifications, many threaded products carried by large box retailers have varying degrees of deviations from set specifications (i.e. micro surface imperfections like chatter or spalling), thus requiring a use of thread sealants.

PTFE  SEAL THREAD TAPE

When a Teflon seal tape was first introduced, it only came in a single density type (“white Teflon tape(1)“) that was commonly found in large home improvement stores. Later they began making a double density version, which was twice as thick in the same color (unfortunately with the same “white” color).

(1)Teflon tape is used ubiquitously when referring to a thread sealant tape. However, the word “Teflon” is a trademark name owned by Dupont Chemical Corp. Although Dupont no longer manufacturers Teflon tapes, it still enforces its trademark rights. That is why you see other manufacturers like Oatey refers to it as PTFE (PolyTetraFluoroEthylene) thread sealant tapes.

One very important thing to remember is that PTFE thread sealant tapes and pipe joint compounds are only to be used on NPT male threads. Neither should be used on SAE mechanical threads or as a gasket sealer (i.e. sink basket gasket).

Teflon THREAD SEAL TAPE COLORS

Since many state and local codes adopted the use of double density tapes when making connections for natural gas, the use of same color for two different thickness presented a challenge when time came to inspect a job. Thus, a “yellow TEFLON tape” was later introduced for such application.

Since then, ASTM has broadened the specifications for PTFE tape colors:

• White, single or double density, should only be used on NPT threads up to 3/8 inch in diameter
• Yellow,double density, often labeled as “gas tape”
• Pink, triple density, required on all joints 1/2″ or larger
• Green,Oil Free PTFE tape, required for use on all lines carrying oxygen (i.e. – medical oxygen or welding oxygen lines)

The above information is from PTFE tape manufacture and we hope the above information can help you understand types of Teflon thread seal tapes.