What does overtightening a threaded connection do to a 12mm-teflon-tape?

Overtightening a threaded connection with 12mm Teflon tape applied can have several negative consequences and may compromise the effectiveness of the seal. Here's what can happen when a threaded connection is overtightened with Teflon tape:

Tape Damage: Excessive torque during overtightening can cause the Teflon tape to tear, shred, or deform. This damage can result in gaps or inconsistencies in the tape's coverage on the threads.

Tape Extrusion: Over-tightening can push excess Teflon tape out from between the threads, creating tape extrusion. This extruded tape can block the flow of fluids or create an irregular seal, leading to leaks.

Thread Damage: The excessive force applied when overtightening can damage the threads of both the male and female components. Thread deformation or stripping can occur, making it difficult or impossible to achieve a secure seal.

Increased Stress: Overtightening increases the stress on the threaded connection, which can lead to fatigue and potential failure over time. The increased stress may cause the joint to weaken or crack, resulting in leaks or ruptures.

Distorted Tapered Threads: For tapered threads, such as National Pipe Taper (NPT) threads, overtightening can distort the threads' shape and interfere with the proper sealing action of the Teflon tape. This can compromise the effectiveness of the seal.

Difficult Future Maintenance: If a connection is overtightened and the threads are damaged, it can be challenging to disassemble and perform future maintenance or repairs. This may require replacing components or re-threading, resulting in additional time and cost.

Typically, hand-tightening followed by a quarter-turn or half-turn with a wrench or pliers is sufficient for most threaded connections. Using a torque wrench can also help ensure that you apply the appropriate amount of force without over-tightening.

Remember that Teflon tape is designed to provide an effective seal with the right amount of compression, and excessive force can compromise its ability to maintain a leak-free seal. Proper installation practices, along with the correct use of Teflon tape, will help ensure the integrity and reliability of threaded connections in plumbing and piping systems.