Sealing NPT threads can be an exasperating experience if certain techniques are not followed. The following tips will help alleviate many common problems in thread sealing:

1. Always use some type of sealant (tape or paste) and apply sealant to male threads only. If using a hydraulic sealant, allow sufficient curing time before system is pressurized.

2. When using tape sealant, wrap the threads in a clockwise motion starting at the first thread and, as layers are applied, work toward the imperfect (vanishing) thread. If the system that the connection being made to cannot tolerate foreign matter (i.e. air systems), leave the first thread exposed and apply the tape sealant as outlined above.

3. When using paste sealant, apply to threads with a brush, using the brush to work the sealant into the threads. Apply enough sealant to fill in all the threads all the way around.

4. When connecting one stainless steel part to another stainless steel part that will require future disassembly, use a thread sealant that is designed for stainless steel. This stainless steel thread sealant is also useful when connecting aluminum to aluminum that needs to be disconnected in the future. These two materials gall easily, and if the correct sealant is not used, it can be next to impossible to get apart.

5. When connecting parts made of dissimilar meta ls (i.e. steel and aluminum), standard tape or paste sealant performs satisfactorily.

6. For sizes 2 and below, tape or paste performs satisfactorily. When using thread tape, four wraps (covering all necessary threads) is usually sufficient.

7. For sizes 2 1/2 and above, thread paste is recommended. If thread tape is used, eight wraps (covering all necessary threads) is usually sufficient. Apply more wraps if necessary.

8. For stubborn-to-seal threads, apply a normal coating of thread paste followed by a normal layer of thread tape.

9. For extremely-stubborn-to-seal threads, apply a normal coating of thread paste followed by a single layer of gauze bandage followed by a normal layer of thread tape. CAUTION: When this procedure is done, the connection becomes permanent. Extreme measures will be necessary to disconnect these components. All other measures to seal the threads should be explored prior to use of this technique.

10. Over tightening threads can be just as detrimental as insufficient tightening. For sizes 2 and below, hand tighten the components and, with a wrench, tighten three full turns. For sizes 2 1/2 and above, hand tighten the components and, with a wrench, tighten two full turns.