Fitting a pipe cap is usually as simple as screwing a compatible threaded cap onto the threaded end of the pipe.
Here's a step-by-step breakdown:
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Select the Correct Cap: Make sure the pipe cap has threads that exactly match the threads on the pipe you're capping. Using the wrong cap can damage the threads of both the pipe and the cap, leading to leaks or a permanently stuck cap. Different pipe materials (PVC, metal) have different thread types and sizes.
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Clean the Threads: Before fitting the cap, ensure both the pipe threads and the cap threads are clean and free of debris. This will help ensure a tight seal and prevent damage.
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Apply Thread Sealant (Recommended): For a secure and leak-proof seal, apply thread sealant, such as Teflon tape or pipe dope, to the male threads (usually on the pipe). Wrap the Teflon tape clockwise as you look at the open end of the pipe. Don't overdo it; a couple of wraps or a thin layer of pipe dope is sufficient. This helps fill any imperfections in the threads.
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Hand Tighten: Start by screwing the cap onto the pipe by hand. Turn it clockwise until it's snug and you can't easily turn it further.
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Wrench Tighten: Use a pipe wrench or adjustable wrench to tighten the cap further. Be careful not to overtighten, especially with plastic (PVC) pipes, as this can crack or damage the pipe or cap. A quarter to a half turn past hand-tight is generally sufficient.
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Inspect for Leaks: After turning on the water supply, check for leaks around the cap. If you see any, tighten the cap slightly more. If it continues to leak, you may need to remove the cap, reapply thread sealant, and re-tighten.
Important Considerations:
- Type of Cap: There are different types of pipe caps (e.g., threaded, slip-on, weld-on). This guide focuses on threaded caps, which are most commonly used for temporary or removable closures. Slip-on caps require solvent welding (for PVC) or soldering/brazing (for copper). Weld-on caps require welding.
- Material Compatibility: Ensure the cap material is compatible with the pipe material. Avoid using dissimilar metals that can cause corrosion.
- Pressure Rating: Choose a cap with a pressure rating suitable for the system it's being used on.
- Plugs vs. Caps: A plug screws into a fitting, while a cap screws onto a pipe end. The same principles of thread matching, sealant, and tightening apply.
