Are you worried about damage to your irrigation system pipes? To avoid unnecessary headaches, then you should consider bypassing potential leak points.
Threading is the process of joining one end of pipe to another, particularly using 80 or 120 grade material. If you are thinking of doing this project yourself then be sure to follow this guide on how to thread pipe from PVC.
Required tools
- Vise
- Taper shaft/tail
- Threading die made for plastic pipes, compatible with a pipe diameter of 1 inch
- Die cast
- One inch PVC pipe with a schedule 80/120 wall thickness
- Wooden plug
- Pipe cutter with ratchet
- The cloth
- Bucket
You can also use a pipe threading kit, which contains most of the components mentioned above.
How to thread PVC pipe?
Threading a PVC assembly of the joint can be done in 4 simple steps:
1. Secured
First, wrap a cloth around the part of the pipe that will come into contact with the clamp. This will help protect this piece from breaking.
Next, place the pipe in the vise. Make sure the threaded end is 6 to 8 inches away from the clamp.
Tighten the pipe, but do not overdo it. You’ll end up breaking it, which means you’ll have to buy a new one.
Pro tip: You can also put a wooden plug in the pipe. This will help prevent distortion of the walls of the female program.
2. Prepare
Place the taper shaft inside the PVC pipe. This will help maintain balance and stability. The arbor will also keep the hand threader centered, apart from protecting the sides of the pipe from cracking.
Pro tip: It helps to put a bucket under the end of the pipe. This will catch the mess that comes with the threading, making cleanup easier.
3. Thread
Place the threading device inside the pipe. Place the smooth side of a piece of plastic first so that the threads are facing away from the pipe.
Start the wire mold. You can use a mold with guides as this will ensure that the mold is square to the axis of the pipe. Do not forget to remove the parts of the guides that could damage the pipes.
Turn the cutter clockwise. Make sure you push the mold as you connect the pipe. This will ensure that each successive thread is even.
Rotate the long die handle to continue threading.
Thread the threaded portion onto the pipe. Stop once the mold is in line with the end of the pipe.
Pro Tip: Don’t use plastic pipe dies to cut another type of material.
4. Clean up
Turn the mold counterclockwise to remove it. Remove the pipe from the vise.
Do not forget to wipe the threads with a cloth. As for the mold, keep it clean and sharp for future use.
How to assemble threaded PVC pipes?
Now that you have finished threading the PVC pipe, then you may want to move on to assembling the threaded fittings. The materials you need for this project are as follows:
- Teflon tape or sealant
- Belt Wrench/Crescent Wrench
Once you have them in hand, you can proceed with the following steps:
1. Lubricate the joint
To ensure that the plastic fitting abuts well, you will need to lubricate the joint. This will prevent liquids from leaking out.
When fixing threaded PVC pipes, you can use either of these two components:
Apply the sealant evenly to the male PVC fittings. Fill the threads, but don’t over-apply (as most plumbers tend to do.) You don’t want the excess sealant to clog some of the pipe components.
Remember: always make sure you use the right sealant. Make sure it contains a non-curing compound. This will provide a true sealing function as they do not harden in place.
Instead, they are pushed into areas where leaks can occur due to high water pressure.
Although some claim that sealant is better than Teflon tape, you can use it when assembly of socket fittings.
According to this video, the best material to use for this project is white PTFE tape. Dimensionally, the recommended tape thickness should be 3 mils. As for the width, it should depend on the size of the fitting.
When applying Teflon tape, make sure the threads are clean first.
Next, hold the fitting in one hand and line up the edge of the tape over the wires. Press the end of the strip with your thumb. Twist the tape around the fitting clockwise. Apply enough force to gently stretch the tape, but do not tear through it.
Remember: 2 or 3 rotations should be enough!
Pro tip: Make sure the tape covers the first thread, but not the edge of the fitting.
2. Secure the threaded joint
After you’ve covered the fittings with tape or the appropriate sealant, it’s time to fasten them together.
That said, it’s important to tighten them with your finger.
You can add a turn or two, but that’s all with a belt or crescent wrench. Do not use a wrench that can damage the pipe and do not make extra turns as it will affect the tensile strength of the one inch PVC.
As for why the latter happens, it boils down to the difference between a male plastic fitting and a female fitting.
Male threads have a larger diameter, while the female side has smaller diameter fittings. This amount of taper ensures that they connect well with each other.
As the pipe size decreases in a female adapter, this means the resistance of the PVC in this part is lower also. The tension of the male thread can lead to high levels of tensile stresses, thus making the female head more prone to cracking.
To make matters worse, since you applied before caulking or tape, add some form of lubrication to the fitting. The help of such lubricants can cause you to apply more torque – this is another reason why you can end up overtightening it.
Pro tip 1: Do not remove the fittings back after turning them. Doing so could damage the threads and cause more leakage in the long run. That’s why you need to be sure (if not exact) when joining elbow fittings.
Pro tip 2: If you are connecting PVC nipples to an irrigation system, be sure to check the pipe manufacturer’s instructions. It may require only a half turn or a full turn of the finger to tighten the connection.
Frequent questions
Why should you thread PVC pipes?
Threading can help prevent damage along miles of plastic piping. This is especially important for pipes that are subjected to higher pressures (100 pounds per square inch/PSI or more.)
Because threaded connections make pipes durable and leak-proof, they are best used in sprinklers and other related plumbing projects.
What causes a PVC threaded connection to fail?
Although a threaded PVC joint program will help prevent a leak path, they can occur for the following reasons:
- Excessive tightening. Turning the fitting more than once or twice will cause the female threads to break stretch out. System pressure stress can affect the tensile strength of PVC. As a result, the sharp edges of the threads will break.
- Applying the wrong sealant. Some products contain oils and solvents that can damage the plastic.
How do you find the right sealant for threaded PVC pipes?
First, you need to check and evaluate the brands of pipe sealant. Make sure the sealant is compatible with PVC pipes. If it is designed for a metal pipe, it will not seal the plastic threads properly.
Can I use teflon paste or pipe plug on threaded PVC pipes?
No, because they are more suitable for metal pipes – not plastic ones.
Although both are quality materials, they can make joints slippery. This can lead to you over-tightening the pipes, which could then lead to a leaky connection.
Can I use Schedule 80 fittings with a Schedule 40 system?
Not. If you are using an 80 schedule then you should thread with the same pipe fitting. The same goes for a 40 program pipe.
Using incompatible fittings may result in over-tightening. Just because it’s schedule 80 doesn’t mean you have to tighten it up. Although its walls are thicker, the deformation levels and strength of PVC remain the same.
Fun fact: According to this articleinserting a nipple wire into an incompatible system will end up reducing its efficiency by as much as 50%. This will make the system weaker, so keep the fittings compatible!
Conclusion
To thread a PVC pipe, you must first clamp the pipe in the vise. Next, place the tapered shaft before threading the pipe. You can do this by turning the cutter clockwise until the die is in line with the end of the pipe.
When connecting threaded PVC pipes, it is important to apply Teflon tape or sealant first. This will «seal» the leaky areas along the wires.
Threading PVC pipes is possible, isn’t it? But in case you have more questions about this process, feel free to post a comment below!
