How To Use Solvent Cement To Connect PVC Pipes And Fittings

In this plumbing guide, learn about how to use solvent cement to connect PVC pipes and fittings. Understand the full process of solvent welding to join PVC pipes together.

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The Basics of Connecting Pipes

PVC stands for polyvinyl chloride, which is a synthetic plastic material. A PVC pipe is most commonly used for water piping and distribution within plumbing systems. They're popular for their flexibility and strength, and can even be used for insulation. 

You can learn more about different pipe materials, piping tools, and more below:

• Pipes & Tubes - Types, Materials & Measurements

• Key Piping Tools - Pliers, Wrenches & Threaders

• The Best Guide to Trimming Pipes & Tubes

There are many ways to connect PVC pipes and fittings specifically, which are commonly used for water piping. This guide will cover solvent welding using PVC cement. Depending on the resources and materials available to you, using PVC cement to connect PVC pipes is often the easiest method.

Solvent Welding

Solvent welding uses an adhesive called solvent cement (sometimes referred to as PVC cement or pipe glue) to fuse pipes and fittings together. Note that this guide is specifically for PVC pipes used most notably for water piping. Different pipes may require different materials to be glued together. 

Materials Needed

• Pipes and fittings

• Solvent cement 

• Pipe cleaner

• Primer

• Pipe cutter or fine-toothed saw

• Sandpaper or file

Process

Ensure you are wearing the necessary safety equipment: gloves, goggles, and respirator masks. It's best that you're also in a ventilated environment. Then, begin with cutting your PVC pipes using a pipe cutter, handsaw or special plastic pipe cutter saws. It's important that your PVC pipes are cut SQUARE for the most snug connections. 

After cutting your PVC pipes, use a piece of sandpaper (medium-grade grit) or file to deburr both the inside and outside of your pipe. This should get rid of any rough edges and make the fitting process easier.

Align your pipe and fitting and ensure they're level. You can use a marker to remember where they align if needed. This process helps to make sure your pipe and fitting have no issues before applying solvent cement. 

Upon ensuring that your PVC pipes and fittings align, clean both with a pipe cleaner and rag. Next, apply primer for PVC pipes on the outside of your PVC pipes and inside of your fitting. Let your pipes and primer dry for 10-20 seconds.

You're now ready to apply solvent cement. Swipe an even layer of solvent cement on the inside of your fitting and the outside of your PVC pipe. For a strong joint, confirm that this layer is applied evenly and thoroughly.

To effectively "glue" the pipes together, you must act quickly so that the PVC cement does not dry. First, align the pipe and fitting one turn off of your original alignment - this ensures there's space to twist the pipes together while staying aligned in it's final position. Quickly push the PVC pipe into the fitting and twist until aligned. For a strong joint, keep the two pieces aligned for half a minute. 

Wipe off excess PVC cement on the outside of the PVC pipes and wait for the cement to cure to ensure they're properly glued together. The cure times for PVC cement depend on the temperature it's set in and the diameter of the PVC pipes. Make sure you DO NOT test these PVC pipes with compressed air or gas to avoid it bursting and shattering. These pipes are more suited for water piping, and using water to test can help to spot leaks. 

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FAQs

What is solvent welding?

Solvent welding is a method used to join plastic pipes, specifically PVC and CPVC, by applying a special solvent, often called PVC cement or PVC glue. This solvent softens the pipe surface, allowing it to fuse with a fitting, creating a strong and permanent connection.

What types of pipes can be joined using solvent welding?

Solvent welding is commonly used with PVC pipes, CPVC pipes, and fittings. These plastic materials are ideal for solvent welding due to their compatibility with the cement used in the process.

How do I connect PVC pipes using solvent welding?

To connect PVC pipes, follow these steps:

• Prepare the pipe: Use a pipe cutter to trim the pipe to the correct length.

• Clean the surfaces: Use a clean cloth or rag to wipe off any dust or debris from both the pipe and fitting.

• Apply PVC cement: Use a brush or applicator to apply a thin layer of PVC cement on both the pipe and the fitting. Be sure to use a consistent, even coat.

• Join the pipe and fitting: Insert the pipe into the fitting, giving it a slight twist to spread the cement evenly.

• Hold the connection: Press the pipe and fitting together for a few seconds to ensure a solid bond.

Can I use PVC cement on CPVC pipes?

Yes, but ensure that the cement you use is rated for both PVC and CPVC pipes. PVC and CPVC require slightly different adhesives, so be sure to choose the correct solvent for your specific pipe material.

Can solvent welding be used on other types of pipes, like metal or copper?

No, solvent welding is specifically designed for use with plastic pipes, such as PVC and CPVC. Metal pipes like copper require different joining techniques, such as threading, soldering, or using a coupling.

What types of fittings can I use with solvent welding?

Common fittings for solvent welding include tees, elbows, couplings, and reducers. These fittings can be used to make various types of connections, whether you’re working with straight lines or angled joints.

Can I use solvent welding for all types of pipe connections?

Solvent welding is ideal for PVC pipe and CPVC pipe connections, especially for simple, direct fittings. However, for more complex configurations or materials like galvanized steel or copper, you may need to consider other methods such as threaded connections or clamps.

Are there any special tools required for solvent welding?

While solvent welding doesn’t require much specialized equipment, having a pipe cutter and a PVC glue applicator can help ensure precise cuts and clean application of cement. A wrench may also be needed for tightening fittings in some cases, though this depends on the specific installation.

How long does it take for the joint to set?

Once you apply PVC cement and connect the pipe to the fitting, the bond typically sets within a few seconds. However, you should wait at least 15 minutes before handling the pipes, and 2 hours before pressurizing the system or using it for water or other fluids.

How do I ensure a leak-free connection?

To prevent leaks, it's essential to:

• Clean the pipe and fitting thoroughly before applying solvent.

• Apply enough PVC cement to ensure complete coverage of both the pipe and fitting surfaces.

• Press the joint together firmly for a few seconds to make sure the surfaces fuse correctly.

• Inspect the joint for any gaps or signs of improper application after curing.

What should I do if my pipe connection starts leaking?

If a leak develops at the joint, the pipe may need to be cut and rejoined. You can use a pipe cutter to remove the damaged section and repeat the solvent welding process with new pipe and fittings.

What happens if I use too much PVC cement?

Using too much PVC cement can lead to a messy connection, and excess cement may create weak spots at the joint that can cause leaks. It’s important to apply just enough to coat both the pipe and fitting evenly.

Can I use PVC glue for both the pipe and fitting?

Yes, PVC glue is the same as PVC cement and is used to bond the pipe to the fitting. Make sure to choose a high-quality glue that is designed for your specific application.

Can I solvent weld under water?

Solvent welding is not effective under water or in wet conditions. Always ensure the pipe and fitting are dry and clean before applying the cement for the best bond.

Do I need to prepare the pipe and fitting before solvent welding?

Yes, always clean and dry both the pipe and fitting before applying the cement. Deburring or sanding the edges of the pipe can also help ensure a better connection, especially for larger diameter pipes.

Can solvent welding be used for both small and large diameter pipes?

Yes, solvent welding works for both small and large diameter PVC and CPVC pipes. However, for larger pipes, you may need larger fittings and more cement to ensure a secure joint. It’s also important to use a proper pipe cutter to get clean, straight cuts, especially for larger diameter pipes.

What should I do if the PVC cement has dried out or is no longer usable?

If your PVC cement has dried out or become thick and unusable, it’s best to replace it with fresh cement. Old or dried-out cement can result in weak joints or failed connections, leading to potential leaks. Be sure to store your PVC cement in a cool, dry place to extend its shelf life.

Quiz

Question #1: What is the primary adhesive used in solvent welding for PVC pipes?

1. Epoxy resin

2. Solvent cement

3. Super glue

4. Silicone sealant

Question #2: What tool should be used to cut a PVC pipe?

1. Wood saw

2. Pipe cutter or fine-toothed saw

3. Hammer

4. Metal file

Question #3: What must you do to PVC pipes after cutting them to make the fitting process easier?

1. Apply solvent cement

2. Deburr the edges 

3. Heat the pipes

4. Paint the pipes

Question #4: True or false - You should align the pipe and fitting before applying PVC cement.

1. True

2. False

Question #5: What should be done immediately after applying solvent cement to the pipe and fitting?

1. Paint the pipe

2. Heat the pipe

3. Quickly push the pipe into the fitting and twist until aligned

4. Sand the pipe

Question #6: True or false - You should use compressed air and/or gas to test connected PVC pipe and fitting.

1. True

2. False