CPVC vs. PVC Glue: Which One Should I Use?

Perhaps you’re working through a plumbing project, trying to shorten your seemingly endless to-do list. However, once you gather your tools and materials to complete the job, you realize you don’t have the correct glue. You might be working with PVC but only have CPVC glue (or vice versa). So, do you need to take the time to go pick up the correct glue?

Key Points:

  • PVC and CPVC are two different types of pipe materials that require specialized glues for a reliable fit.
  • CPVC is designed for higher temperature levels than PVC, so its glue can easily be used for both material types.
  • Using CPVC glue on PVC pipes is safe, but not the other way around, as it can lead to compromised joints.

Or, maybe you’re at your local home improvement store, trying to determine what type of glue you need. After all, there’s only one extra letter in CPVC, so they’re practically the same, right? Not quite. This article reviews CPVC vs. PVC, which glue you should use, and the interchangeability of the two, so stick around to learn more!

Are PVC And CPVC The Same?

Christy's Red Hot Blue Glue PVC Cement - Medium Body, Very Fast Set, Low-VOC, 1/2 Pint (8 fl oz)

Polyvinyl chloride, also known as PVC, is a commonly used material in plumbing systems. CPVC, also known as chlorinated polyvinyl chloride, is also a standard material in plumbing systems, often used for hot water supply lines.

While the names are remarkably close, these two materials are entirely different. Since the names are so similar, many folks assume PVC and CPVC are interchangeable. However, this isn’t true, as each has its unique traits.

For example, one notable difference lies in the color of the piping. PVC comes standard in white, whereas CPVC features one of three colors: off-white, gray, or yellow. Of course, this is a minor difference, but it helps with easy identification.

The most significant differences lie within the composition and construction of these materials. With PVC, manufacturers use the nominal pipe size (NPS) system, which gauges the thickness of the pipe’s walls.

On the flip side, CPVC often uses the copper tubing size (CTS) scale, although it can be measured with the NPS system. However, while CPVC can be measured with either, the CTS scale isn’t compatible with the NPS system.

While CPVC and PVC are both thermoplastics, CPVC is altered by a free radical chlorination reaction, while PVC skips this step. This reaction increases the chlorine content of the pipe, making it different from its cousin. Its composition makes it more resistant to damage from domestic water sources with a high chlorine content, making it suitable for situations where PVC won’t work.

In addition to these differences, it’s important to note that CPVC can tolerate much higher temperatures than PVC. PVC can only withstand temperatures up to 140 degrees Fahrenheit. CPVC, on the other hand, is sufficient for up to 200 degrees Fahrenheit, making it the better choice for hot water lines.

Are PVC And CPVC Glue The Same?

Like the materials themselves, PVC and CPVC glue aren’t the same things, so you can’t use them interchangeably. These two piping materials have different compositions, so the glue used to join pipes varies.

CPVC glue is quite different from PVC glue, as it softens upon contact with CPVC. This enables the solvent to seep into tiny gaps and holes between the pipe sections, forming a secure, watertight bond.

On the other hand, PVC glue doesn’t perform like CPVC glue, which essentially fuses the pipes together. Instead, it works with different chemicals to achieve a similar goal. While CPVC glue creates a weld-like finish, PVC glue doesn’t “melt” to create the bond. While it’s a robust and durable option for PVC pipes, it’s designed for exactly that, so it isn’t sufficient for temperatures higher than 140 degrees Fahrenheit.

Is It OK To Use CPVC Glue On PVC?

Weld-On 10134 714 CPVC Heavy-Bodied High Strength Solvent Cement - Medium-Setting and Low-VOC, Gray, 1 Pint (16 fl oz)

Generally speaking, using CPVC glue for application on PVC pipe is okay, but not the other way around. As mentioned, CPVC pipe is designed to withstand higher temperatures than PVC. Because of this, CPVC glue must match the material’s heat resistance to withstand similar temperatures.

So, while you could use CPVC glue on PVC pipe since its temperature limit is higher than the material’s, you can’t flip it the other way. Using PVC glue on CPVC glue could result in compromised joints, so it’s essential to use the correct product based on the material you’re using.

So, Which Glue Should You Use: CPVC Or PVC?

Ideally, you should stick with the glue designed for the pipe you’re using. If you’re working with PVC pipes, use PVC glue. Or, if you’re joining CPVC pipes, enlist the help of CPVC glue. While there is some leeway with CPVC glue and PVC pipes, it’s best to stick with the correct glue for the pipe.

Can You Join PVC And CPVC?

So, if you can use CPVC glue on PVC, can you join PVC and CPVC? While the answer is technically yes, many plumbing professionals advise against doing this. Generally, there’s no reason to connect PVC to CPVC.

If you’re working with a plumbing line that can use PVC, it’s cheaper to stick with PVC the entire way through. While you could use CPVC where PVC would work, it’s more expensive to do this, so it’s usually better to stick with PVC. On the flip side, if you’re working with CPVC, it’s likely you’re working with a hot water line, so PVC isn’t an option.

That said, you can join the two if the situation calls for it. You’ll need to use the correct glue or adaptors to join the two materials, but it’s technically possible.

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