How to Apply and Remove PVC Pipe Glue

A hand holding a piece of PVC after removing it from another piece. — It's the white plastic pipe commonly used for plumbing and drainage. PVC stands for polyvinyl chloride. Comstock / Getty Images

Whether you've made a mistake or you're replacing an old fixture, there are times you'll need to unglue Polyvinyl Chloride (PVC) pipe. However, this is impossible, as nothing will dissolve the solvent between the pieces of PVC [source: This Old House]. Fortunately, there is a solution when it comes to dealing with stubborn PVC pipe glue.

With the right tools and approach, you can "unglue" PVC pipe. The key is to follow these tips and know which method to avoid!

Contents

Understanding PVC Adhesives
Tools You'll Need to Glue PVC Pipe
How to "Unglue" and Glue PVC Pipes
Avoid the Heat Method
Tackle PVC Projects With Confidence

Understanding PVC Adhesives

Before delving into the process of ungluing PVC pipe, it’s important to understand the nature of PVC adhesives. PVC glue, also known as PVC cement, is a solvent-based adhesive that works by melting the surface of the PVC pipe and fitting. When the solvent evaporates, the two pieces of PVC fuse together, creating a bond that is often stronger than the pipe itself.

Tools You'll Need to Glue PVC Pipe

Here's what you'll need:

Hacksaw

A hacksaw is useful when you are unable to physically separate the glued PVC joint by heating and twisting. In such cases, you can use a hacksaw to carefully cut through the PVC pipe close to the joint. This allows you to remove the section of the pipe that is glued to the fitting. It's a practical tool for cutting PVC pipes with precision and control.

Purple Primer

Purple primer is used to clean and soften the PVC pipe's surface before applying PVC cement for reattachment. It helps in removing any dirt, oil, or ordinary adhesive remnants from the surface of the pipe, ensuring a clean area for the new adhesive.

The primer also softens the top layer of the PVC, which allows for a better bond when the new PVC cement is applied. Its purple color helps to visibly indicate the areas where it has been applied, ensuring comprehensive coverage.

Clear PVC Cement

After using the primer, clear PVC cement is applied to create a new bond between PVC pipes or fittings. This solvent cement works by chemically fusing the pieces of PVC together, creating a strong and reliable seal.

The clear PVC pipe cement is preferred in applications where aesthetic appearance matters, as it leaves no color residue on the pipe. Remember, not all universal solvent cements are created equal!

A New Fitting and Coupling

When a PVC pipe is cut to remove a glued joint, a new fitting and/or coupling may be necessary to reestablish the connection. The new fitting can be attached to the existing pipe using the PVC primer and cement. Couplings are especially useful when you need to connect two cut pipe ends together, providing a secure and leak-proof joint.

How to "Unglue" and Glue PVC Pipes

Here's what to do:

Cut out the problem joint Use a hacksaw to cut the PVC pipe flush along the fitting of the joint that you wish you could unglue [source: This Old House].
Get a new fitting and coupling Find a new fitting that satisfies your new needs. Find a coupling that matches the old fitting you didn't cut out and the new one you're adding.
Prime the PVC Apply a thin layer of purple primer to the ends of your PVC fittings. Also apply the primer to the inside of the coupling. Let the primer dry for a few minutes.
Glue the new joint together After the primer is dry, coat the primed areas of the pipes and coupling with clear PVC cement. Some multi-purpose cement glues aren't approved for all pipe uses, so make sure you're using a PVC-specific type. Push the pipe into the coupling while turning it a quarter turn. Make sure the fittings don't pop out before the adhesive hardens. If possible, wipe away any excess glue from the outside of the pipe before it dries.

Avoid the Heat Method

Using a heat gun or propane torch on PVC pipes poses significant risks due to the nature of PVC material and the high temperatures involved. PVC, when exposed to high heat, can release toxic fumes including chlorine gas and dioxins, which are harmful if inhaled and can cause respiratory problems, eye irritation, and other health issues. The risk is compounded in poorly ventilated areas where these fumes can accumulate.

Moreover, applying heat to PVC requires careful control; excessive heat can lead to the pipe melting or deforming, compromising its structural integrity and potentially causing leaks or breaks in the plumbing system. There's also a fire hazard to consider, as the high temperatures can ignite the PVC or nearby flammable materials. Always use safety goggles, avoid skin contact, and work in a well ventilated area.

Tackle PVC Projects With Confidence

Ungluing a PVC pipe is a challenging but achievable task. Once that's done, gluing PVC pipe in the fashion you want is a cinch!

By following these steps and taking necessary safety precautions, you can successfully separate and replace PVC joints in your plumbing projects. Remember, if you’re unsure about the process, it’s always best to consult with a professional plumber.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

PVC Pipe FAQ

Can you unglue PVC pipes?

You can use a purple primer to unglue it. For this, apply the primer and let it dry for a while. When itâ€™s dried, apply the PVC cement to the joints and couplings. Now, turn the pipe stealthily to stretch it out of its glued area. Another DIY way is to use a hair-dryer on a high heat setting to melt the glue. When given heat for a few minutes, the bond should break and fittings will pop out.

What is the preferred tool for cutting PVC pipe?

An easy and preferred tool to cut PVC pipe is a handsaw. You can use any saw for cutting, but a backsaw or hacksaw is an ideal tool with greater flexibility.

What glue works best on PVC pipe?

Using ordinary adhesives to join PVC pipes will not work. So, for a good fitting, Oatey glue is the best PVC glue. It has heavy-duty chemical solvents that provide leak-proof air-tight fittings. Moreover, it is specially formulated to melt the PVC surface for instant hardening to give added strength.

Can you use silicone to seal PVC pipe?

Yes, silicone is a fast and easy way to seal your PVC pipes. However, you should not apply silicone on a wet pipe. First, dry out your PVC pipes completely and then apply the silicone.

What can you use instead of a PVC glue?

If your application is not very demanding, you can use hot glue, contact cement or super glue as they also provide good adhesive strength to the PVC joints. However, they may not be reliable in the case of a pressurized water line that demands strong adhesion.