As two of the most common pipes used in plumbing, homeowners always have to deal with PVC and ABS plastic. In the trade, they are also referred to as “the white plastic” and “the black plastic”.
Depending on the type of system, plumbers prefer to use both types of plastic.
There are also many cases where both pipes are used in combination which is the topic of our discussion today.
Can you connect them? Yes, you can. But how to connect ABS to PVC plastic?
Since they are completely two different types of plastic, you can’t simply join them with glue. There are a few techniques to keep in mind if you want to don’t deal with leaks and broken water lines.
In this article, we’ll discuss two popular methods used in the plumbing industry. Keep on reading.
Best Methods to Connect ABS to PVC
Now, when it comes to connecting these two pipes, the consensus is that they can be connected properly together. But the only acceptable method to authorities and home inspectors is using mechanical coupling and fittings.
The other “unacceptable” and frowned upon method is gluing. In this method, a type of transition glue is used to connect them together. How strong is it? We’ll get into it later.
But why is the gluing method looked down upon when it has UPC approval? Well, according to ASTM standards, the transitioning glue in question is only approved for joining a drainage system to another drainage system.
It means that it’s approved for only a non-pressure system (where the pressure is 25 psi or less). People mistake the UPC approval for an all-purpose approval for using the glue all over the house.
Well, now you know why it’s not accepted officially. I used the word officially intentionally since the home inspectors can approve the use of this transitioning glue unofficially.
According to a home inspector from the State of Minnesota, the joining of ABS to PVC using the transitioning glue is strong enough to withstand the water pressure available in homes.
For everyone’s sake, I’ll share the detailed process of connecting ABS to PVC with both methods.
Connecting ABS to PVC Using Mechanical Coupling
To connect ABS to PVC pipes using fittings, you’re going to need a couple of tools and materials to get started.
Tools and Materials:
- Socket wrench
- Transition coupling
What’s a Transition Coupling?
These are also known as Specialty coupling. Transition coupling refers to a type of fittings used in plumbing. It consists of a cylindrical rubber gasket with an internal pipe stop and a metal shield covered with clamps.
It’s tightened with worm gear-style screws. It’s used to connect different types of pipes together in a straight line. Here’s a photo,
How to Connect ABS to PVC? Step-By-Step Guide
Step 1: Prepare and Position the Pipes
If you’re dealing with two fixed pipes, cut them in a way that leaves only a 1/8-inch gap between the pipes. Or, if the pipes are not fixed yet, install them by leaving the same 1/8-inch gap between the pipes. This gap will be filled up by the rubber gasket’s internal pipe stop.
Step 2: Slide in the Coupling
Take the transitional coupling and loosen the metal jacket clamps and take the rubber gasket out. Slide the metal jacket to either one of the pipes.
Roll the rubber gasket back and push it onto one of the pipes. Rollback the other end to make room for the second pipe. When in position, unroll the rubber gasket.
Next, slide the metal jacket over the gasket and tighten the clamp screws. Use the wrench to secure them in place.
You should be done. Test the joint by flowing water through it. Make necessary adjustments if needed.
Using Transitioning Glue
Before going further, I should mention that if you follow this method, follow it to your own accord. Not every home inspector will turn a blind eye to it. And if the pressure in the water supply line increases, there is a huge risk of leaks.
And it should be noted that you can’t glue two already fixed pipes together. You’ll need an extra piece of PVC or ABS pipe to connect them.
With that said and done, here are the things you’ll need to start working on.
- Transitioning glue (the glowy green one)
- PVC glue
- Black glue for ABS
- Primer (optional)
- An extra piece of ABS or PVC pipe (only if needed)
- A couple of ABS and PVC fittings
The purple-colored primer is necessary for cleaning and softening the plastic surface to ensure a good solvent weld. It’s generally used with PVC and optional for ABS. We won’t be using primer on the ABS to PVC connection.
We’ll use an extra ABS pipe as the connector between two fixed pipes. And tests show that ABS to ABS connection is practically indestructible.
But if you’re using an extra piece of PVC to connect them, you need to use primer when attaching PVC to PVC.
Now, follow the steps below:
• Step 1: Clean the Ends of the Pipes
First, take a clean and wet rag and clean the pipe ends to get rid of dirt and dust. It’ll help the transitioning glue, aka solvent-cement to weld well to the pipe surface.
Tap it dry with a paper towel.
• Step 2: Attach the Fittings
The fittings will first be attached in this way; PVC to PVC and ABS to ABS. Attaching the fitting is a straightforward process.
Apply Primer and PVC clear glue on the PVC pipe. Slide the fittings on with a twisting motion. It ensures a stronger joint.
For the ABS, no need to apply primer. Just apply the black glue and slide the ABS fitting in a similar fashion.
If you’re using an extra pipe, use ABS. Attach the extra pipe onto the fitting from the other end. The process is exactly the same. Here’s a video tutorial you can follow.
• Step 3: Attach the ABS to PVC
Now take the ABS pipe and apply transition glue to it. No need to put primer on it. Slide it into the PVC fitting with a twisting motion. And you’re done.
Tip: Ensure proper ventilation when attaching the pipes. You need sufficient airflow for the glue to activate and harden.
Frequently Asked Questions
1. Can you use all-purpose cement for ABS to PVC?
Yes, you can use the all-purpose cement to attach ABS to PVC pipes and fittings as long as the diameter is 6 inches or less. Check the label before purchasing.
2. Can I use ABS cement on PVC to PVC?
No, you can’t, and you shouldn’t. ABS black glue is only meant to be used to connect ABS to ABS material.
3. Does Gorilla Glue work on ABS plastic?
Yes, Gorilla Glue is one of the most tested glues that gets approval to work on all kinds of plastic including ABS plastic. The pipe diameter limit is 6 inches.
4. Can you use PVC primer on ABS?
No, you are not supposed to use primer on ABS. It’s explicitly mentioned in the can that it’s not to be used with ABS plastic.
Hopefully, the above guideline on how to connect ABS to PVC has been fruitful for you. Both the methods mentioned in the article have been used in plumbing.
Only the coupling method is approved by the authority. And it’s certainly the most secure way of connecting these two types of pipes.
If you’re confident that the water pressure in your home isn’t high enough to burst through the ABS-PVC glued joints, you can apply the second method.
I’d suggest inquiring with the local home inspector to ensure you don’t face any trouble later on.