'Ungluing' pvc dwv pipe?

bmead144

bmead144

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Does anyone know of any product made to "unglue" solvent welded connections in pvc,cpvc & dwv pipes or if there even exists such a thing?Also whats the minimum horizontal drop/slope per foot for 3" dwv pipe?
 
The answer to taking PVC connections apart is in your question. These are not glued joints, they are solvent welded. The so-called glue causes the surfaces of the pipe and fitting to soften briefly, mix together, and when the solvent evaporates, the parts are fused together. There is no way to reverse the process, and at the price of fittings and pipe, it isn't worth the time and effort to try to do it anyway. All drains regardless of size or material require 1/4" per foot or more slope.
 
Which Code?

Minimum slope of 3" horizontal drain will depend on which code is enforced in your area.

The IPC and the IRC allow 1/8" per foot slope on 3" with 36 drainage fixture units or less.
 
I won't say BS to your device, but I will say I am highly doubtful that you can "unglue" a solvent welded PVC, ABS, or CPVC joint. The process of solvent welding melts the surfaces of both the pipe and the fitting and these mix or flow together when the joint is made and effectively make the weld.
 
hj said:
1/4" per foot is the minimum, there is no maximum.
Click to expand...
I am not a plumber but I did all my own plumbing when I built my house. ISTR the inspector mentioning that there was an ideal slope, that too much slope would separate the solid from the liquid. It might be a regional thing and/or fluid dynamics work different this far North.
 
The idea that the solids will get left behind is a widespread fairy tale, which all plumbing codes debunk.
 
Gluing PVC does not create any kind of weld. The above comment is true, there is a device that can "unglue" pvc and other plastic pipe. Here's a video of it working:
There's one for pipe up to 12" too.
 
Gary Swart said:
I won't say BS to your device, but I will say I am highly doubtful that you can "unglue" a solvent welded PVC, ABS, or CPVC joint. The process of solvent welding melts the surfaces of both the pipe and the fitting and these mix or flow together when the joint is made and effectively make the weld.
Click to expand...
 
Anyone seen a steel weld break due to someone using a crappy rod? Even a fusion weld (e.g. spot weld) can weaken the material around the weld, or a weld can be stronger than the surrounding material causing a failure point.

Having made the mistake of burying PVC directly in Texas clay and having "perfectly" primed and solvent welded joints cleanly pop makes me at least willing to question the "uniformly fused joint" idea...
 
I've taken quite a few pvc joints apart. I failed often early on, but it's doable most of the time. You've got "solvent welded" joints which are permanent when done right. Then you've got your "stuck pretty good" joints which can be peeled with a little know-how and a large amount of patience. The SPG joints seem to be more common. ABS is usually more difficult to peel. I am referring to dwv here. And forget CPVC.
 
I've taken apart both PVC and ABS fittings. It does depend on your access and what else is attached. I recently took two ABS trap adaptors off since they had developed small cracks. Depending upon if they are internal or external I used a hack saw blade to cut small sections one at a time parallel to the fitting about 1/4" apart and then use a 1/4" chisel or small screwdriver to pop out the section working my way around the pipe/fitting. Scrape the joint clean and sand a bit and you're ready to glue another fitting. It takes a bit of time but might be worth a shot if you are going to replace the pipe anyway. In my case the drain pipe was right against the wall with just the fitting exposed so I had no access.
 
As an expert plumber, I can provide some additional insights regarding the question.

There isn't a specific product designed to "unglue" solvent welded connections in PVC, CPVC, and DWV (drain-waste-vent) pipes. Solvent welding creates a strong and permanent bond between the pipes, and reversing this process is challenging. However, there are a few alternatives you can try:

  1. Heat application: Applying heat to the glued joint can soften the adhesive, making it easier to separate the pipes. Use a heat gun or a hairdryer on a low heat setting to warm the joint. Be cautious not to overheat or damage the pipes.
  2. Mechanical force: After heating the joint, try twisting and pulling the pipes apart using pliers, a wrench, or a similar tool. Apply gradual and controlled force to avoid damaging the pipes.
  3. Cutting the joint: If separating the pipes is necessary, you may need to cut the joint. Use a fine-tooth saw or a pipe cutter to carefully cut through the glued connection. This method requires replacing the section of pipe afterward.
Regarding the minimum horizontal drop or slope per foot for 3" DWV pipe, the recommended minimum slope is typically 1/4 inch per foot. This slope allows for proper drainage by maintaining a sufficient velocity to carry waste materials through the pipe. While there isn't a maximum slope, it's important to consider local plumbing codes and guidelines to ensure proper installation.

Please note that these recommendations are general guidelines, and it's always advisable to consult with a professional plumber who can assess the specific situation and provide expert advice tailored to your needs.
 
Ive got tools for that too, a saw , a mapp torch, hammer ,screwdriver and pliars. or a ram bit and drill motor
 
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