Need to seal PVC leak in a p-trap

Old 03-29-20, 07:35 PM
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Need to seal PVC leak in a p-trap

Greetings, is there some kind of putty-like material that can weld to PVC plastic, much like the cement, and make a permanent seal?

I have a p-trap for a shower between the joists of a 2nd floor. I tested the tightness and it seemed good enough to enclose. I tested for leaks and it was dry. Then while pressing the shower drain against it, it moved! Now there is some wetness around the edge of the p-trap's nut, but its in a place where I cannot tighten it further. A putty sealant would be ideal.
Old 03-29-20, 10:02 PM
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You might try joint compound on the threads but it still relies on a tight fitting.
Pro dope pipe joint compound
Old 03-30-20, 11:38 AM
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I don't think any sealant is going to work long-term without removing the nut first. I mean, you could use an epoxy like JB Weld, but it's not something I'd want to do on a new installation.

You said it's leaking from the P-trap nut. If the ceiling is going to be enclosed, you really should be using a cemented trap per code. And are you sure it's leaking from the trap nut as opposed to the drain itself? If the shower pan moves a bit, it's probably more likely the drain.
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Old 03-30-20, 12:52 PM
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I'm with Zorfdt. You should not be using a removable trap for a shower. If you don't have access now to tighten the nut you won't be able to remove it for cleaning so it's useless and a potential leak point. In an enclosed, not accessible location you need to use glued fittings.

The other option Zorfdt mentioned is the nut for the shower drain. If this is a plastic or fiberglass shower pan did you bed it in mortar? Plastic/fiberglass pans are notorious for cracking and leaking if there is any movement. That movement also causes the drain to leak where it attaches to the shower pan. You need to get all this worked out and bullet proof before enclosing the area as it will have to be opened back up to take care of any leaks in the future.
Old 03-30-20, 03:14 PM
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is there some kind of putty-like material that can weld to PVC plastic
Sure, it's the infomercial that comes on right after flex-seal.

Seriously, you want to do this right, no caulks, no glues, no putty.

Take everything apart clean and reassemble using teflon paste and do it right!
Old 03-30-20, 04:19 PM
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I think that you have the wrong style trap. I don't know if it is a code requirement but in my opinion a shower trap should be assembled with PVC cement not with a mechanical joint.
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