Under Sink Drain Leak

[JStelly]

We have a very small leak (a drop every time there is water in the sink) in the black drain pipe under the sink. Short of hand tightening it too much [emoji15]. what is the best way to stop the leak? What is the best sealant for black threaded pvc?

We are on the road headed to Custer SP. I know there is a HW store in Custer if I need to get something.

[davidmurphy02]

Originally Posted by JStelly

We have a very small leak (a drop every time there is water in the sink) in the black drain pipe under the sink. Short of hand tightening it too much [emoji15]. what is the best way to stop the leak? What is the best sealant for black threaded pvc?

We are on the road headed to Custer SP. I know there is a HW store in Custer if I need to get something.

Unless you are a real iron man you probably can't tighten too much to break it just with your hand - I would for sure try that first. Things have a way of working loose over the miles bouncing down the road, pretty common. Are you sure the leak is at the joint? If hand tightening doesn't fix it try drying it off with a paper towel and then running more water to see exactly where the leak is coming from - most likely just a loose joint but you never know.

[cpaharley2008]

For a band aid fix, place a dishpan under the sink area to catching drips until you can fix it right....

[JStelly]

Thanks guys. A pan is under the sink temporarily. I hand tightened it and will watch for more leaks. I can see where it’s leaking through the threads right behind the collar nut.

When googling the experts say no Teflon tape and no plumbers putty. A PVC expert wrote a long article explaining the qualities of a good sealer (soft and flexible and not too slippery) but didn’t give any commercially available products. [emoji35].

[Fender]

This is a plumber's version of putting on a bandaid but I've used it before and it worked well. Also removes easily. Doesn't really fix the problem but if you're traveling it may work as a good temporary fix. Available at most hardware stores.

https://www.canadiantire.ca/en/pdp/f...w.ds#store=337

[MVA]

If I understand correctly, your leak is at the base of the sink drain basket where it mates to the drain pipe ("collar nut"). The standard seals used on homes and RVs are a hard poly washer (translucent white). They do not seal well when the drain pipes are not perfectly aligned. I have used polypropylene seals in this instance:

https://www.homedepot.com/p/Everbilt...195C/205153791

HD also sells the conical washer seals made of the same material under the Everbilt name.

They are flexible and seal well.

[hugh]

Sometimes it's worth trying a replacement washer. That's worked for me many times over the years. It seems some are just prone to leaking after some time Maybe debris creeps in, and tightening just grinds deformities into the washer?

[JStelly]

A quick update. I tightened the collar nut about 1/4 inch and it stopped the leak. I’m going to watch it carefully. We have another 3 weeks to go on our trip. I’ll look at a permanent fix when we return if necessary.

Thanks for all the input.

John