Good sealants for threaded PVC fittings? - brand names?

[Stephen Tashiro]

What are brand names of good sealants for threaded PVC pipe fittings?

According to https://www.lascofittings.com/threads, teflon tape and teflon based pipe dopes should not be used on PVC fittings due to risk of over tightening. Obviously any chemical that degrades PVC plastic should not be used. My favorite sealant, Hercules Block ( https://www.oatey.com/products/hercules-brushon-block-1618445780 ) is listed as "compatible" with PVC, but I don't know whether it contains teflon or another lubricant that risks over tightening.

[Tom M King]

Whatever you use doesn't make you overtighten a fitting. One rule of thumb I always use for threaded PVC fittings, that I never change from: Never use a female threaded PVC fitting for anything on supply lines.

The past several times someone has told me that their water lines developed a leak, I asked, "female threaded PVC adapter?" So far, the answer has always been, "yes."

If I need a female threaded adapter on PVC, I use a male threaded adapter, and a stainless, or brass coupling on that.

[Bruce Wrenn]

My theory on threaded PVC couplings is they are a ONE TIME ONLY connection. For lubricant' I use Oatley's GreatWhite."

[Kev Williams]

Just a thought, how about yellow gas line teflon tape and hand-tighten?

[Michael J Evans]

Hmm, I don't see why teflon tape or dope cant be used. Just don't over tighten. With PVC a little more than hand tight is all it takes.

[Andrew Seemann]

I have always used teflon tape, which usually works just fine. The main risk is cracking a female fitting as noted above. That risk comes from the fact that no matter how loose or tight the fitting is, it always seems to leak. In general I avoid female PVC fittings. Sometimes CPVC female fittings have an o-ring in them, which usually works well.

Male PVC into female metal fittings usually works, although not always. If at all possible, avoid any PVC fitting with threads; solvent weld is almost always more reliable for PVC.

[Michael J Evans]

When I deal with plastic fitting they are normally poly or nylon fittings, but they just get the standard procedure dope or tape.
For pneumatic applications we use "pneumatic/hydraulic" sealant, we have found that works best of anything for the most demanding applications. It is expensive but works very well. It comes from a company called MRO solutions, but I'm sure loctite makes something similar.

[Frank Pratt]

PVC pipe should NOT be used with compressed air.

[Stephen Tashiro]

If at all possible, avoid any PVC fitting with threads; solvent weld is almost always more reliable for PVC.

The immediate situation is at a friend's house where a new PVC clean-out under the kitchen sink was installed so it's behind the plane of the wall around it. We want to close-off the cavity that was excavated in the plaster and block wall during the drain repair, so we need to extend the clean-out beyond the face of the wall. It seems simplest to thread an extension into the clean-out.

[Bruce Wrenn]

The immediate situation is at a friend's house where a new PVC clean-out under the kitchen sink was installed so it's behind the plane of the wall around it. We want to close-off the cavity that was excavated in the plaster and block wall during the drain repair, so we need to extend the clean-out beyond the face of the wall. It seems simplest to thread an extension into the clean-out.If the clean out was solvent welded (glued in place) there are tools to remove fitting from the tee. For a one time use, the cheap (less than $20) one works.

[Mike Henderson]

If the clean out was solvent welded (glued in place) there are tools to remove fitting from the tee. For a one time use, the cheap (less than $20) one works.

That's new information to me, Bruce. I didn't know that was possible. Would you post a link to one of those tools, please?

Mike

[Bruce Wrenn]

That's new information to me, Bruce. I didn't know that was possible. Would you post a link to one of those tools, please?

Mike


Mike look on YouTube " removing a glued up PVC fitting." That' where I saw about this technique.

[Mike Henderson]

Mike look on YouTube " removing a glued up PVC fitting." That' where I saw about this technique.

I found this on Amazon (https://www.amazon.com/Reed-Tool-PPR150-Extreme-1-%C2%BD-Inch/dp/B005STKRC4/ref=sr_1_1?crid=2ZQZT4PCHDQBH&dchild=1&keywords=reed+tool+ppr150+clean+ream&qid=1602094562&sprefix=reed+tool+ppr150%2Caps%2C240&sr=8-1). I think it's the same as in the video.

Mike

[Stephen Tashiro]

I found this on Amazon (https://www.amazon.com/Reed-Tool-PPR150-Extreme-1-%C2%BD-Inch/dp/B005STKRC4/ref=sr_1_1?crid=2ZQZT4PCHDQBH&dchild=1&keywords=reed+tool+ppr150+clean+ream&qid=1602094562&sprefix=reed+tool+ppr150%2Caps%2C240&sr=8-1). I think it's the same as in the video.

Mike

and here's a video: https://www.youtube.com/watch?v=9dowLe-Bu3w

However, I'm not going to use that technique. Working in the cabinet underneath the kitchen sink and risking damage to a tee that the plumber installed inside the wall with great difficulty? - not on my first try at using a reamer. I'll stick with threading a connector into the existing clean-out.

[Tom M King]

I don't mind female threads in DWV pipe. I thought we were talking about supply lines. Almost anything will keep a DWV fitting from leaking.