Teflon tape, thread sealant, or PTFE paste for male PVC threads?

[Miami Reef]

I am trying to water seal the return lines which will use male PVC threaded elbows in the overflow box.

It needs to be water tight, as it will prevent water from leaking during a power outage.

Which should I use to get a water tight seal on scheduled 80 PVC?

 

[Harpo]

I have always used teflon tape and it has served me well

 

[CasperOe]

Teflon tape has worked very well for me as well, although some swear to Loctite as well.

The Loctite one will never come apart though!

 

[areefer01]

You are going to get a lot of different replies I believe on this one. I'm not a plumber but I never really liked the idea of using teflon tape. I believe when it is used properly it works, and works well. However my hangup was that I didn't want to add something that was going to alter the threads and thickness. So to me it made more sense to use Oatey great white pipe joint compound.

Again I'm not a plumber but just how I go about my work as a hobbyist.

 

[hart24601]

I use non hardening thread paste, at one point this is what manufacturers recommended for pvc vs Teflon tape due to tape interference with tolerances, but maybe that has changed but aside from being messy the stuff works great. Still have a little tub from maybe 15 years ago I have used on every salt and freshwater plumbing tank and I can’t think of any time it has had a leak.

RectorSeal T Plus 2 in. 4 oz. Teflon Pipe-Thread Putty/Sealant 23633 - The Home Depot

RectorSeal T Plus 2 pipe thread sealants are a non-setting, multi-purpose compound which contains PTFE, plus synthetic fibers to create a stronger seal. Recommended for use on threaded galvanized steel,

www.homedepot.com

 

[Mr Hughes]

I used blue monster pipe dope and it’s worked very well thus far.

 

[EricR]

The taper on PVC threads is supposed to seal on its own with no additional sealant.
That said, I use Teflon tape anyway even though I think that's considered poor practice from a plumber's perspective due to it messing with the tolerances of the threads.

I've only ever used pipe dope (paste) on metal but pretty sure at least some are intended for PVC as well.

*above assumes you want to be able to disassemble in the future,,, if not, glue/solvent for PVC might be best

 

[rennjidk]

Tape is not a sealent, and NPT fittings cannot make a true mechanical seal due to the taper of the threads. Tape is used as lubrication and does not bind to the threads like actual thread sealants. It's used in conjunction with a thread sealent in order to achieve a tighter joint when using metal connections such as black pipe for gas lines. Even with large wrenches, it can be difficult to fully seat the connection as metal threads cut into each other and deform. This is why black pipe is not reusable unless you cut new threads. Use some form of pipe dope that will bond to the surface and create a true seal.

 

[Miami Reef]

I use non hardening thread paste, at one point this is what manufacturers recommended for pvc vs Teflon tape due to tape interference with tolerances, but maybe that has changed but aside from being messy the stuff works great. Still have a little tub from maybe 15 years ago I have used on every salt and freshwater plumbing tank and I can’t think of any time it has had a leak.

RectorSeal T Plus 2 in. 4 oz. Teflon Pipe-Thread Putty/Sealant 23633 - The Home Depot

RectorSeal T Plus 2 pipe thread sealants are a non-setting, multi-purpose compound which contains PTFE, plus synthetic fibers to create a stronger seal. Recommended for use on threaded galvanized steel,

www.homedepot.com

Does this physically bind the PVC together? I NEED to be able to take the PVC apart for cleaning/maintenance.

Is there a dry time?

 

[Mr Hughes]

Does this physically bind the PVC together? I NEED to be able to take the PVC apart for cleaning/maintenance.

Is there a dry time?

It doesn’t bind the pvc like pvc cement does. Stays flexible and creates a better seal than thread tape. Because it stays flexible, there is no cure time, at least for the blue monster brand I used.

 

[BeanAnimal]

The taper on PVC threads is supposed to seal on its own with no additional sealant.

Not really. PVC to PVC threads generate quite a lot of friction when they are even slightly mismatched and become frozen.

The taper helps sealing, but tape or paste must be used. High quality fittings have high quality threads and seal much more easily.

 

[BeanAnimal]

Does this physically bind the PVC together? I NEED to be able to take the PVC apart for cleaning/maintenance.

Is there a dry time?

It is the proper product. It does not dry, it is just Teflon paste.

 

[Miami Reef]

I use non hardening thread paste, at one point this is what manufacturers recommended for pvc vs Teflon tape due to tape interference with tolerances, but maybe that has changed but aside from being messy the stuff works great. Still have a little tub from maybe 15 years ago I have used on every salt and freshwater plumbing tank and I can’t think of any time it has had a leak.

RectorSeal T Plus 2 in. 4 oz. Teflon Pipe-Thread Putty/Sealant 23633 - The Home Depot

RectorSeal T Plus 2 pipe thread sealants are a non-setting, multi-purpose compound which contains PTFE, plus synthetic fibers to create a stronger seal. Recommended for use on threaded galvanized steel,

www.homedepot.com

This is what I’m going to do. Thanks guys

 

[EeyoreIsMySpiritAnimal]

Does this physically bind the PVC together? I NEED to be able to take the PVC apart for cleaning/maintenance.

Is there a dry time?

It stays "rubbery" (but not tacky) and the purpose is to allow the joint/connection to be taken apart when needed. You might end up removing the old paste and adding new when you put things back together, just to be sure the new seal has full integrity but other than that it's pretty straightforward. I use the stuff in a tube since it's easier for me to control the amount but the can is more economical if you're going to use a lot (it doesn't take much though). When you twist the pieces together, some will likely be squeezed out and you can leave it or wipe it off... doesn't hurt anything either way and makes no difference in the ability to take the PVC apart.

 

[mfinn]

I use

La-Co-11775 LA-CO Plasto-Joint Stik Plastic Thread Sealant Stick​

I use to use tape for years. Never had an issue, until one time taking a pump out of service to do a cleaning.
put it back together the way it was for several years. But I guess I must have put one too many wraps of tape on it, because during the night the threaded fitting split and since it was on the pressure side of the pump it sprayed about 80 gallons of water out on the dining room, kitchen and half the living room rug.
Never again. Take my chances with a paste product.

 

[PR_nano]

I use

La-Co-11775 LA-CO Plasto-Joint Stik Plastic Thread Sealant Stick​

This is what I bought after small leaks and asking here/ doing research. Expect it today and can’t wait…

 

[edd59]

ues liquid teflon. its worked well for me on hyd fittings and water.

 

[EeyoreIsMySpiritAnimal]

I use

La-Co-11775 LA-CO Plasto-Joint Stik Plastic Thread Sealant Stick​

I use to use tape for years. Never had an issue, until one time taking a pump out of service to do a cleaning.
put it back together the way it was for several years. But I guess I must have put one too many wraps of tape on it, because during the night the threaded fitting split and since it was on the pressure side of the pump it sprayed about 80 gallons of water out on the dining room, kitchen and half the living room rug.
Never again. Take my chances with a paste product.

The sticks are good too!

 

[mfinn]

The sticks are good too!

Less messy with me.

 

[Red_Beard]

I use

La-Co-11775 LA-CO Plasto-Joint Stik Plastic Thread Sealant Stick​

I use to use tape for years. Never had an issue, until one time taking a pump out of service to do a cleaning.
put it back together the way it was for several years. But I guess I must have put one too many wraps of tape on it, because during the night the threaded fitting split and since it was on the pressure side of the pump it sprayed about 80 gallons of water out on the dining room, kitchen and half the living room rug.
Never again. Take my chances with a paste product.

Good call.
The problem isnt the added thickness, it is as was mentioned above (unless you add way more than the 3 wraps usually called out). Tape adds lubrication and makes people overtighten plastic fittings without realizing it. That is why they dont recomment ptfe tape on pvc threads, not because it wont seal or messes with thread dimensions, but because it changes the torque required to get a seal and also keep it.