# Threaded PVC fittings--Teflon tape needed?



## jbolinger (Oct 13, 2007)

Is teflon tape needed to seal a PVC to PVC threaded joint?

What about PVC to other types of plastic?

Is teflon bad for an aquarium?

Jim


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## kzr750r1 (Jun 8, 2004)

At times yes. No it's not detrimental to the aquarium.


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## imeridian (Jan 19, 2007)

Yes, any threaded water connection will benefit from teflon tape.


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## gsd78 (Jan 13, 2004)

Teflon paste is an option as well. I tend to prefer it over the tape.


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## Vonzorfox (Nov 22, 2007)

I second the yes as a past plumber.


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## swylie (May 10, 2007)

I use either teflon tape or some other kind of thread sealant or lubricant on almost any threaded joint I work with. Not only does teflon tape seal joints when you're doing plumbing, but it lubricates them. This makes it _so_ much easier to smoothly apply the correct torque to get a joint to the right tightness, and it makes it _so_ much easier to take joints apart.

Pipe dope will also seal joints as well as lubricate them. For some reason I don't like pipe dope and prefer teflon tape in all my work, but I admit that's just personal preference. Silicone grease is great as a lubricant, but it doesn't assist in sealing.

Teflon and silicone grease are both fish safe. Look at your can of pipe dope for whether it's suitable for potable water to determine if it's fish safe as well.


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## PDX-PLT (Feb 14, 2007)

If the joint is under house-water-type pressure (40+ psi), then yes you need a thread sealant. Teflon tape is recommended for plastics, most pipe dope sealants are not (metal only).

In low-pressure applications, you may get away without sealant.

PFTE (a.k.a. Teflon) is completely inert, unless you get it very hot (>500 degrees).


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## JSCOOK (Jan 7, 2008)

PDX-PLT said:


> Teflon tape is recommended for plastics, most pipe dope sealants are not (metal only).
> 
> 
> > All the pipe dope I have here at home and work state that they can be used on plastic as well as metal fittings ... most new stuff is.


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## PDX-PLT (Feb 14, 2007)

JSCOOK said:


> All the pipe dope I have here at home and work state that they can be used on plastic as well as metal fittings ... most new stuff is.


I'll have to look for some. I've had much better luck getting leak-free connections with pipe dope than the tape.


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## crazy loaches (Sep 29, 2006)

FWIW with water apps the pink teflon works better for me then the regular white stuff. Some folks dont realize teflon comes in anything but the regular white stuff (which is for air applications).


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## swylie (May 10, 2007)

crazy loaches said:


> FWIW with water apps the pink teflon works better for me then the regular white stuff. Some folks dont realize teflon comes in anything but the regular white stuff (which is for air applications).


As far as I remember, the only difference is the thickness. White is the thinnest, yellow is significantly thicker and is for gas pipes, and I dunno about pink. I'm almost positive you're mistaken about white tape being only for air applications.


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## crazy loaches (Sep 29, 2006)

Yeah, its thickness. White for air, yellow is thicker for gas, and pink is thickest for water.


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## imeridian (Jan 19, 2007)

Interesting, I've seen the pink stuff once (I think), but it's the white stuff that is plastered all over the Lowe's plumbing section. I did know that yellow was for gas though. Wouldn't it make more sense for them to promote the pink stuff, since it surely would be a higher ticket item, if it's the right one for the job?

Wouldn't just a few extra wraps make up for any thickness difference?

--
Okay, I figured it out. Pink is indeed the color coded higher density teflon for water use, but it isn't necessary to use pink for water connections. There's apparently green for Oxygen use, yellow is for gas, etc. The color code does apply to the thicker stuff, but not for 'standard thickness white' and for cases of oxygen or gas is required for that purpose, so as to ensure there's enough being applied. A couple extra wraps does suffice instead of using thicker teflon tape. The color doesn't indicate the thickness though, it's just a color code for application, the tape is either standard, high, or full density. So, unless it says otherwise, the pink tape is just as thick as the yellow tape, color doesn't necessarily differentiate them.


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## SPC (Jan 14, 2008)

I use GE silicone when I don't expect to take the parts apart very often.

Steve


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