Pipe dope on main water lines?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Tammy Jones, Feb 16, 2020.

  1. Tammy Jones

    Tammy Jones New Member

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    Feb 16, 2020
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    Boston
    I have a leaking faucet ( please see the pic below ). It's slow drip that only occurs when the water is turned on. The faucet shown in the picture screws into a brass housing which is located behind the wall. I've tried tightening it up and adding Teflon tape, but doing both have not fixed the leak.

    Next, I'd like to use a combination of Teflon tape in combination pipe dope to stop the leak. However, since this faucet is connected to my main drinking water supply lines is it ok to use pipe dope on something like this? I'm concerned about these products leaching into my main water supply. The products I'm thinking about using are either RectorSeal #5 or RectorSeal T-Plus 2. Both these products are rated for potable water. Does that mean it's ok to use one something like my faucet, or do they need be rated as "food safe" as well? I'm confused on what the difference between "food safe" and "potable" products.

    IMG_5243.jpeg
     
  2. Reach4

    Reach4 Well-Known Member

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    Safe from that point of view. I am not sure of the nuances, but I think potable is used for water, and food is used for solids. Where would cooking oil fit in? I would think food too.

    That spout unscrews and screws in by rotating the spout? Does that spout have a tapered thread. You can lay it on a flat surface to see.
     
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  4. mliu

    mliu Active Member

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    What is the make and model of the faucet?

    Some of the plumbing fixtures sold online these days come from China and are made for the international market. Which means they have straight threads, not tapered threads (which are used in the US). Straight threads require a captured gasket for sealing. No amount of teflon tape and/or pipe dope will give a guaranteed leak-free connection with straight threads.
     
  5. mliu

    mliu Active Member

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    BTW, the two products you mentioned (RectorSeal #5 or RectorSeal T-Plus 2) are paste pipe sealants (colloquially referred to in the trade as "pipe dope"). They are not plumber's putty, which is something completely different and used for different purposes.

    Any thread sealant that is certified to NSF 61 standards for potable water is safe for the plumbing in your home. "Potable water" is drinking water. The difference between a product rated for "potable water" vs one that is rated "food grade" or "food safe" is that the former is approved for contact with drinking water, whereas the latter is approved for contact with food.

    For example, food grade or food safe grease is used on food processing machinery so that if a little grease falls into the food, it won't harm anyone nor adversely affect the quality of the food. Thread sealant that is rated for potable water is non-toxic when in contact with drinking water, but you wouldn't want it to fall into your food because, although it would still be non-toxic, it would adversely affect the quality of the food.
     
  6. Tammy Jones

    Tammy Jones New Member

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    @Reach4 and @mliu Thank you for your response and insights. They're much appreciated! You don't understand how much this helps

    > What is the make and model of the faucet?

    I don't know the name of the make and model, but the faucet does have straight threads and uses a rubber gasket as the seal. I have replaced the gasket and even added keg lube to the gasket to make a better seal. Unfortunately, that did not work.

    With all that said, I'm looking for any solution at this point. A solution that does not require tearing out the entire faucet and the brass housing parts behind the wall. This would be a rather large project that I unfortunately don't have the money to pay someone to do that at the moment. This is reason why I'm willing to give pipe dope ( not plumber's putty, haha ) in combination with Teflon tap a shot. Like you mentioned pipe dope isn't meant for straight thread pipes, but at this point I'm willing to try anything just to get the leak to stop for the indefinite future. It is a very small leak.

    Also, would you suggest RectorSeal #5 or RectorSeal T-Plus 2 one over the other for this application?
     
  7. mliu

    mliu Active Member

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    Feb 7, 2007
    Location:
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    Is the rubber gasket "captured" (have a ring of metal around the outer circumference to prevent the rubber from squishing out)? Photos of the disassembled fixture would help.

    First, forget the teflon tape; it won't help. Thread sealant may help, but I would only try that as a last resort (not now).

    I suspect your problem is either that the brass manifold behind the wall is set back too far so you're not compressing the gasket enough to get a good seal, and/or to maintain the correct downward orientation of the spout, you're not threading the facet on far enough to compress the gasket. Either way, the gasket is not sealing. It may also be that the gasket is damaged. Or the gasket is being over-compressed and either distorted or squeezed out-of-round, which will also allow it to leak. (Post photos of both sides of the gasket.)

    The problem is not just the water that you see leaking down the backsplash; the bigger problem is water that can be leaking inside the wall. That will lead to mold, fungus, wood rot, and probably termite infestation.

    Who installed this faucet and when? How long have you owned this and how long has it been leaking?
     
    Last edited: Feb 16, 2020
  8. Tammy Jones

    Tammy Jones New Member

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    I got some photos that should help. One of the problems that I'm having is that the rubber gasket is either too loose or too tight. This is due to this being an out-of-wall faucet. I either have to leave it a little loose or tighten it a full turn to get it pointing back down at the drain and sink.

    > Is the rubber gasket "captured" (have a ring of metal around the outer circumference to prevent the rubber from squishing out)? Photos of the disassembled fixture would help.

    Hopefully the pictures should help with this. From what you explained, it does not look like it is captured.

    > It may also be that the gasket is damaged. Or the gasket is being over-compressed and either distorted or squeezed out-of-round, which will also allow it to leak. (Post photos of both sides of the gasket.)

    Photos are below. And the gasket should be ok, it's brand new. I've tried several

    > Who installed this faucet and when? How long have you owned this and how long has it been leaking?

    Unfortunately I purchased the faucets then had a local plumber install them for me.

    NOTES: The goo you see on the attached faucet is keg lube to help seal the gasket. Adding keg lube to the gasket did not stop the leak. It leaks with it or without it.

    Again, thanks for the help. All advice is greatly appreciated.

    IMG_5247.jpg IMG_5248.jpg IMG_5245.jpeg IMG_5156.jpeg IMG_5250.jpg IMG_5249.jpg
     
  9. mliu

    mliu Active Member

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    First, that's an o-ring; you should be using a flat gasket. Besides captured gaskets, you could try one that's harder so it doesn't extrude. There are different thicknesses, so you may have to find one that gives adequate compression when the spout is rotated to the correct orientation.

    Do not use any lube because that just makes it easier for the rubber to extrude from the joint. The mating surfaces should be clean and dry.

    Speaking of mating surfaces, the metal faces that contact the gasket must be flat, smooth, and parallel without any scratches, dents, or gouges.
     
  10. Tammy Jones

    Tammy Jones New Member

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    @mliu Thank you for the advice and the clarification on the O-ring. The faucet came with the O-ring came with the faucet. It would be better to swap out this O-ring with a flat gasket with that said?
     
  11. mliu

    mliu Active Member

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    Yes.

    The gasket ID (hole) should be snug on the nipple, but not too tight. The OD should be as large or a little larger than the outer flange of the mating parts.
     
    Last edited: Feb 17, 2020
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The mating surface in the wall does not appear to be smooth. It looks like it has scratches and maybe a residue of pipe dope or plumber's putty on it. Cleaning that off without further dinging the surface may be a challenge. But, without that being smooth, making a good seal can be problematic.
     
  13. mliu

    mliu Active Member

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    Agreed. The mating surfaces can be smoothed with wet/dry fine grit (>180) emery paper backed by a block of flat hard wood. Do not sand back & forth, instead use a twisting/rotary motion (clockwise/counterclockwise).
     
  14. Tammy Jones

    Tammy Jones New Member

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    Feb 16, 2020
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    @mliu @jadnashua Thanks again for the continued help

    One thing I'm having a hard time finding is the flat washer rubber gaskets. Most of the places online have flat gaskets, but they're almost all nylon. I've checked Home Depot as well, with the same results. The only rubber ones that I'm finding have a inner hole that is way too small. Any advice on where to buy these rubber gaskets?
     
  15. Reach4

    Reach4 Well-Known Member

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    Is the thing the spout is being screwed into provided by the manufacturer, or is it a regular coupling not really meant to mate with that faucet?
     
  16. mliu

    mliu Active Member

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    What is the ID, OD, and thickness you're searching for?
     
  17. Tammy Jones

    Tammy Jones New Member

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    @mliu

    The ID is 3/4" and the OD is 1".

    I like the idea of sanding down the female end of the the pipe to smoothen it out a bit. Is there a concern of getting some fine brass particles ( from sanding ) getting inside of the female end of pipe, and thus entering my water supply? I plan on just shoving some paper towel in female end while I do the sanding. But even after cleaning up the area, there may be some very small and unseen brass particles that remain inside the female end of the pipe. And when I screw the faucet back on, those particles may enter my drinking supply. Is this a valid concern?
     
  18. mliu

    mliu Active Member

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    No. Simply turn on the faucet after you reassemble and the dust will get washed out. Debris won't travel upstream (against the flow of water) so it won't migrate to other parts of the house. Even if it did and you were to ingest a little, it won't hurt you.
     
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