drainagesink
I'm trying to install any new pop-up assembly because my sink is currently leaking from the gasket. I purchased a Ace Hardware brand replacement. Unfortunately, I did not read the directions before I left the hardware store.
Now, I am at home and I see that the instructions say to "apply plumbers putty to the rim of the hole"– to seal the flange into place.
So is it possible to use Teflon tape instead of plumbers putty for this?
It should not be necessary to try to goop some type of sealer around the lower neck of the sink drain. Such solution may work but it is not the desirable approach when you consider that someday this assembly will need to come apart for repairs.
In looking at the assembly that you have I wonder if one or more things are at play here.
1) If the drain pipe tail was not centered in the neck of the sink drain and then had lateral force on it due to the down stream goose neck trap it could be forcing the gasket open on one side. Check that there is no undue large amount of sideways pressure on the lower part of this pipe assembly.
2) It looks like the gasket directly contacts with the face of the capture nut around the drain pipe. It is possible that by tightening the capture nut that it is putting a twisting force on the gasket that may cause it to "fold away" from the sealing edge of the sink neck.
3) It is possible that there could be a small crack or pitted area on the sink neck that keeps the rubber gasket from engaging 100% with the sink neck.
4) Sometimes the "rubber" used in this type gasket is made of a plastic material that is anything but rubber. Check at the local hardware store to see if they have another gasket that is more pliable. In some cases a silicon material may be better.
There is no "right way", but the "theory" is:
On a loose fitting (fitting has play inside the hole), placing the putty on the sink will create a better seal on the area actually making contact. On a tighter fitting, placing the putty on the flange will seal the areas closer to the center leaving less room for voids. See this diagram (tight fitting on top, loose fitting on bottom, "risk" for voids/incomplete seal in red):
Honestly, while the "theory" isn't bad, in practice it simply requires that you use enough putty to make a good seal. The net effect is that the putty just needs to be sandwiched between the flange and the sink to prevent water from leaking, either from an (intentionally) stopped sink into the overflow (bathroom) and thus down the drain, or from around the flange into the cabinet below when the flange acts as a reducer or on sinks without overflows (kitchen).
So, whichever way works best for you is the "right way".
Edit: Updated diagram to reflect the proper amount of putty. Edit(2): Updated diagram to reflect proper amount of putty including over-puttying.
Best Answer
In a word, no. The plumber's putty is what forms the gasket between the drain insert and the bottom of the sink, and is likely what failed in the old one. Telfon tape doesn't work very well as a seal unless it is forced into an extremely tight space (i.e. on threads) and is really only made of Teflon to reduce friction enough to allow it to stay in place long enough to get the load on it tight enough.