Van Chocstraw wrote in
:

Oren wrote:
On Tue, 29 Dec 2009 17:22:38 -0600, wrote:

gwandsh wrote:
Hi all

I recently installed a new bathroom vanity, sink and faucet. I am
getting a small leak at the point where the large nut tightens the
drain assembly onto the bottom of the sink, compressing the black
washer onto the bottom of the sink drain.

I have seen sink installs before, checked the net for hints, and
even did a couple quite some time ago. I double checked the
sink/vanity that was removed from the space, and also on line, so I
know the washers on the drain assembly are in the right order. The
drain flange has a good ring of plumbers putty under it.

The sink itself is an ornamental handpainted model, and may have
some slight irregularities at the sink drain. Because the sink is
somewhat more delicate than the standard white porcelain models, I
don't want to risk overtightening the nut.

So what I am hoping to get are pointers on what the plumber-savvy
folks would do to handle a leak on the underside of the sink drain?
Can I add a thin bead of plumbers putty where the black washer
meets the sink, in an attempt to fill any irregularities the washer
can't handle? I am reluctant to use silicone at that point, just
in case it isn't successful and I have to dismantle it again.

Thanks for any tips


Drain pipes have been a problem for me as well. What I have
found is
that you need to tighten the connections as little as possible at
first.
If they leak, then tighten them some more. Over tightening them
does
not stop a leak like working with steel pipe.

One rule I follow when mounting a drain tail pipe in a sink. ALWAYS,
make the putty donut thicker/larger than needed. Mine may be 3/8 -
1/2 inch thick. When the nut is tightened below the excess putty is
squeezed from around the drain edge ( easy clean).

To little putty will possibly cause a leak along the tail pipe and
travel under the sink.

First guess? Pull the pipe and try again.

You shouldn't need any putty at all on a sink like that. The gasket
with the hump goes up against the sink and pipe and plugs the hole
around the drain when you tighten the nut. No putty needed if you did
it properly. If the OP has leaks then it should be taken off and
examined, not gooped up with putty and silicone. Replace the drain
pipe, gasket, nut as necessary. Make sure the sink isn't defective or
irregular around the drain hole. If so sand or file it smooth or
replace the sink too.



not gooped up with putty and silicone

Agree 100%. Sometimes we just don't follow the rules.