Jag Man wrote:

"Speedy Jim" wrote in message
...

Leaking at the putty should *not* cause a drip below.
That will only allow water in the basin to go down the
drain.

The secret is to seal the rubber Mack gasket to the
threads of the pop-up drain and also to the basin.
I use silicone sealant. Apply to top surface of the
Mack gasket and also liberally to the threads.
If you don't seal the threads, water will spiral
down them.

Jim


But Jim, where would the water spiraling down those threads come from?
Seems to me it can only come from the basin, 'cuz that's where the
water is, and if you follow the threads upward
you come right to that joint between the metal of the drain meets the
porcelain of the
basin, i.e., where the putty is. Conversley, if that joint is sealed
by the putty
AND THE DRAIN PLUG IS DOWN there is no way water can get to those
threads.
That's the test I'm talking about. I dry everything, close the plug,
and fill the sink up about 3-4".
After a bit the threads beneath the nut are wet. Not much, but wet
nonetheless.

Now, I agree that if the drain plug is up (or the basin is full and
flowing into the
overflow hole) the rubber Mack gasket (didn't know that's what it's
called) can
be involved.

I'm no plumber, but that's what I see when I look at the drain
plumbing.

Ed


You're correct; if the putty seals perfectly and the pop-up seals
perfectly, then water can not (should not) leak at the nut.

But somehow, some small amount is getting past one of those
2 places and if the threads aren't sealed to the gasket,
it will drip below.

I don't know the exact answer to your situation,
but if it drips below, it's not completely sealed.

Jim