Leak from new vanity sink! Help!

Hi folks-
As part of a bathroom remodel I've been working on this week, I replaced the tattered old vanity and lav sink. The new sink is a solid surface one from American Classics. Very nice. I've installed a Moen two-handle lavatory faucet (from the model 84000 series) into it.
There are actually two problems. The one that's bugging me the most is this:
The drain leaks a bit underneath, from where the drain bottom gasket meets the solid surface drain hole. I've carefully made sure that the bottom gasket is centered in the mounting washer, which has a little lip around it to hold the gasket. I've screwed it in with the mounting nut, and have it "pretty tight." I've got plumbers putty as directed under the drain seat. Nonetheless, a very slow drip happens (where the gasket meets the bottom of the bowl/drain opening) when something like a sink- bowl full of water is put down the drain.
Without a torque wrench and specifications, I'm not sure how tight is "too tight" for tightening the mounting nut. I'm trying to avoid cracking the solid surface material (the previous sink there had awful crazed cracks at the drain).
When I fit the pieces together, it seemed to me that the bottom gasket, which is conical, seemed just a little bit too big for the drain hole. In other words, the small end of the gasket, that mates with the drain hole, was just about exactly the same size as the drain hole. I would have expected it to be a bit smaller, so that some of the gasket would stick into the drain hole, to form a great seal.
Any ideas about how to deal with this?
The other problem is that the drain position doesn't quite match up with the drain position from the old sink, so the trap position is a bit off. I got a white plastic "flexible tube thing" that mates with the drain tube via a compression fitting. I think (not sure) that the compression fitting isn't totally secure; the sideways pressure the not-so-very- flexible tube puts on it I think makes it non-optimal. Any tricks? I may have this sorted out; with the drain opening leak dripping onto the fitting, it's hard to tell.
Thanks in advance.
Marc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
MAG wrote:

Take the drain fitting out, dry it off completely and apply a small amount of sealant (silicone caulk) to the rubber Mack washer and also to the threads. The sealant will prevent leaks between the sink bottom and the nut and also prevents water from running down the threads.
Offset on the trap center can be corrected by using a longer trap arm and swiveling the "J" bend to suit.
Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
SpeedyJim-
Thanks. I did as you suggested, and dried the parts, applied some clear silicone, reassembled, and let set overnight. Seems to have stopped the leak.
Thanks again!
Marc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.