How to seal vessel sink with overflow?

Ok, so here's my situation. I bought a Decolav stainless steel vessel sink (model# 1216) and the matching Decolav popup drain with overflow (model# 9297). All of this was brand new in unopened packaging. According to the instructions that came with the drain, all that's needed is a 1 3/4" hole on top of the counter, no mounting ring necessary. But the instructions show no seal for the overflow. There's a rubber washer that goes on the under side of the counter and that's it. The drain just slides into the bowl and doesn't create an airtight fit at all.

If I install this way, water will leak out the overflow and ruin the countertop where the hole was cut. Sure, it might not actually leak, but ruining the wood countertop isn't a very good design. So basically, there's nothing between the countertop and the bowl. It seems like even if I used the washer it shows to install on the underside of the countertop above it, it wouldn't create a tight fit on the drain either (it loosly slides over the drain), so doesn't seem like it would really help.

It really seems like I'm missing a washer or gasket or something, but all the parts listed on the drain and in instructions are there. Is there some sort of thin rubber gasket I can buy that can be attached to the drain between the bowl and countertop that will create a seal? Or is there something else I'm just stupidly missing? Or has anyone had experience with this sink/drain combo and have any advice? Like caulking around the drain and into the bowl to create a seal and if that will hold up?

Anyway, any help is appreciated. I'm dumbfounded as to why they'd do this.

Thanks,

-Josh

I'm not familiar with this model. Can you post a couple photos? Have you tried their 800 number for technical assistance?

here's some links

Here are links to the products on the Decolav site. They have PDFs of the installation instructions too, which highlight my issue fairly well.

Drain
http://www.decolav.com/details.asp?ProdID=89

Sink
http://www.decolav.com/details.asp?ProdID=60

I haven't called Decolav yet. It was too late today, so I'm going to try tomorrow.

Anyway, I'm hoping that a plumbing store may have a thin rubber gasket that I can put on the drain between the sink and the counter top that will solve the problem once it's all tightened up. I don't want anything too thick, since the sink would look kind of funny if it was raised off the countertop. The sink is pretty tall as it is (thankfully our vanity is a few inches shorter than a normal one, since we're repurposing a vintage piece of furniture)

sink

Obviously those instructions were written by someone who has never installed one of those drains and actually put water in the sink. Doing it that way, regardless of the countertop material, but it would have to be an impervious material, there is no "seal" between the sink and the countertop so water will leak out there. You do not use the countertop as part of the drain, EVER. The drain is mounted to the sink FIRST, and then the sink is secured to the countertop with the drain passing through the hole in it.

So...

Well, that's pretty much what I thought, too. I just don't know why they would design it this way.

So, I just called Decolav and it turns out there's supposed to be a tapered rubber gasket with it, even though it's not listed in the parts with the drain or on the instructions. That supposedly slides up in over the drain and into the sink, so when it's tightened down, creates the seal.

I'm still unconvinced that this is the best method, considering if someone pulls down on the sink while it's running, the seals could be comprimised and it could leak. Oh well, my wife and I don't have kids at this point, so we should be ok for a while.

I may look into cutting an extra circular channel into the countertop so I can attach another nut between the counter and the bowl where the nut will just set into, and the bowl will still sit flush against the countertop.