Slight indentation on bottom of new tub drain hole surface

[CharlieAZ]

Hi I am new to this forum and hoping that maybe someone had this issue and solved it before. We are in the middle of a bath remodel and we ordered an American Standard Studio tub (acrylic) because the old tub was an AS cast iron tub 60"x30" and we were trying to match the dimensions as the space is extremely tight. Unfortunately the drain hole is offset by an inch so that didn't work out either. In fact we had to notch out the studs to dry fit the new one in as they must have built the walls around the old one. While dry fitting the drain shoe I have noticed a defect in the surface area on the underside of the tub where the drain shoe gasket will seal. While the majority of the surface is smooth and flat, there are 2 indentations that I believe may cause a bad seal (see picture where you can see a small gap between seal and tub). I just have the seal loosely on there so I am not sure if I tightened it up if the rubber would seal that small dent up but I am afraid to install and find out it doesn't. So the first question is...has anyone had a similar defect and the rubber gasket conforms and sealed the small gap no problem? Or, is this an issue that needs to be fixed either by sanding or building up? I would assume it would be better to build it up so as to not weaken the thin acrylic drain lip area. I ordered an acrylic crack and chip repair kit from multitech to build it up and make if flat but wanted to see if there is any other advice out there for this situation like a thin piece of rubber in that spot? Thanks!

BTW I would just return the tub but it took weeks to get this one and no one has a replacement as they are backordered for months.

 

[Terry]

This may be a case for using some clear Silicone, bathtub grade.

 

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[WorthFlorida]

The rubber gasket seals as you tighten down the tub basket and it will bulge some. The rubber gaskets really doesn't seal water. It allows flex of the tub shoe as the weight of a person and water. Acrylic flexes a little more that a steel and cast iron. If you take a good look at this picture, it's the plumbers putty under flange of the tub basket or strainer that seals water from leaking down. The tub strainer threads inside the tub shoe so water cannot get under the tub from the threads. Should the plumbers putty ever fail a little water may weep down to the rubber gasket and it will prevent it from going any further.
Besure to use stainless plumbers putty. The installation instructions may read silicone rubber that can be used. You can put a little caulking between the rubber gasket and base if it makes you feel better.

https://terrylove.com/forums/index.php?threads/tub-drain-gasket-alternatives.85760/#post-616094

 

[CharlieAZ]

Thanks for the replies. I never thought of the gasket as a backup to the putty but it makes sense and I definitely should be good with the putty and using the acrylic build up kit to smooth the surface for the rubber gasket. (American Standard is paying for the acrylic kit so I figured I would try it) . Terry were you suggesting the silicone around the gasket to seal up the gap or in place of the putty?

 

[Terry]

I have always thought that is was the rubber washer between the tub and the shoe that does the sealing. HJ thinks that way too.
The putty under the flange doesn't really do anything. I like to install the rubber washer clean, though there was a time or two when that wasn't working, and I did use some Silicone on it.

New rubber washer installed clean, and a little putty under the flange inside the tub.

 

[Tuttles Revenge]

I'm of the opinion that the rubber between the tub and the shoe is the seal that keeps water from dripping out of the system/leaking.. The putty on the basket flange keeps water from draining past the stopper.

Most likely there is enough flat spot in the center to maintain a seal, but it couldn't hurt and I always add silicone to my rubber shoe washers because they're a PITA call back.

Tubs are my least favorite plumbing fixture to install, I've always hated them. The entire waste and overflow needs a 100% redesign