Replacing tub waste elbow

[phantom]

I'm replacing the waste elbow under my bathtub. Should I use plumber's putty under the plug assembly inside the tub (and squeeze it out as I thread it on) or should I use some other sealant?
Also, should I use sealant on top of the rubber gasket that gets installed under the tub?

[LazyPup]

You have it correct.

the rubber gasket goes on the underside between the waste arm and the underside of the tub.

place plumbers putty on the underside of the tub basket flange, pass it down through the tub, the gasket and screw it into the waste arm receiver.

The best method is to use a tub basket wrench to tighten the tub basket into place, then wipe out the excess plumbers putty that pushes out from under the flange with a wet rag.

Some people elect to use a bit of clear silicone caulking on the rubber gasket but it is really not necessary and could make changing a gasket difficult in future.