I consider myself a pretty handy guy, but I can't figure out what I'm doing
wrong. Over the past couple years, I've replaced 3 sink strainers in
stainless steel sinks, a drain in a bathroom sink, and am now trying to
replace the drain in my bathtub.

I have the recurring problem of leaks - due to the plumber's putty around
the flange on the top side of the drains. I've tried using a lot of putty,
i've tried a little putty. I've tried as tight as I can turn, and I've
tried just snug. They drip about a dozen times before I get them right. I
use all the correct washers on the underside.

What am I doing right? What am I doing wrong? I've heard of using silicon
instead of putty. Should I go this route? I need to be sure I get the
bathroom leak fixed because a new drywall ceiling is going to cover it when
finished.

Greg