I notice that teak finishes often fail where the teak meets metal, because
water is able to infiltrate through the tiny unfinished cracks. It has been
suggested to me to apply a tiny bead of clear caulking on those edges, but I
think it would be difficult to achieve a satisfactory result (especially
with the five thumbs on my right hand.) I was wondering if an epoxy would
seal it up.

Also, I noticed one old post, where it was suggested that a thin epoxy coat
should be applied to the wood, before applying the finish. Is this a good
idea?

Thanks.