Re: Transom drain plug.
... So what is Teflon tape good for? I've got a bunch of it.
The purpose of Teflon tape is to fill in the gaps between the threads in a fitting.
Even tapered thread do not completely seal when tightened.
It become the virtual gasket.
The alternative is Pipe Thread Seal paste.
It is messy and tends to dry out over time.
And not as acceptable if some of it gets into the flow stream if used on pipes carrying food stuffs. (Water, Milk, Beer)
Teflon tape is a one time use product.
Once you back off the threads, you will need to remove the remaining tape and reapply.
On a bilge plug it will make little difference.
A one ounce a day leak on a boat is nowhere near as noticeable as a one ounce leak under your sink!