[tkb289]

This may be a bit 'old school' but try pipe dope. It comes in a stick, looks like a fat crayon. Make sure both parts are clean and dry. Just rub it on the threads of the male part, till the threads are full then assemble and wipe off the excess. If you can, wait a day or so to let it firm up. Plumbers use this all of the time and it's rated for a variety of liquids and temperatures, usually listed on the label ... and it is also removable.

- Tim