Catnip nailed the answer (thankfully, saving me some typing ).
One quick tip, use teflon tape, the pipe dope and a rubber o-ring -- tape the threads, then put on one of the o-rings that comes on some threaded plugs (SP 1022-C-Z 1). With the 'tripple threat' the only thing that could still allow a leak is a crack or warpage of the threads.