Hey, Im wondering if metal mouthpieces can be refaced or repaired? Also, Ive heard of lots of mouthpieces being opened up but can you ever make the tip opening of a mouthpiece smaller?
Yes on both counts. If it's a stainless steel piece, it's extremely time consuming (thus expensive) to go much more than .005" on a tip opening adjustment (either more open or more closed).
Closing down the piece involves working the table, so one of the caveats is that if you have a specific ligature you like to use with a piece, the ligature may fit more loosely once the piece has been closed down. Something to consider with a ligature like a Vandoren Optimum or Francois Louis where they are not adjustable across a wide range of pieces (though slightly accomodating).
Of course, starting with a piece that is of similar design but a smaller facing can usually get you there as well.