Titanium is the literally the hardest metal I've worked with. It's still metal though and metal can be polished. It doesn't have to take long either. This piece is a Fish Bone Knotless Gear Tie
. It's grade 2 titanium and measures about 2" X 1/2". I spent about 45 seconds per step with exception of the buffing wheels. Those were about 3 minutes each.
Step 1: Start With 220 Grit Sand Paper
Take a sheet of 220 sand paper and lay it, rough side up, on a flat surface. I'm using a glass block. Apply some metal polish to the sand paper. Meguiars makes different grades which makes things go quicker. For this step I'm using heavy-cut metal polish. Leave some extra polish on the paper so you can "scoop" more up as you go along. Rub the piece in a circular motion. Eventually you'll feel a difference in how the metal feels against the paper. This is because the metal surface is becoming a uniform texture against this grit. Pay attention to where you're putting pressure. The head and tail went faster because of how I was holding it. In either case I only spent about 45 seconds on this grit (and every other grit).
Step 2: Move on to 800 Grit.
Next is 800 grit with medium-cut metal polish. Same rules apply from the last step. If you have stubborn spots you can fold the paper over a file to focus on those areas. See the pictures. Inspect the metal surface and make sure the entire area is the same texture. You want all scratches from the 220 gone. You may have to wash it off to get a good view.
Step 3: Move on to 2000 Grit.
Next is 2000 grit with metal finishing polish. Same rules apply from the other steps. For stubborn spots fold the paper over a file. Inspect the surface and make sure the entire area is the same texture. Make sure all scratches from the the 800 are gone. You may have to wash it off to be sure.
Step 4: Move on to a Buffing Wheel.
Load a buffing wheel with polishing compound and buff the piece against it. Keep in mind titanium gets hot very fast. You may want to keep a bowl of ice cubes near by.
Step 5: The Final Finish.
Up until this point the surface will have swirl marks in it. Use a paint polishing compound to clear it up. Again, Meguiars has good stuff. Make sure you use a different wheel than the one you used in the last step. It not you'll just keep putting in more swirl marks.
Thanks for reading.