Mold for John Hammond's amber cane top

You'll need to split the stl into two objects in your slicer.  There are 4 semi-circles on the mold to assure proper alignment.  

I printed this with a 0.4 mm nozzle with variable height to achieve the smoothest curves I could and to prevent any gaps in the walls.  3 or more walls will also help prevent any holes.  Infill only matters for how re-usable you want the mold to be.  I printed this with an FDM printer, but resin would likely get you better results.

This was my first resin cast, so take my advice with a grain of salt.  After printing the mold I melted some beeswax and rubbed it into the mold to smooth it some more and fill any holes I couldn't see.  I also used a spray release prior to casting.

To finish the cast I power sanded it with an orbital sander at 80 grit to remove any surface pits.  then I hand sanded at 100, 220, 320, 400, 600, 800, 1000, 1500, 2000, and 3000 grit, with wet sanding starting at 320.  After the sanding I used Meguiar's PlastX plastic cleaner and polish per the directions.  It's normally used to de-cloud car head lights, so you can find it or a similar product at any auto parts store or store that sells car cleaning products.  Don't worry if it is still cloudy after 3000 grit.  The PlastX really does a trick.