Sculpture Finishing Techniques

After you have chiseled your piece so the form is complete, you will be ready to start the finishing stage of your sculpture.

Filing
The final shaping of the softer stones can be done with rasps. Power tools for finishing can sometimes be hard to control and give a mechanical look (bumps/flat planes). The use of rasps provides a more natural, flowing finish. The rasp's scratch marks can be left as a textural element, or removed with sandpaper.
General modeling is best completed with a coarse half-round cabinet file. This will enable you to get the sculpture rid of bumps and flat edges. These would really show up later when you have it sitting under a light source. Riffler files are very useful to smooth out smaller areas and edges. A half-round 10" vixen file is a treat to use it will make your piece so smooth that you can skip the first sanding grade.

Small 6" diamond files are great to get into little spaces and smooth all edges. You can skip the first sanding in the areas you use these rasps. (Wood Carvers Supply ) (5pc diamond file set 60 grit) 
800- 284-6229 http://www.woodcarverssupply.com/store/

Sanding

After filing is complete, use red garnet sandpaper starting with 60 grit, This first sanding takes the longest time. It may take from at several hours to one day. All scratches and white bruises must be gotten out before going to the next grade. I usually count to 15 before moving on to the next area of sanding on a piece. At this stage you can use fine diamond files to "clean up" the lines and edges of planes. The file is basically 60 grit
The next grit is 150 grit. These first two sandings can be done by hand or power tools depending on the form. Figurative forms are much more difficult to sand by machine.

Abstract forms with flat shapes are easier to use power sanders. An electric drill and cushioned sanding pad with adhesive sandpaper can be an economical way to power sand.
For the last grades of sanding, use water with your wet/dry carborundum sandpaper 220 grit, 320 grit, 400 grit, 600 grit and finally 1200 grit. You can either put your stone in a plastic tub with water or simply dip your hand into water occasionally as you sand..
1200 grit sandpaper can be purchased at a auto parts store. All the other sandpaper can be bought at a hardware store Alabaster polishes to 1200. Marble begins to show a polish at about 600 grit. Granite doesn't polish until 3,000 grit. Buy at local hardware store.
Limestone does not require as much sanding because it will only polish so much. 220 grit is the final sanding for limestone.

Wax
For a soft shine, apply mink oil polish ( shoe store).as directions on container. After polishing the stone apply a thin layer of a clear paste wax. (floor wax from hardware store). After 5 minutes polish to a shine with a clean cotton towel or electric buffer.
Montoya sells other materials to polish stone that will give the stone a stronger shine than the wax.