Phil Taylor: Turning from Talc or Soapstone

Phil practiced dentistry for 29 years. He retired 22 years ago. He restored classic cars for several years after retirement and took up wood turning about 14 years ago, about the same time Kirk DeHeer started turning. He first saw a stone turning demonstrated by Lee Carter at the Utah Symposium several years ago.

About Talc (or soapstone)

Talc is a very soft stone (Blackwell hardness of 1). It occurs in many places in the world but the nearest quarrie to us is in Montana. Talc is used industrially in many applications but largely in cosmetics and skin powders. These users prefer white talc so colored talc is often regarded as unacceptable; however, it is excellent for turning. Talc can be cut with high-speed steel turning tools and standard bandsaw blades. It is very easily scratched so in finishing stages it might best be handled with cotton or vinyl gloves.

If talc is turned at low speeds (< 500 RPM) it is less likely to create dust. The dust is also heavy enough that it settles quickly rather than clouding the air. Alabaster is more prone to dusting. A dust mask is still a good idea for safety. Talc pieces often contain fissures that can result in disintegration at higher speeds unless stabilized by filling the fissures with thin C/A glue. Thus a face mask is also a wise precaution. Because of its softness and absence of fibers talc is less demanding of tool sharpness than wood; however, sanding is critical to achieve a good finish. More of the turner’s time will be spent in sanding and polishing than in tooling the stone.

Preparing the Stone

Talc generally comes in chunks. Phil inspects the raw chunk to determine how best to saw the stone to minimize waste. He uses a bandsaw to make an initial cut to provide a flat base from which other cuts can be made. He can then cut the large chunk into smaller blocks. Most of his stone turnings are quite small. In this demo he began with a blank about 2½" square by 2½" long. He also uses the bandsaw to cut the blank into a rough cylinder. It is important that the base of the blank be flat and smooth. He glues a waste-block disk (¾" flat stock) on the face of a 3" face plate with C/A glue. He then glues the flat base of the stone blank onto the waste block with C/A glue taking some care to center the stone blank as well as he can. When the glue is well set the assembly is ready to mount on the lathe.

Turning the Exterior

Phil uses the Henry Taylor mini tools for shaping cuts. His favorite tool is the ¼" gouge but he also made use of the parting tool and the skew. The design he chose to demonstrate was a miniature pedestal bowl. The 2¼" diameter bowl sat on a cove-cut pedestal with a stem diameter of ¾" and a flared base diameter of 1" to 1¼". The waist of the bowl was at the 2/3 point of the total height of the piece. The lip of the bowl was beaded and a narrow flat fillet separated the bottom of the bowl from the upper flare of the cove-cut stem. He mounted the face plate and stone on the lathe and ran the lathe at about 400 RPM with the outboard face of the stone blank supported by a live center in the tailstock. He used the ¼" gouge to turn the blank to a cylinder and then began rough forming the base and stem of the piece. The base was oriented at the tailstock side of the blank. He reduced the diameter of the base to about 1¼" and gradually defined the cove of the stem and the round curve of the bowl. He used a skew to cut the fillet at the bottom of the bowl. After moving the tail stock out of the way, he turned the bottom of the base to a slightly concave profile and then cut a flat square groove into the base to provide detail and a band in which to scribe his name later. This 3/16" wide groove was cut with a square end scraper (or parting tool).

With the profile of the piece established he began finishing the exterior with 240 grit sandpaper progressing through 600 grit. As he identified fissures or defects he filled them with C/A glue and retreated to 240 grit paper as needed to eliminate the flaws. Final sanding was done with 1200 grit wet/dry abrasive paper with liberal use of water to lubricate and clean the surface. Phil began the polishing process with EEE Ultrashine abrasive wax which he applied fairly liberally with a cloth with the lathe stopped. He then buffed the entire surface with the rag while the lathe turned. Phil pointed out that as you buff the EEE its abrasive particles break down to provide finer and finer grit. After the buffing he wiped the surface with a clean cloth and then applied friction polish with the lathe turning. This sequence produced a smooth and glossy surface.

With the exterior turned and polished, he removed the stone piece from the waste block. He used a thin parting tool to cut through the wood of the waste block without marring the glued face of the stone.

Turning the Interior

To hollow the interior of the bowl it is necessary to reverse-chuck the stone piece. He trued up the face of the waste block and then used a caliper to transfer the diameter of the base of the piece onto the dressed surface of the waste block. He used a skew to cut a shallow, flat recess into the waste block. The recess must be flat to mate well with the bottom face of the base. The diameter of the recess should not be too tight, but it should not be so large that it makes centering the base in the recess difficult.