Article: Al Stirt Demonstration For CMW October 19, 2013
October 26, 2013 17:42, submitted by Tina Collison (author: Bob Gunther, photos by Scot Roberge)
CMW Demonstration by Al Stirt on October 19, 2013
Al Stirt lives in Enosburg Falls, Vermont. He has been a professional woodturner for nearly 40 years. He specializes in open bowls and platters – both utilitarian and decorative. Many of his pieces incorporate carving and painting. He tries to emphasize the ideas and feelings behind his work in addition to the technical details. His work is included in numerous public and private collections including the Smithsonian Institute, the White House, the Victoria and Albert Museum and the American Craft Museum. Al has demonstrated woodturning in Australia, England, Ireland, New Zealand and Canada as well as throughout the United States. In 1997 the American Association of Woodturners awarded him an Honorary Lifetime Membership for his commitment and contributions to the field of woodturning. He last demonstrated for CMW on April 19, 2003.
Al began his demo with a slide show showing his home in Enosburg Falls Vermont. Individual pieces of his work were shown that showed interesting grain patterns and the use of different texture techniques. Several fluted vessels were shown as well as pieces that had geometric designs carved into their surfaces. Much of his carving is done through a coat of black acrylic gesso. This produces crisp lines to the patterns. He also uses milk paint on textured surfaces and then sands the surface to reveal the wood on the most raised surfaces. Al also showed and discussed the positioning of a vessel between centers so that the grain patterns would be centered or altered to give pleasing patterns on the vessels interior surfaces.
He began his turning with a 12 inch diameter, 8 inch thick piece of sycamore. When obtaining a blank by cutting a log in half Al tries to make the cut parallel to the bark. To mount the blank on the lathe he uses a homemade bowl driver. The center of the driver has a screw with the threads removed. It also has two pins in place on either side of the center pin. It is shown on his website - www.alstirt.com. A hole was drilled in the center of the cut surface of the blank. The piece was then mounted on the pin in the driver which was attached to the jaws of the chuck. The tailstock trapped the piece between centers. The bark had been removed from the center of the piece where the tailstock attaches. The piece was balanced using the tool rest as a guide. The two off-center pins on the driver were placed into the piece cross grain. A face shield was used as is Al’s rule whenever turning.
Al began turning with a 5/8 inch bowl gouge (diameter). He uses a modified Irish grind. It has swept back wings. The grind angle is about 65 degrees. The piece was shaped beginning at the tailstock end. He then balanced the piece by removing wood from the headstock side. There was a small crack that was removed in the process of balancing. The remainder of the bark was removed and the piece was further shaped. At this stage further balancing was done using the growth rings as a guide. The piece was slightly shifted on the tailstock to achieve balance. The balance was checked and the piece again shifted to an even more balanced position. A foot was turned on the tailstock end to fit the jaws. Al used a detail gouge to form the foot.
The piece was placed in the #3 jaws. Al does not form a shoulder for the chuck. He then hogged away the excess wood on the tailstock side and began hollowing. After hollowing to a depth of 2-3 inches the tailstock was removed. The jaws were tightened because with wet wood the piece can loosen. He then completed the rough hollowing. He then would wax the bowl with 50-50 water/anchor seal. He waxes all the end grain and the entire rim. He stacks the rough turned pieces in an unheated area of his shop and uses a moisture meter. When the moisture content is down to 20 percent the pieces are moved to a heated area.
Al then switched to a pre-turned dry cherry bowl. The nub on the base had been removed so he had to find the center. It was located and the piece was placed between the tailstock and a flat jam chuck. The back and the foot of the piece were turned true. A small 3/8th inch bowl gouge was used to make the final cut on the foot and the outside of the bowl. A shear scraper was used with the burr removed to give an even, smooth surface. (The shear scraper had the rough bur left by the grinder removed. A fine bur was put on with a diamond hone.) He then turned beads on the back of the bowl using a (modified) spindle detail gouge. A Scotch-Brite pad was used to clean up any fuzz on the surface. The piece was then reversed in the jaws. The rim was turned and then the unevenness of the interior removed starting at the outer diameter and working inward. A better finish was done using a gouge with a secondary bevel. This was completed to the bottom. It would later be sanded. This completed the morning session.
Al began the session using the vacuum chuck. He placed the piece turned in the morning session on the vacuum chuck so that the base or bottom of the piece could be turned and finished. The tailstock was brought up to center the piece on the chuck. The tailstock is left in place as long as possible. A detail gouge was used to clean up the foot and a finishing gouge to do the base. The base was undercut to give a concave shape with a rim left around the edge. Beads were formed on the bottom. It would later be sanded.
Next Al placed an 8x8x2” piece of cherry on the screw chuck with a spacer so that the screw hole did not go the full depth of the screw into the wood. He first turned the tailstock side. He stressed the inherent dangers of turning a square piece with the four pointed corners flying around at 2000 rpm. When turning a square piece one needs to take light cuts to prevent splintering. He removed wood from the outer edge while observing the top profile. One needs to leave extra thickness on the edges so that there is some wiggle room when turning the top surface. A sheer scrape was used to clean up the edge. Al then used a smaller shear scraper with a burr to make a series of coves as a form of texture. It would then be Scotch-Brited and painted.
Al then turned the above cove texturing away and again shear scraped the surface. He then laid out a series of coves using pencil marks. He turned shallow coves between the lines (total of 3 on the back of the square edge piece). He wet the wood with a water spray to lubricate the wood to give a smoother cut when he turned a series of closely spaced lines as a texture. This was then Scotch-Brited.
The piece was reversed and placed in the jaws. The top was trued up. Then the top was shaped into a shallow ogee shaped bowl. Al began to do the final cuts beginning at the edge and working inward. Again the area was wetted and shear scraped. He did this process in increments working his way toward the center. He removed the tailstock and finished the center area with the shear scraper. The center area was then hollowed into a shallow bowl. Al textured the bowl with a finishing gouge producing a series of lines. Scotch-Brite was used to clean up the texture.
Al then turned a shallow groove just to the outside of the hollowed area. This formed a barrier between the bowl portion of the piece and the outer areas to be textured. A pattern was then laid out on the outer surface using concentric circles and radial lines. The radial lines need to be dead-on center. The concentric circles were about ¼ inch apart and the lines were every ¼ wide around the bowl circumference. Once the pattern was laid out the piece was removed from the jaws and placed on the vacuum chuck with the tailstock brought up to the base. The foot was refined. The tailstock was removed and the foot completed with a series of coves. The surface was then Scotch-Brited.
The piece was removed from the vacuum chuck and placed on a vacuum carver’s vise that can be tilted to any angle one wants. This facilitated the carving process. Then a micro motor tool was used (Micro-Pro) with a rotary chisel to create a design on the previously drawn pattern (concentric and radial lines). Al first used the three line bit and cut the concentric lines. He did not keep exactly to the lines nor did he make continuous lines. He then did the radial lines and again made irregular cuts – not exactly on the lines and not continuous. Then the gouge chisel was used on the second quadrant of the pattern. A similar series of cuts were made as on the first quadrant but these were cut much smoother than with the three line chisel. The third was done with a third type of cutter. The fourth was done with a mini-monster burr from Woodcarver Supply in Florida. Here the radial lines were cut continuously. Then the spaces between the lines were filled with further lines in an irregular layout but basically parallel to the radial lines. These lines were less continuous. Finally an area was textured using a carbide ball cutter that cut a series of S-curved waves.
The entire above textured areas were cleaned up to remove any fuzz. Scotch-Brite can be used. A nylon bristle brush can also be used on an electric drill. A third way to clean up is with 3-M radial bristle brushes at a slow speed. If one uses them too aggressively they will fall apart.
Al used black milk paint to paint the entire textured areas. A hair dryer was used to hasten drying. Small areas lacking paint were touched up using micro brushes from Lee Valley. Scotch-Brite was used to rub off some of the paint from the more protruding parts of the texture and reveal some of the wood underneath. This process also polished the wood. An oil finish can be applied or a spray lacquer to protect the surface.
This completed a very interesting and informative demo. Much more information can be obtained from Al Stirts' website
Submitted by Bob Gunther, photos by Scot Roberge.