Article: Al Stirt Demonstrates For CMW, June 17, 2017
June 23, 2017 11:37, submitted by Tina Collison (author: Ross Lynch, photos by Tina Collison)
Al Stirt Demonstrates for CMW, June 17, 2017
We were privileged to have Al Stirt, a founding member of the AAW, come from Vermont and demonstrate for us on June 17, 2017. He opened the morning session with a 10 minute power point presentation covering his 40 years of woodturning design. He has always been intrigued with patterns-first in wood grain, then adding carving and gradually adding color.
This led to a discussion about grain balancing. This is defined as creating symmetry in the bottom and sides of a bowl. It is mostly about grain but also about color. He initially puts the blank on the lathe with the bark perpendicular to the bed of the lathe. He showed us a homemade “bowl drive” which has a center pin, and two sharpened bolts which go into the side grain. This device will fit on the chuck and using a tailstock center with the pin removed allows for fine adjustments to optimize balancing.
At this point Al took a few minutes to discuss safety-face shields, speed, etc. He did add throughout the demonstration pearls on how to avoid injuries major and minor.
With the blank on the lathe, his first cuts were to remove the bark and then to begin rough shaping the bottom. At this point he showed how to use growth rings to fine tune adjustments for final grain balancing. With this done he finished rough turning the shape of the outside of the bowl and finished forming the tenon. He next turned the bowl and chucked the bowl. He brought up the tailstock and trued the top.
He “softy” cut the edge to make it dull to avoid getting cuts. He then started to hollow leaving the tailstock in place. After some hollowing he narrowed the remaining center wood and then removed the tailstock. He used calipers to check his thickness and prefers to leave the bottom slightly thinner than the top. This helps the bowl dry better. He removed the roughed-out bowl from the lathe, paints with watered down anchor seal, and sets aside to dry.
Al exchanged the roughed out blank for one he had previously turned and dried. He places the roughed out bowl on the lathe with the aid of a homemade rectangular jam chuck. On the ends of the jam chuck he has placed a skid proof (like used on stairs) tape so the bowl won’t slip. This is held in place with a live center with the pin back in. At this point, there was discussion on how thick to rough out the bowl-generally the 10 to 1 rule- and drying techniques.
He showed how he reshaped the tenon and accented the bowl foot junction with a diamond point scraper. He then finished the outside and shear scraped with a homemade scraper made from a 1’ x.25” square ended scraper modified to a slight curved, left sloping 60-degree shear scraper. He uses water as a lubricant during this process and then sands from 120 grit to about 320.
The bowl was reversed and chucked to finish the inside. He first finished the rim and then did the inside in stages first with a regular bowl gouge followed by a finishing gouge. This is done top to bottom with frequent thickness measures. Al then turned the bowl over using a vacuum chuck to finish the bottom with the finishing bowl gauge. If this is a utilitarian bowl, he has been finishing with Seal-a-Cell and after 24 hours applying something like Mahoney oil.
The Afternoon Session began with a few minutes discussion on sharpening. He likes the one-way jig for bowl gouges and a platform for scrapers.
Al next demonstrated a square bowl with a wide rim for decorating. For this he started with a square blank and placed it on a screw center with #3 jaws. He discussed proper setting of the screw and how to use thin wood shims to shorten the depth the screw goes into the wood. The technique is essentially the same as with the bowl except out at the corners. Need to be aware of the corners so as not to get chip out. In this case faster is better. He made a lot of step cuts, smoothed it out and then established the curves he desired. At this point on the bottom he used a narrow home modified scraper to create shallow coves. He used this same tool to put grooves in the coves. With the lathe off, he used scotch-brite to soften the grooves.
Al reversed the blank and places on a small chuck. To cut the corners to the proper thickness he would drag the bevel out until just came off the corner then gently cut. He frequently checked until he had the proper thickness. Once the shape was attained he cut in the bowl. It takes special care because the outside and insides are of different shape and it could be easy to cut too deep. Al then put rings inside the bowl with a pointed scraper and an accent groove outside the bowl. This ring accents the bowl and tells you where to quit carving.
At this point, with the lathe running, Al penciled rings on the rim without measuring and about .25” apart. With the lathe off he did the same with radial pencil lines. These lines are used as a rough guide for carving. He then turned the bowl over and used the vacuum system to finish the bottom.
The rest of the demonstration was devoted to surface enhancements. Al uses his vacuum chuck to hold the bowl so both hands were free. He showed different patterns and designs on the four corners of the rimmed bowl. He used a micro carver, but you can use a Dremel or another tool. He did random carving using rotary chisels, rotary gauges, and rotary saber cutters. He also showed how to use a cutting cylinder to make vertical lines. He then used scotch-brite pad or a radial bristle brush to clean up the carving.
Al then finished this bowl with milk paint. He likes black milk paint on cherry wood especially because the lime in the paint reacts with tannins in the cherry that gives it a metallic look. He applies the paint in a little thinner mix than most and puts multiple coats until it is opaque. This is then sanded with paper or scotch-brite. His final finish is oil or lacquer.
Submitted by Ross D. Lynch
The CMW Library has two of Al Stirt's instructional videos available for rental by members:
Open Bowl Turning: Balancing the Grain DVD and Turning and Carving the Square Platter DVD.
Learn more about Al Stirt at: http://www.alstirt.com
Read about Al's previous demonstration at http://www.carolinamountainwoodturners.org/articles/475
View a youtube video of Al Stirt at: https://www.youtube.com/watch?v=mg0wuh_SapE