It started with a message broadcast to all Honolulu Woodturner members. A large Cook Island Pine had been cut down on a property being cleared for a new dwelling off Pali Hwy north of Honolulu. Two large pieces had been set aside and the owner wanted items turned from the salvaged log sections. I met with the owner and saw two pieces that measured larger than the 24″ capacity of my lathe. My charge was to “make whatever I wanted” so she would have pieces from this tree. First I had to cut the two sections in half to have any chance at getting the wood to my shop. With my nephew’s help, we both barely managed to lift the four pieces on to my pickup. Once home and in my driveway, the pieces are literally dropped off the tailgate.
It was about a month later that I was able to get to this project. The clock started ticking on the splalting process as soon as the tree was cut, because at least one “golden” piece was desired and evidence of splalting appears in about a week. First I scribed a circle after the bark was removed. A series of angled cuts with a chain saw got the piece under 24″ and I was able to fasten a faceplate to it and mount it on to the headstock.
Turning begins. With this mass of wood spinning, you have to start out fairly slow. As the eccentricities are removed, the speed can be increased without vibration. Getting to a round shape was actually relatively easy in this case, because common practice is to start roughing out with the bark still on and the log is often out-of round. The bark is about 5/8″ to 3/4″ in thickness.
Here the piece has been turned round and the desired shape achieved. A tenon is left to reverse the piece on the headstock to begin the hollowing process.
Here the piece is reversed and the tenon is held in a 4-jaw chuck. Notice there is a stain in the center of the log and some spalting has begun.
Hollowing in progress. This is turning into the end grain of the wood. Whenever possible, I try to use the gouge in a downhill cutting mode rather than in an uphill mode against the grain of the wood. On the outside of the piece, this results in cutting from the rim towards the center of the piece. On the inside of the bowl, it is the opposite–cutting from the center of the piece towards the rim. For hollowing the inside, the strategy is to hollow a narrow shaft down the center of the piece so cutting can then proceed from the middle towards the outside. As the center hole is widened, the cuts are downhill and long continuous shavings can result, some over 6′ long.
In this photo below, hollowing has progressed to where the rank of branches are encountered. Norfolk Island and Cook Pine is noted for its branches being on the same level rather than occurring haphazardly on the trunk. The branches go from the circumference to the middle of the log. A pattern of knots can then be seen wherever the branches are being cut on the piece. While the star pattern seen here is very attractive, the goal on this piece was the overall outside shape, and the inside shape should ideally follow the outside shape. To match the outside shape, the inside cutting has to proceed beyond this star pattern. The branches will result in dark ovals on the side of the piece. There can be as little as 4 or as many as 9 branches off the trunk at any position. If the goal on the piece was to achieve the star pattern, I would have to stop here and somehow make the outside shape match the inside shape. Another quarter-inch of cutting could affect the star patter drastically, so you need to know when to stop hollowing. This takes a little practice and trial and error.
When the still-wet wood in thin enough, it will show translucence. A strong light from behind will help gauge the thickness as a thinner area will transmit more light. This translucence will be lost when the wood dries.
Ron Kent was one of the pioneers of soaking thin Norfolk and Cook Pine multiple times in an oil-based solution. After the wood dries, the piece is sanded smooth and immersed in a soaking solution. This solution can be right out of the can Watch Danish Oil Finish (natural), or a proprietary mix of your choosing. There are many recipes out there. My recipe is a slight modification of what late Russ Fairfield called his “Witches Brew”. One gallon boiled linseed oil, two gallons paint thinner, and one quart spar varnish. Instead of varnish, I use one quart of oil-based polyurethane. The substitution is primarily because of the difficulty of finding an oil-based varnish as most products have become water-soluble. Ron Kent shared his belief that the translucence is achieved when the oil solution replaces the water in the cells of the wood; a polymerization occurs and is not evaporated from the wood as when the piece is first turned and dries. He also believes that there has to be a repeated wet and drying process to occur to get the polymerization complete. Wet-sanding after the soak also helps the liquid penetrate the wood. The soaking and drying process is repeated until translucence reaches a point of diminishing return. One cycle is soaking overnight and drying the next day. On this piece, the wall thickness is 1/8″ to 3/16″. Soaking of the piece was discontinued after 9 cycles. Wet sanding was done by hand after each soak, starting at 220 grit and increasing in smoothness until 1200 grit.
After the Beall 3-buff system, this is the result. This shot was taken outdoors in partial sunlight.
This shot taken in the same location; at dusk with a floodlight from above. Final diameter of this piece is 21-1/4″. Height is 6-3/4″. To go from start to finish on a piece this size without any glitches is quite an accomplishment for me.
GREAT ARTICLE & nice piece!! thanks for sharing tg
David, very nice work and beatiful at that. Thanks for sharing the story.
Aloha, David…I cut a few pieces of NIP when I was in Hawaii spring of 2013…the wood was sealed with a type of ? marine wax? and has been in the dry in a wood shop in north carolina ever since….how much spalting should I expect…is moisture the prime contributor to spalting…I like some light spalting not heavy….thanks again for the article and great job on the turning…tim green
Sorry for the delay in this response. Repeated soaking and drying are contributors to spalting, but if kept under cover cover, NIP will spelt any way, albeit very slowly. If you like light spalting, and the piece is left in the weather, you should turn it within 6-8 months. If you had it sealed and under cover for a year, then the spalting should be somewhat light. This is an educated guess, but hard to predict with certainty.
Do you work with Koa?
Yes, I work with koa. It can be a spectacular wood, but it is not an easy wood to finish, and can be very expensive.