Small Bubinga Bowl
My most recent project was turning a small bowl, or dish, from a nice 6”x6”x3” block of Bubinga wood that I had purchased at some time in the past. While I have worked with Bubinga as pen blanks in the past, this was the first time I experimented with a bowl blank size of this very beautiful and very popular exotic tropical hardwood.
A Bit About Bubinga
Bubinga comes from tropical equatorial Africa. There are several species within the Guibourtia genus of trees that may be sold as Bubinga. There are also other commercially important species within this same genus that are sold under other names, including Amazakoue. Some sources will refer to Bubinga as “African Rosewood,” and while Bubinga does often have a rosy coloration, it is technically absolutely not true rosewood. Only species within the Dalbergia genus are true rosewoods and these come from Central and South America and South Asia as well as Africa.
Bubinga trees are large, up to 150 feet tall with 3-6 foot diameter trunks. Because of this large size, some table tops are made from slabs of the tree. Bubinga also frequently features figure in the wood, including waterfall, pommele, flame, quilt, and mottle. I personally have a piece of waterfall Bubinga as well as a platter made from waterfall Bubinga that was made by my father, Steve.
Bubinga is relatively hard as measured by the Janka scale, coming in at 2,410 pounds. This puts it in the range of other tropical hardwoods, hard but certainly not the hardest of the woods. Bubinga frequently has silica contamination which will prematurely dull working tools. It turns beautifully, although large amounts of swirling figure can lead to an increased incidence of tear out, so sharp tools and patience, always virtues in wood working, are essential when working with Bubinga, especially when it is highly figured.
Bubinga is priced in the moderate range for imported tropical hardwoods. A blank of the size I worked with retails for about $20 each, although if any figure is present the price will likely be considerably higher.
My Experience with this Piece
I cut the blank to rough round on the bandsaw as always and then mounted it between centers to turn it true round before mounting the face plate. The hardness of the wood made it difficult to get a good grip between centers and in a few instances the drive center just spun as I tried to cut round. I tightened the tail stock, several times, and ultimately switched drive centers. Once round, I mounted the face plate, again encountering difficulty in maintaining exact center, which necessitated turning back to round, all of which results in loss of valuable wood! This frustrates me immensely and I still struggle to find a good solution to this face plate mounting problem!
The Bubinga cut beautifully with the Easy Wood Tools and end grain tear out was essentially non-existent on the exterior surfaces. This made sanding light and easy. Once sanded down to 800 grit and then burnished with shavings, the natural oils in the wood provided a gloss finish without the use of any other finishing solution or material. This is a common effect among high oil tropical hardwoods and I have polished and burnished Cocobolo in the same way without the use of other finish materials.
I started the hollow on the face of the bowl, once mounted in the Super Nova Chuck, with a Colt forstner bit, which is of very high quality. I then used a variety of Easy Wood Tools to achieve the depth and overall shape that I desired. The interior required a bit more sanding, especially of the end grain areas, than the exterior, but I have experienced much worse with other woods in the past. Overall, the sanding effort was mild to moderate on my scale. Again, I sanded to an 800 grit and burnished the interior and was pleased with the gloss and shine.
Final Steps, Finish and Final Thoughts
The final step was, of course, to turn off the bottom where the divot was, sand, and burnish. Once I took the piece off the lathe and wiped away all sanding dust, I was no longer as pleased as I was originally with the finish appearance. I think some of the oil was wiped away by the damp rag I used. So, since I didn’t trust that I could get enough buffing speed and power for a wax finish now that the piece couldn’t be reliably mounted on the lathe again, I decided to use a liquid finish, in this case Behlen Woodturner’s Finish and I was quite pleased with the results. This finish can be applied while a piece is on the lathe, but it doesn’t require it. And, the finish dries quite fast so there are no prolonged wait times between finishing the different sides of the piece.
I was quite pleased with the outcome of working with this small piece of Bubinga and I made sure that I have more of the wood in my shop for future projects since I so enjoyed it. I have several more pieces, including a foot square with the waterfall figure, so I look forward to several more interesting projects using Bubinga in the future.