About 6 weeks or so ago, I decided to continue my exploration of the “green-wood” turning process. Up to now, all the wood I have turned into bowls on the lathe, mostly using exclusively turning tools from the Easy Wood Tool company, has been dried either in commercial kilns, or more commonly, very slowly over years of waiting as the wood is stored in my basement at relatively consistent temperature, no direct light, and the typically higher humidity common to the southern United States. The advantage of dry-wood turning is that the piece is very unlikely to warp or check (a fancy wood-turning word for cracking) and the bowl blank can be transformed into a finished bowl in one day quite easily. The disadvantages include the fact that most commercially sold wood is sold green, usually waxed to slow drying, so the dry-wood turner has to wait potentially years before experimenting with an interesting new species; dry wood is more difficult to turn mechanically than green wood (green wood cuts very quickly although it does make a mess with water spraying out depending on how wet the wood is); and if the green-wood isn’t dried properly and slowly the blank can check before it is even turned, leaving you with expensive firewood, depending on your tolerance for “unique” pieces.
Up to now I have always been more afraid of the hazards of green-wood turning that attracted by the benefits. But as I have gained practice and competence in dry-wood turning, I have decided to slowly start to experiment with the green-turning process. I made four small dishes from green Cucumber Magnolia and that turned out pretty well as the wood did not warp dramatically during drying and it didn’t check at all. Next, I then decided to use a larger piece of American Lacewood, which is in fact Sycamore that has been quarter-sawn to highlight the vivid ray patterns.
The blank was sold to me fairly well rounded so I didn’t have to cut it on the bandsaw. I simply mounted it on the face-plate to cut the divot on what would be the back of the finished piece to mount the blank on the lathe with the Nova chuck. Then I reversed the piece on the Nova chuck and cut it roughly to the shape I thought I wanted being sure to leave pretty thick walls all around so as to have sufficient material left to remove during final shaping once the piece dried completely. I have read that one should always leave at least 10% of the original dimension of the blank, so a 10″ blank should always have at least 1″ walls left during green-turning.
I placed the rough turned piece in a paper grocery bag filled with wood shavings, closed the bag and set it aside to dry. This method has worked well with the Cucumber Magnolia previously. After about a week I opened the bag to check the piece and discovered something quite interesting. One side of the piece, the side with the most pronounced ray fleck pattern, was still quite wet, over 40% moisture on the surface according to my moisture meter. But the other half of the same piece of wood was much drier, about exactly twice as dry with the moisture meter indicating about 20% moisture. Both sides were still too wet to finish but I had never heard of wood drying in this way and in fact I still haven’t found anyone else who talks about this drying effect.
Rough Green-Turned Sycamore Bowl
I put the piece back in the bag and let it sit about another week. This time when I pulled the piece out, I was disappointed to discover that it had checked, completely through, on one side. There was another much smaller check that was beginning to form near the one that had fully occurred. There was nothing to do about it now, so I had to decide whether to toss the piece as ruined or to try to work with the check somehow. I sometimes think that checking adds a unique bit of character to a bowl so I decided to keep it and see what I could do with it. My initial thought was to experiment with Inlace, a commercial in-lay product that is available in a variety of colors and which can also be enhanced with metal powders and other “special effects.” I had bought an Inlace kit years ago and figured I had nothing to loose with this piece since it was already checked.
At that point I went ahead and turned the piece down to approximately final dimensions but then I set it aside just in case it wasn’t completely dry yet. I left home for about 10 days and when I returned it was obvious to me that the bowl had continued to dry, and warp, while I was away. The question to answer was was there adequate material left to remount the bowl and turn it down to round once again, or had I cut it too close previously?
Finished Green-Turned Sycamore Interior
Let’s just say that it was really close. As it is, the piece is not actually perfectly round, being out of round by about 1/16″, which isn’t terrible but certainly not perfect either.
I opened the can of Inlace, which is a two-component product, consisting of the liquid portion which is colored and a hardener chemical that is used in drop quantities. There was no expiration date on the Inlace but there should be because by the time I opened it, it was completely separated into a gummy clear layer and the mostly dry colored portion. I tried to mix it but it was clearly beyond hope and I was forced to toss it out. That wasn’t a good feeling because kit of any one color of Inlace sells for about $25.
So, I was left with the check and decided to make my own version of Inlace. I carefully gathered up the finest of the shaving dust I could find from working on the bowl to bring it, mostly, back into round. I then added a generous dollop, no specific measurements required for this method, of thick cyanoacrylate and stirred it thoroughly. I then used a wood applicator to gob the sawdust and glue mix into the check, letting it mound up a bit to ensure it was completely full. I sprayed it with accelerator and then cut it back down to smooth on the lathe. Now, I won’t pretend that you can’t tell that something happened at that spot, but that would be true with Inlace as well, and even more so as the Inlace I had was a light blue color with sparkly material in it. At least this way the in-lay material is wood colored because it is wood, and even the same exact species as the bowl on top of that. It doesn’t mask the situation but it looks better than a plain check. Or at least I think so.
Finished Green-Turned Sycamore Exterior
Finally, I sanded it all down as usual and finished with Shellawax liquid.
I won’t pretend that it is the nicest piece I have produced, and in fact, I would rather say that it is one of the pieces I am least proud of in the past few years of turning, for multiple reasons associated with not just the check and the out of round nature of the piece, but also because of problems with the finish sanding and the finish itself that are both side-effects of it being out of round. But it isn’t a complete failure because I learned from the experience.
In the future, I won’t rely on just the paper bag with shavings for drying green turned bowls. Instead I will further experiment with products such as AnchorSeal and Pentacryl, both of which are designed to slow the drying process of green wood to help prevent checking and excessive warping associated with uncontrolled drying. I also learned that woods can dry in unpredictable and uneven ways. And I learned to be very careful about not cutting a green-turned piece too thin until I am SURE that it is completely dry. Along those lines, I learned anew the value of patience in allowing the wood to dry completely instead of making an assumption about dryness based solely on touch and appearance. So, while the finished piece is not perhaps a piece of fine art, it does represent a stop along the learning curve and anything we learn from inherently has value.