This project was another go at the green turning of Sycamore and regular readers may recall that my first pass at this process was not a resounding success because the method I used, storing the rough turned blank in a paper bag of shavings to dry and distort through water loss to final size, predictably resulted in a major crack, or check.
This time I used a different method which involved coating the rough turned piece with Anchor Seal, a wax emulsion usually used in lumber yards and at timber mills to coat the end grain sections of dimensional lumber to prevent checking, but which works equally well, albeit in much smaller quantities, for controlling moisture loss from rough turned bowl blanks. I discussed this process at some length in the post immediately preceding this one so I won’t repeat it here. If you have trouble locating it, simply search the site for a reference to Bradford Pear (I can’t link to it because it isn’t published just yet).
This piece was rough turned back in January 2015, coated in Anchor Seal and allowed to simply sit, gathering dust and debris in the shop. No special storage conditions are required but I would be cautious if I lived in an extremely hot and/or dry climate. It helps that my shop is located in a basement where temperatures remain fairly constant throughout the year. During the intervening time, I repeatedly weighed the rough turned blank and recorded the weights, including the weight when first green turned. The blank lost weight over time, as intended, as this represents the slow release of water from the wood. The Anchor Seal helps ensure that the water loss is slow enough to prevent checking but not so slow as to prevent the loss of the water over time. Some sealants promise to achieve the same effect in up to half the time, but I am still testing those assertions and I wasn’t impressed with the difficulty of application or clean up thus far.
Eventually the blank stopped loosing weight and once I had recorded a consistent weight over about three months of time I felt it was same to assume that the blank was dry and ready to finish turn. I had created an internal divot on the bottom of the blank, as I usually do with all bowls I turn, and I was pleased to discover that my Nova Chuck would still fit and could achieve a good grip despite some noticeable degree of deformation and warping during the drying process, a factor which was completely expected, although different woods will deform and warp to varying degrees ranging from minimal to absolutely wild, such as is the case with Red Gum (Liquidambar styraciflua).
I was easily able to bring the rough turned piece back into round, carefully working on both the exterior and the interior with the piece mounted quite securely on the Nova Chuck. Once I finished the final cuts with the turning tools, I sanded to a fine finish of 800 grit. I then applied my favorite finish, ShellaWax in the liquid format and buffed to a nice shine. It was then an easy matter of reverse mounting in a set of Cole Jaws to make the final finishing cuts to the back, sand the final spots, and finish.
I was very pleased with the results of this small green turning experiment that had an outcome far superior to my original attempt with Sycamore. I grow more and more comfortable with the green turning process and expect that I will use it more routinely in my turnings to come.