Green Turning Blank Storage and Handling
Some of the most frequently asked questions we get from turners who are unfamiliar with green wood turning include: How should I store the wood? How long will it take the wood to dry? and Is there anything I can do to speed up the drying process? This month we will answer these questions in full detail for all who are unfamiliar with turning green wood.
Q: How should I prepare green turning stock for storage?
A: Any green turning blanks purchased from us will come fully sealed in paraffin wax, which slows the rate of drying and vastly reduces the chances of checks or cracks occurring while drying. If you plan on cutting your own turning stock, you'll want to make sure you do a few things. First and foremost, the pith (center) of the tree should be removed from your blank. Leaving the pith in a piece of turning stock will eventually cause the blank to split out from the center and reduce the amount of useable wood you will have. Secondly, you'll want to make sure you seal the outside of your wood. Paraffin wax is by far the most effective tool for sealing, but products such as end grain wood sealers (such as Bailey's or Anchorseal) and latex paints will work effectively in most situations. Coat all outer surfaces of you turning stock, paying particular attention to areas with exposed end grain, knots or heavy figure. Areas such as these should receive extra coats of sealant to help reduce the chances of defects occurring during storage.
Q: Where should I store green turning stock?
A: Properly sealed green turning stock can be stored in a variety of locations. The best storage areas will have three things: light to moderate air flow, temperatures of 60-70 degrees, and a moderate amount of humidity. Air flow is important to control the rate of moisture loss. Storing wood near fans, a/c or heating ducts is not recommended. Although increasing the air flow will speed up the drying, you also increase the chances of causing defects to occur. Temperature is important for two reasons - to control the rate of moisture loss and to inhibit the growth of molds, mildews and fungi within the wood. Temperatures between 60 and 70 degrees are optimal for drying and reducing the growth of unwanted organisms. Lower temperatures will reduce the growth of unwanted organisms, but reduce the drying rate. Higher temperatures will increase the drying rate, but also increase the growth of unwanted organisms. Humidity levels affect wood much like temperature. High humidity levels (above 70%) will reduce the drying rate of wood, and at the same time increase the likelihood that mold, mildew and fungi will be able to grow. Low humidity levels (below 20%) will dry wood too quickly, but will also greatly reduce the problems caused by unwanted organisms. For this reason, humidity levels should be kept between about 30% and 60% at most times to provide slow, even drying, and keep the wood free from other pests. If you can find a suitable area that fits these criteria, then find a shelf, stack your wood with some space between the turning blanks, and let them sit until you're ready!
Q: How long will the wood take to dry?
A: This is a very tough question to answer. The speed at which wood dries is dependent upon the amount of moisture initially in the wood, the density of the wood, the environment in which the wood is stored, and several other less important factors. Just picking up a piece of turning stock off the shelf and judging its weight will not tell you the moisture content, nor will using an inexpensive moisture meter that reads the moisture content near the wood's surface. Generally, we recommend that wood is given at least 1 year per inch of thickness to air dry to between 10%-20% moisture content. After this point, the wood can be stored indoors in a dry, well ventilated, climate controlled area for a few weeks (such as inside your house), which will remove the remaining moisture and dry the wood to its final moisture content, much like kiln drying wood. If anyone ever has specific questions about their given situations, they are always welcome to email us at firstname.lastname@example.org to get more detailed instructions and advice.
Q: How can I speed up the drying process?
A: There are a variety of ways to speed up the drying process in whole pieces of turning stock, but we highly recommend that they only be attempted after experience has been gained. There's no point in speeding up the drying process if it's going to cause your wood to degrade quickly. If you do wish to speed things up, however, here is what we recommend trying. First and foremost, the coating placed on the outside of the turning stock can be removed from areas that do not have exposed end grain (for example, along the length of spindles, or the top and bottom surfaces of side-grained bowl blanks). This will allow the wood to expel moisture more quickly. Other ideas include increasing the ambient temperature around the wood, decreasing the humidity levels around the wood, and increasing the airflow around the wood. Any or all of these techniques will speed up the drying process...just take care to not overdo it and waste a good piece of turning stock!