A woodworker is building chairs out of air-dried oak and wants to know how to prevent the stains he’s getting from the spacers he’s using
Ian Kirby: The common practice to prevent staining is to have the stack under cover ? don’t let rain get on it ? and use stickers of the same species
Ellis Walentine: Sticker stain is a big problem with air-dried lumber, but the good news is that there are ways to reduce it. Sam Talarico of Talarico Hardwoods in Mohnton, PA, says he has virtually eliminated the staining problem in his lumber with a few simple rules of thumb: First, if possible, fell the trees in the winter, when the sap is down. Second, use fluted sticks, preferably red oak or another hard wood. Apitong and ipe work well, but the wood is pricier. If you’re drying lots of wood, you can buy specially fluted sticks by the thousands from commercial mills that make them especially for this purpose. You can make your own by kerfing squared stock on the table saw, either lengthwise or at an angle across the faces, on all four sides.
Depending on your wood’s tendency to stain, you might need to move the stickers as often as once or twice a week, shifting them slightly and rotating them 90 degrees each time. Allow plenty of air circulation at the beginning of the drying cycle; just a roof over the stack will do. After a couple of weeks, wrap the stack in Shade-Dri or other permeable polypropylene screening material that will keep the rain off without blocking air movement through the stack.
It may take you a few cycles of experimentation to figure out how many of these measures are necessary to prevent staining on various types and thicknesses of wood.