38 - Ring Boxes, страница 27
first layer. With the basic ^groundwork complete, Ted was ready to set the first layer of boards in place. Once again, leaving at least an inch of space between boards allowed the air to circulate.
building the stack. At this point, the lumber stack started to take shape quickly — another row of stickers followed by a layer of boards, see Step 4.
As Ted built up the stack, he kept the stickers in straight vertical rows — directly over the 4x4 posts. This way, the weight of the lumber transferred down through the stack to the posts.
more plywood. At the top of the stack, he added one more piece of plywood, see Step 5. This panel keeps any moisture that gets into the porch off the top layer of boards.
But more important, it slowed down the drying time of these boards by covering their exposed ^surfaces. Without the plywood, the air moving across the boards would remove moisture too rapidly and cause them to check.
concrete blocks. The boards at the top of a stack are also more likely to warp. The reason is simple. Unlike the boards buried in the stack, there's no weight pressing down on them from lumber above. So to keep
6 The stack is weighted down with concrete blocks to prevent the top boards from warping.
7 To minimize checking caused by losing moisture too rapidly, paint the ends of the boards.
the top boards flat, Ted set heavy concrete blocks on top of the plywood, see Step 6.
paint ends. Finally, Ted coated the end of each board with latex paint, see Step 7. The paint served an important purpose. It minimized checking by preventing moisture from blowing out the ends of the boards too rapidly. Instead, the moisture escapes much more slowly from the edges and faces of the boards.
After building the stack, Ted only had one thing left to do — allow the lumber time to dry.
Just how much time? The old rule of thumb is about a year per inch of lumber thickness. So to dry his 2"-thick boards, he figured it would take about two years.
But that's really just a guess.
moisture meter. The only way to know for sure is to check the lumber from time to time with a moisture meter. (For more information on moisture meters, refer to ShopNotes No. 30.)
A meter will give the exact moisture content of the lumber. Ideally, the boards should be around 6% to 8%.
But as long as the lumber was exposed to the humidity of the outside air, it would never reach that ideal moisture content. The best Ted could hope for would be around 15% to 20%.
stack indoors. So when the lumber eventually does reach that point, Ted will still have one more thing to do — move it indoors to a heated location where the final drying can be completed.
BOARDS IN EACH LAYER ARE SAME THICKNESS
PLACE HIGHEST-QUALITY BOARDS IN CENTER OF STACK
PAINT ENDS OF BOARDS TO PREVENT CHECKING
4x4 PRESSURE TREATED POST
1" x 2" STICKERS PLACED 1&" APART
PLYWOOD STOPS MOISTURE FROM DAMAGING LUMBER
Adding a final piece of ply-_ wood keeps the top layer of lumber from drying too quickly