Creative Woodworks & crafts 2005-06, страница 50

continued from page 49

The easiest way to distinguish between red and black is to check the acorns. The cap on the red is flat and saucer shaped, and the cap on the black is bowl-shaped and slightly hairy, with fringe-like scales.

Oak has been prized for all sorts of construction, from ships to line cabinetry, bccmi.se it has been a dominate species throughout its range worldwide, is fairly easy to work, is very strong, and has a beautiful appcarancc. The red oak group, for the most part, is not rot resistant, and it must be treated if used in damp or wet conditions. In all oilier conditions however, it is very

durable, as evidcnccd by construction still standing after several hundred years.

The wood machines with moderate difficulty using hand or power tools and is fairly stable in service, although if has a hirge shrinkage factor while drying. Here, besides color and grain configuration, lays a difference of interest to woodworkers - not significant - but a difference just the same.

The shrinkage factors are 8.6% for northern red oak, 10.8% for scarlet oak, 11.1% for black oak. and 11.3% for southern red oak. The total effect will Ix; that a 12"-vvide, flat sawn board will move just over 1/4" in seasonal movement, between 6% & 12% moisture content (VIC). You can expect 3/8" loss in width from 20% to 12% MC. So, if you arc making wide panels or doors, calculate the factor properly. Don't forget, the factor is based on weight loss, not. dimension.

I have not found a glue or finish that does not work on these spccics. but because of its open grain you will have to use a filler to get a smooth finish. Another problem wilh oak is tannin or tannic acid. It. reacts with iron and steel, so don't leave nails, chiscls, hammers or the like on the unfinished wood overnight, or you will spend countless hours trying to remove the blue stain. Speaking of color, unless you are lucky enough to get a load of lumber from the same tree or at least the same area, your colors will probably not match i f you are looking for a natural finish. Pins, if you rub the surface with steel wool or use steel fasteners and a watcr-basc-d finish, don't be surprised if yon see blue stains develop in front of your eyes.

The sap wood has a creamy color, and the "heart wood color can range from a very pale pinkish-white Lo a beautiful light red. and will age with a deepening amber color in its natural state. The trees arc prone to mineral stains, which need lo he dealt with by coloring with toners and stains.

Oak cannot be discussed without mentioning quarter sawing. You will pay at least 1/3 more for quarter sawn stock because it takes more lime to mill and has a greater waste factor, but anything made hi the Greene & Greene or Slicklcy style are based on it. In addition, it is a little more stable than flat sawa with 1/8" lo 3/16" movement in service.

As mentioned earlier, red oak has been used in all forms of construction, including ships, cabinets, paneling, flooring, furniture, veneer, caskets, pallets, and slack cooperage. It is cooperage thai differentiates practical use of the red oak group from the white oaks. The red oak group is open grained and very porous, whereas white oak, Querent alba, is also open grained, but is not porous because of a substance called tylosc. Due to this characteristic, white oak is used extensively in tight cooperage, especially for wine and whiskey barrels, and will be featured in a future wood pro file, a c

50 • Crestive Woodworks S Crafts JuriB 2005