Popular Woodworking 2009-04 № 175, страница 54
-• Flexner on Finishing ■-
BY BOB FLEXNER
Finishing the 5 Types of Woods
Organize all the woods into categories to determine the best finishing strategy.
'oodworkers choose among dozens of wood species for projects. Unless you've actually used many different woods and experienced how they machine, feel, smell and respond to stains and finishes, you probably find making an intelligent choice confusing. There needs to be some way to organize the woods so decisions are easier.
And there is.
To begin with, you can divide all woods into five large categories: pine and related softwoods; coarsegrained hardwoods; medium-grained hardwoods; fine-grained hardwoods; and exotics.
Traditional furniture is rarely made ol pine or exotics, so lor simplicity's sake, let's reduce the categories to three: coarse-, medium- and fine-grained hardwoods. And to begin with, let's deal with just the five most common traditional furniture hardwoods: oak, walnut, mahogany, cherry and maple.
Importance of Grain
Grain is the most important indicator for identifying woods. Grain is the open pores or pitting in wood that give it texture. In finished wood you may have to look closely to see the grain because it may have been filled.
Most old furniture was made with one of these five woods, so identifying woods in antiques is fairly easy. If the grain is coarse, the wood is likely oak. If it is fine - that is, if there's no obvious pitting - the wood is probably cherry or maple. If there is pittingand it's finer and more evenly spaced than in oak, the wood is almost always walnut or mahogany.
A fan of woods. Pictured are a number of woods woodworkers choose among for projects. Clockwise from the top are pine, oak, walnut, cherry, butternut, mahogany, ash, gum, soft maple, poplar, chestnut, teak, rosewood and ebony.
To tell the difference between cherry and maple and between walnut and mahogany, the color of the heart wood is key. On an antique you may need to cut a sliver from an inconspicuous place to see its color. On newly milled wood, you can simply look at the color.
I f the color of fine-grained wood has a reddish tint, the wood is cherry. If near white, it's maple. If the color of a medium-grained wood ischarcoal gray, it's walnut. If reddish, the wood is mahogany.
Keep in mind that oak can have a coarse
grain when plainsawn, or less coarse when quartersawn. Quartersawn oak is usually easy to identify because of its medullary rays.
Of course, wood identification becomes more difficult when more woods are added. Traditionally, chestnut, elm and ash were sometimes used instead of oak. Each is coarse grained but subtly different. You just have to learn to recognize these differences.
Butternut, hickory and pecan were also used, and theirgrain resembles walnut and mahogany. Color can help in identification. Butternut is tan; hickory and pecan are tan with a slight pink cast.
There are lots of fine-grained woods in addition tocherry and maple, including birch, poplar, gum, beech, yew and holly. Gum and beech have a color similar to hickory and pecan. Yew is light brown to reddish. The heartwood of poplar has a distinct greenish color, which ages to light brown. The others, and the sapwood of poplar, are near white.
To distinguish between these fine-grained woods, you need to recognize subtle differences in figure. Figure is primarily grain orientation, the appearance of which has a lot to do with the way boardsand veneerare cut, but also small distinguishing characteristics such as the flecks in cherry, maple and beech.
Mahogany could be classified as an exotic wood because it grows in jungle areas. But
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