[D.1] WOOD AND WOOD FINISHES (copy)

Timber

Uncut log; not yet usable for construction

Lumber

Timber sawn or split in the form of beams, boards, joists, planks. Material bought in the hardware store

Softwood

Any light, easily cut wood; cone bearing or coniferous; needle-leafed, usually evergreen trees

Hardwood

Any tough, heavy timber with a compact texture; any deciduous or broad-leafed tree (any tree that loses its leaves annually). Dominant feature is its presence of pores or vessels

Parts of a Tree Trunk

Pith

Part of a tree trunk; hardest part of a tree; center or core

Heartwood

Part of a tree trunk; older, darker part of the trunk surrounding the center of the log

Sapwood

Part of a tree trunk; younger, light-colored wood just beneath the bark of the tree

Earlywood

Part of a tree trunk; spring wood; lighter and lower density compared to latewood

Latewood

Part of a tree trunk; summer wood; darker and more dense

Medullary Rays

Part of a tree trunk; brings nutrients and water to the tree

Natural Drying

Commonly called air-drying or sun-drying. Lumber is strip-piled at the slope on a solid foundation to allow air to circulate around every piece while sloping allows water to run off quickly

Kiln Drying

Places the stacks of sawn timber in a kiln, to reduce the moisture content in wood, where the heat, air circulation, and humidity is closely controlled

S1S

Surfaced one side; used for framing

S2S

Surfaced two sides; used for framing

S4S

Surfaced four sides; often used for parts with exposed sides and carving details

Nominal Size

The size of lumber when it is cut from the log; before it is planed down to s1s, s2s, s4s

Actual Size

Dimensions of lumber after it has been dressed or surfaced

Board Foot

A unit of measurement for lumber that equals 1'' x 12'' x 12”; refers to the nominal size of a dressed lumber

Straight Grain

Fibers running in the same direction as the main axis of the tree

Inter-locked Grain

Grains are in successive layers and in opposite direction

Wavy or Curly Grain

Constantly changing in orientation so that a line drawn parallel to their direction appears as wavy lines

Plain/Tangential or Flat Grain

When wood is cut parallel to the grain direction and tangent to the growth rings

Quarter or Radial Grain

When board is cut parallel to the grain direction but through the radius of the growth rings

End Grain

When board is cut across the grain (perpendicular to the grain direction and the growth rings)

Plain Sawing

Method of sawing lumber; the most common method because it produces the highest quantity of usable lumber. Shows flat grain on their faces and quarter grain on the edges

Quarter Sawing

Method of sawing lumber; cuts the log quarters then slices each quarter into boards. Shows mostly quarter grain or their faces and flat grain on the edges

Live Saw

Method of sawing lumber; sometimes called sawing through and through. Shows mostly mixed grain; flat grain near the center of the face and quarter grain near the edges

Natural Wood Defects

Acquired defects in wood occasioned by seasonal checks, insect, and fungal attack

Artificial Wood Defects

Defects caused by incorrect sawing and seasoning

Knots

Natural wood defect; basal stumps of incipient or cast-off branches in the living tree

Pin Knots

Grade of knots; small knots 1/2” (12.5mm) or under, caused by the shedding of early branches. Usually allowable in prime timber

Spike or Splay Knots

Grade of knots; knots sliced through their length during sawing, and commonly known as “slash” knots

Encased Knots

Grade of knots; dead knots which are still sound and difficult to dislodge, often ringed with resin in softwood

Branched Knots

Grade of knots; two or three knots springing from a common center

Shakes

Natural wood defect; the medullary ray and springwood cells of ring-porous hardwoods are weaker than the remainder, and built-in tensions are created which tend to level out, either in the growing tree under certain adverse conditions or in the felled tog during seasoning. Thus extensive splitting may occur in the weakest links

Radial Shakes

Form of shakes; log splits from the pith or heart radially along the medullary rays, usually indicating that the tree has passed its prime

Frost Shakes

Form of shakes; project inwardly from a definite frost rib on the cambium and is the result of severe weather

Tangential Shakes

Form of shakes; the soft springwood splits away from the harder summerwood either during seasoning or through shearing stress

Cross Shakes

Form of shakes; caused by compression and not by splitting or shearing, while the actual rupture is across the grain and not with it as with all other shakes

Pitch Veins or Pitch Pockets

Natural wood defect; sometimes known as resin pockets, they can appear either as thin veins or shallow cavities filled with resin. Usually caused by damage to the cambium layer

Pitch Flecks

Natural wood defect; repeated damage to the cambium layer by small insects is often healed over with hark and may show small dots or patches of brown cork deeply buried in some woods, notably birch alder and sycamore

Rind Galls

Natural wood defect; patches of ingrown bark caused by exterior damage to the growing tree

Internal Sapwood

Natural wood defect; the wood usually separates and breaks away along the ring during conversion

Burls or Burrs

Natural wood defect; caused either by fungal or insect attack irritating the cambium layers or by small twigs which fail to develop owing to insufficient nourishment, forming a dense mass

Callus

Natural wood defect; tissue formed over a wound in a tree resulting in unnatural growth incorporated in the normal wood growth

Canker

Natural wood defect; caused by fungoid disease

Catface

Natural wood defect; a partially heated fire scar

Cupping or Rounding

Artificial wood defect; the plank hollows across the width, forming a rounding on the underface, often due to incorrect piling

Bowing

Artificial wood defect; the plank is curved like a bow throughout its length

Springing

Artificial wood defect; sometimes known as edge bend. The wood remains flat but bends edgewise on its own plane

Twisting

Artificial wood defect; the plank twists on its longitudinal axis with the result that the long edges are straight but the diagonals are curved. Known as “in winding”

Warping or Casting

Artificial wood defect; synonymous terms for distortion in one or more directions

End Splitting

Artificial wood defect; the butt end of the plank splits open, usually caused by too rapid drying, but some species will always split

Sun Checking

Artificial wood defect; the wood surface is covered with small splits along the grain caused by too rapid drying in hot sun

Flaking

Artificial wood defect; the surface of the wood lifts in innumerable small flakes or layers which spring under the cutting action, preventing a smooth surface

Diagonal Grain

Artificial wood defect; the grain runs obliquely to the longitudinal axis, usually due to incorrect sawing

Case Hardening

Artificial wood defect; if the wood dried too quickly then the surfaces dry out at a rate quicker than the rate of movement of moisture by capillary attraction from the plank

Honeycombing

Artificial wood defect; if the KD of the case-hardened timber is continued to dryness then the natural shrinkage movement of the moist interior as it dries will be locked in by the rigid outer skin, resulting in sever internal stress and subsequent disruption of the wood fiber, not visible from the outside

Collapse

Artificial wood defect; characterized by extensive shrinking and warping, particularly in springwood, giving a washboard effect

Wood Finishes

These are applied to wood for its protection and to enhance grain structure or alter its wood application

Transparent Finishes

Emphasize and enhance the charm of natural wood color and grain

Penetrating Finishes

Soaks into the wood pores to give a natural look and feel

Surface Coating

Seals wood pores for protection against water and other destructive elements

Clear Lacquer

Made from resin dissolved in ethyl alcohol; it forms a high gloss film on the surface when dried

resin + ethyl alcohol

Varnish

Gives relatively hard, tough and elastic finish

resin + oil

Shellac

Spirit varnish, made by dissolving purified lac flakes in denatured alcohol

lac flakes + denatured alcohol

Oil Stain Finish

Finish using boiled linseed oil and various other oils

Polyurethane Finish

Transparent plastic finish. Very tough, hard and flexible finish. Has superior resistance to chipping, abrasion and dirt retention; used in flooring

Wax or Films

Achieved by brushing, rubbing or spraying processed fatty acids from animals and vegetables, mineral sources combined with alcohol

Wood Stain Finish

Dyes or pigments suspended in water or oil. it alters coloring the wood or accentuates its natural color without covering the grain

Bleach Finish

Lightening the wood color achieved by applying one of the various acids and chlorine compound pertained to as bleaching agents

Chlorinated Laundry Bleach

Comparatively weak, excellent for removing chemicals, dyes, ink and water stains from wood surface if used full strength

Oxalic Acid

Best bleach to use not only on natural wood colors but also on many water and chemical stains

Two-solution Bleach

Fairly expensive and extremely strong. Brings out light tones on dark wood

Opaque

Gives a solid finish for protection and decoration

Paints and Enamels

A mixture of a solid pigment suspended in a liquid vehicle

Pigment

A finely ground, insoluble substance suspended in a liquid vehicle to impart color and opacity to a paint

White Pigment

Pigment; either white lead, oxide, lithophane or titanium

Colored Pigments

Pigment; derived from minerals or clay

Extenders

Pigment; whitting, talc, and silica

Vehicles

A nonvolatile fluid in which the solid body material is suspended

Drying Oils

Vehicles; linseed oil, tung oil, soybean oil, or fish oil

Thinners

A volatile liquid used to dilute paint or varnish to the desired or proper consistency for ease in application

Driers

Added to the paint to accelerate the oxidation and hardening of vehicle

Fanciful Finishes

Effects such as antique finish, crackle or crazed finish, wrinkle finish, and others