SOLAS Wood Manufacturing & Finishing flashcards
SOLAS Wood Manufacturing & Finishing · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Equilibrium moisture content
- The moisture content wood reaches when it neither gains nor loses water to the surrounding air, determined by ambient relative humidity and temperature at a given time.
- Fiber saturation point
- The moisture content at which cell walls are fully saturated but free water is absent, roughly 28–30% for most species; above it, strength and dimensions stay nearly constant.
- Tangential vs radial shrinkage
- Tangential shrinkage across the growth rings is roughly twice radial shrinkage, which is why flat-sawn boards cup and distort more than quarter-sawn boards during drying.
- Case hardening
- A drying defect where the outer shell is set in tension and the core in compression; a prong test on a cross-section cups inward toward the original surface.
- Reverse case hardening
- A drying stress pattern where the core is wetter and the case drier in an inverted sense, shown by a prong test cupping outward, often from over-rapid early drying.
- Honeycomb checking
- Internal cracks along the rays near the core, caused by tensile stress when the wet core shrinks after the case has already hardened during kiln drying.
- Wet-bulb depression
- The difference between dry-bulb and wet-bulb temperatures in a kiln; it sets the drying rate and evaporation demand on the lumber charge.
- Kiln schedule
- A table of dry-bulb and wet-bulb temperatures staged by moisture content and species, limiting the depression so drying stress stays below the checking threshold.
- Quarter-sawn lumber
- Lumber cut so growth rings meet the wide face at roughly 45–90 degrees, giving more stable dimensions, less cupping, and prominent ray fleck in some species.
- Flat-sawn lumber
- Lumber cut with growth rings roughly parallel to the wide face, producing the cathedral grain figure but greater cupping and tangential shrinkage movement.
- Grain tear-out
- Surface defect in planing or moulding where knives lift and break fibers running against the cut direction, worst around knots and reversing grain.
- Snipe
- A gouge or dip at the leading and trailing ends of a machined board, caused by cutterhead overhang when the feed rolls lose contact with the stock.
- Chatter marks
- Regular ripples across a machined surface from vibration, often due to dull knives, excessive feed speed, or inadequate hold-down pressure.
- Rough mill allowance
- Extra thickness and width left on stock (typically 3–6 mm) to be removed after moisture conditioning, allowing for warp and final surfacing.
- PVA adhesive
- A water-based polyvinyl acetate glue suited to interior joints in dry conditions; it creeps under sustained load and softens with heat and moisture.
- Resorcinol adhesive
- A two-part formaldehyde-resorcinol glue forming durable exterior-grade joints; it cures at room temperature and tolerates moderately high moisture content.
- Polyurethane adhesive
- A moisture-curing one-part glue with good water resistance, useful for exterior joints; it foams slightly and needs clamping pressure to close gaps.
- Clamping pressure
- The force applied across a glued joint; too little leaves a thick glue line and weak bond, too much starves the joint of adhesive.
- Sticker marks
- Discolored or indented bands on dried lumber where kiln stickers contact the boards, caused by uneven airflow or wet stickers.
- Sticker spacing
- The interval between kiln stickers, typically 300–600 mm along the length, chosen to support boards and maintain uniform airflow through the stack.
- Air-drying stack
- An open pile of lumber on stickers and bearers, oriented for prevailing wind, used to bring moisture content down before kiln drying or final machining.
- End coating
- A wax or sealer applied to board ends to slow end-grain drying, which otherwise dries much faster than the faces and causes end checks.
- End checking
- Cracks at board ends from rapid drying of exposed end grain, prevented by end coating and by controlling the early kiln schedule.
- Surface checking
- Shallow cracks on the face of lumber from tensile stress when the surface dries and shrinks faster than the core can follow.
- Moisture meter correction
- Pin meters read low on wet or treated wood and high on some species; readings are corrected for species and temperature using the meter's published tables.
- Oven-dry method
- The reference moisture content test: weigh the sample, dry it at about 103 degrees Celsius to constant weight, and compute loss as a percentage of dry weight.
- Sandpaper grit sequence
- Successive grits should roughly double or step by about 50% (for example 80, 120, 180, 220), removing the previous scratch pattern before moving finer.
- Sanding sealer
- A thin fast-drying coat applied before finish sanding to stiffen surface fibers so they cut cleanly and to reduce absorption of the topcoat.
- Raised grain
- Swelling of cut wood fibers after waterborne finish or water-based stain is applied; controlled by pre-raising with water and sanding back before coating.
- Finish film thickness
- Total dry film build, usually measured in micrometers or mils; too thin gives poor protection and too thick risks cracking, so follow the manufacturer's wet and dry film spec.
- Sealer vs topcoat
- A sealer bonds to the wood and provides a sandable base; a topcoat provides the wear and moisture barrier, so they are formulated and applied for different roles.
- Wet film gauge
- A comb or wheel gauge used immediately after coating to check wet film thickness, which converts to dry film thickness using the coating's volume solids percentage.