SOLAS Wood Manufacturing & Finishing cheat sheet

Wood Manufacturing and Finishing

• Moisture content (MC%) = (wet weight − oven-dry weight) / oven-dry weight × 100; equilibrium moisture content (EMC) depends on ambient relative humidity and temperature, so wood moves whenever EMC changes.

• Wood shrinks and swells anisotropically: tangential movement is roughly twice radial; longitudinal movement is negligible (about 0.1–0.2%), so design cross-grain joints with allowance for seasonal movement.

• Rough-mill stock 3–6 mm oversize in thickness and width; final machining to dimension should occur only after the stock has reached the EMC of the service environment (commonly 6–8% for interior work).

• Case hardening shows as a stress-revealing test: a prong cut from a cross-section cups inward if the case is drier than the core; reverse case hardening cups outward.

• Kiln schedule logic: control dry-bulb and wet-bulb temperatures to hold a target EMC; the wet-bulb depression sets the drying rate, and the maximum depression is limited by species and thickness to avoid checking.

• Grain direction governs planing and moulding: feed against the rising grain (knife cuts with the grain) to avoid tear-out; reverse the feed or reduce depth of cut where grain reverses around knots.

• Adhesive selection rule: PVA for interior dry joints, cross-linking PVA or polyurethane for limited moisture exposure, resorcinol or phenol-resorcinol for exterior and structural joints; joint strength depends on close fit, fresh glue, and adequate clamp pressure.

• Machining defect causes: snipe from cutterhead overhang at board ends, chatter from insufficient feed pressure or dull knives, and burn marks from too slow a feed rate or excessive cutterhead speed.