Wood

(SW) = Soft Wood: Cedar, Cottonwood, Pine, Redwood
(HW) = Hard Wood: Ash, Beech, Birch, Cherry, Mahogany, Maple, Oak, Poplar, Teak, Walnut
(CW) = Composite Wood: MDF, Soft Plywood, Hard Plywood
(LW) = Laminated Wood: Laminated Chipboard, Laminated Plywood
Plastic

(SP) = Soft Plastic: ABS, Polycarbonate, Polyethylene, PVC, Polypropylene, HDPE, Polystyrene, UHMW, Extruded Acrylic
(HP) = Hard Plastic: Cast Acrylic, Melamine, Nylon, PVC, Vinyl
Aluminum

Non-Ferrous Metals
Composite

(C) = Composite: Carbon Fiber, Fiberglass, Phenolic
Honeycomb

(HC) = Honeycomb: Honeycomb Core, Aircraft Panel
Foam

(F) = Foam: Polyurethane Foam, Polyethylene Foam