Tables of Weights and Measures

Taken from specifications quoted by my suppliers.

All data should be used as a guide only, and not an exact specification.

Fabric weight and thickness

Fabric Metric Equivalent 1 Thickness (imperial) 2 Thickness (metric) 1,2
2.3 oz/yd2 fiberglass
(plain weave cloth)
78 gm/m2 0.004″ 0.10 mm
6.0 oz/yd2 fiberglass
(plain weave cloth)
203 gm/m2 0.007″ 0.17 mm
5.0 oz/yd2 Kevlar (TM)
(plain weave cloth)
170 gm/m2 0.010″ 0.25 mm
5.8 oz/yd2 Carbon Fiber
(plain weave cloth)
197 gm/m2 0.009″ 0.23 mm
9.0 oz/yd2 Carbon Fiber
305 gm/m2 0.011″ 0.28 mm

1 calculated values, approximate.

2 dry fiber thickness – to obtain total layup thickness, sum the dry fiber thickness of each individual layer, and then multiply by a weighting factor for laminated thickness; this factor may be greater than 1 for a hand layup, and less than one for a vacuum-bagged layup. Finally, add the estimated thickness of any final epoxy topcoat or paint.

For a simple layup of one layer of 6oz ‘glass and one layer of 2.3 oz ‘glass, with a topcoat of epoxy, you can safely assume a skin thickness of 0.5 mm per side, for a total of 1mm added to the overall thickness of the foil. This will be correct within any reasonable fabrication tolerances.

Wood Density and Strength

Species Specific Gravity Density @ 8% Moisture Density @ 12 % Moisture Modulus of Elasticity @12% Compressive Strength @ 12%
Western Red Cedar 0.33 356 kg/m3
22 lb/ft3
369 kg/m3
23 lb/ft3
7,700 MPa
1,110,000 psi
31,400 kPa
4,560 psi
Sitka Spruce 0.42 454 kg/m328 lb/ft3 470 kg/m329 lb/ft3 9,900 MPa1,570,000 psi 35,700 kPa5,610 psi
Alaskan Yellow Cedar 0.46 497 kg/m331 lb/ft3 515 kg/m332 lb/ft3 9,800 MPa1,420,000 psi 43,500 kPa6,310 psi
Douglas Fir 0.50 540 kg/m334 lb/ft3 560 kg/m335 lb/ft3 12,600 MPa1,790,000 psi 47,600 kPa6,900 psi
Phil. Mahogany 0.54 583 kg/m336 lb/ft3 605 kg/m338 lb/ft3 11,200 MPa1,630,000 psi
White Ash 0.63 680 kg/m342 lb/ft3 705 kg/m344 lb/ft3 12,000 MPa1,740,000 psi 51,100 kPa7,410 psi
Core-Cell LP1200 200 kg/m312 lb/ft3 200 kg/m312 lb/ft3 42,441psi??? 500 psi

Compiled from various sources found online, may contain errors. There is variability from tree-to-tree and even plank-to-plank within each species.
8% Moisture Content is typical of kiln dried lumber.
12% Moisture Content is typical of air dried lumber.
Compressive strength measured is parallel to grain.