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 (unidirectional) |
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.