Woods of the world

Woods of the World Adhesion Testing

By Tom Pawlak

We recently purchased a 154-piece wood sampler from Eisenbrand Inc., Torrance, California. The 3″ × 6″ × ½” specimens originated from points all around the world. Each specimen was provided with its common name, scientific name, and country of origin. There were several specimens we’ve never heard of.

The PATTI test uses compressed air to pull the stud from the surface. It records the force required to break the bond in pounds per square inch. In all cases tested, the epoxy held and the wood failed.

We thought it would be interesting to find out how well WEST SYSTEM® epoxy adheres to the different wood species. The 3″ × 6″ samples were just large enough to accept two PATTI (pneumatic tensile test instrument) studs. Two results per species does not provide enough data for scientific conclusions, but does give a good idea of what to expect. The samples were prepared for adhesion testing by sanding parallel to the grain with sharp 60-grit sandpaper. No solvents were used to remove any natural oils. All PATTI studs were glued in place using 105 Resin/206 Hardener.

The following results are all woods from Africa and the Philippines. Adhesion results for woods from other parts of the world will be shared in future issues of Epoxyworks. The predominant failure mode for each species was wood failure.

Common name Scientific name Origin Average psi
1 African Wattle Peltophorum africanum Africa 1218
2 Afromosia Afromosia elata Africa 1462
3 Aniegre Aninquera robusta Africa 1564
4 Avodire Turraeanthus africanus Western Africa 1258
5 Black Limba Terminalia spp. Africa 1666
6 Bubinga Guibourtia demueusei Africa 1930
7 Boekenhout Faurea saligna Africa 1544
8 Camphor Cinnamomum camphoratum Africa 1156
9 Cape Blackwood Acacia melanoxylon Africa 1340
10 Ebony, Gabon Diospyros spp. Africa 1564
11 Imbuia Phoebe parosa Africa 1564
12 Iroko Chlorphora excelsa Africa 1299
13 Jacaranda Jacaranda mimosifolia Africa 1462
14 Leadwood Combretum imberbe   Africa 1340
15 Monkey Thorn Acacia galpinii Africa 1258
16 Narra Pterocarpus indicus Philippines 994
17 Olive Olea africana Africa 1605
18 Padauk Pterocarpus soyauxii Africa 994
19 Paldao Dracontomelum dao Philippines 1544
20 Sapele Entandophragma spp. Africa 1198
21 Shedwa Guibourtia spp. Africa 1584
22 Silver Oak Grevillea robusta Africa 1462
23 Silver Terminalia Terminalia sericea Africa 1340
24 Stinkwood Ocotea bullata Africa 1544
25 Syringa Melia azedarach Africa 1218
26 Tambootie Spyrotachys afr. Africa 2033
27 Wenge Milletia spp. Africa 1482
28 White Limba Terminalia amazonia Africa 1034
29 Zebrawood Microberlinia brazzavilensis Africa 1604
A few of the 154 wood samples. These from Africa show a wide variety of colors, grains patterns and densities.

Epoxyworks 21 / Summer 2003