Table 1.
Overview of the tested adhesive recipes.
Fig 1.
Schematic of standardised wood lap shear test specimen.
Side and top view of test specimen composed of two adherends adhesively bonded together in the centre (bondline).
Fig 2.
Sample in lap shear test apparatus.
Clamps of a Zwick-Roell 1455 tensile bench containing standard adhesive lap shear test specimen with arrows indicating the applied direction of force.
Fig 3.
Idealised example of stress/strain curves.
Curves for two different materials displaying brittle and ductile failures. The elastic region is the linear part of the curve, and any displacement along this section is temporary. The plastic region occurs after, and displacement here is permanent.
Fig 4.
Cross section of impact test set-up.
Cross section showing the direction and point of impact just above the bondline (adhesive layer) and steel reinforcement of the impact specimen.
Table 2.
Overview of lap shear results.
Fig 5.
Relative stiffness of beeswax and beeswax-ochre containing adhesives.
Boxplot displaying how the stiffness (N/m) of three different rosin-beeswax adhesives is affected by the addition of 100 mg ochre. Adhesive recipes are expressed by the mass of each ingredient (mg).
Fig 6.
Maximum force (Fmax) and displacement at maximum force (DL at Fmax) for each adhesive mixture during lap shear testing. Adhesive recipes are expressed by the mass of each ingredient (mg).
Table 3.
Overview of failure modes and fracture types from all lap shear tests.
Fig 7.
Example of failure modes through examination of the bonded surfaces after lap shear test completion.
Left: cohesive (250 mg rosin/250 mg beeswax/50 mg ochre), the adhesive remains evenly bonded to both sides; middle: mixed-mode (400 mg rosin/100 mg beeswax/100 mg ochre), the adhesive favours one side, but remains bonded to both some areas; right: adhesive failure (400 mg rosin/100 mg beeswax/50 mg ochre), the adhesive remains bonded to one side only.
Table 4.
Overview of impact test results.
Fig 8.
The logarithmic y-axis represents impact resistance in Joules for each recipe. Adhesive recipes are expressed by the mass of each ingredient (mg).
Fig 9.
Photograph showing bonded surfaces of wood adherends with 100% acacia gum after the impact tests.
All specimens exhibit some form of substrate failure, though some are more severe than others. The arrows point to areas where the wood failed but the adhesive remained bonded.
Fig 10.
Comparison of wt% ratios for two different recipes.