Study on the Effects of Sanding on the Strength of the Adhesive Joints

In this paper, the surface roughness obtained from sanding was studied and its effect on the shear strength of single-lap adhesive joint was examined. 2024-T3 aluminum sheets were cut into standard pieces and then sanded with seven sandpapers. Pairs of prepared surfaces were attached using two-part Araldite 2015 adhesive with a high viscosity and HPL1012/HPH112 epoxy with a low viscosity. Results show that the ultimate shear strength initially increases and then decreases as surface roughness is increased. The optimum surface roughness is not the same for both high and low viscosity adhesives, which shows the dependency of this method on the type of adhesive. The maximum ultimate shear strength for Araldite 2015 adhesive joints was obtained for sanding with sandpaper number 400 with 0.3 μm surface roughness and was equal to 12.98 MPa. The maximum ultimate shear strength of Epoxy HPL1012/HPH112 adhesive joints was obtained for sanding with sandpaper number 120 with 0.35 μm surface roughness and was equal to 5.02 MPa.