In studying/testing ways to structural bond aluminum sheets (project goal is to structurally bond a hydro formed two axis corrugate/honeycomb inner skin to a formed surface skin) test samples are showing inconsistencies in bonding. Testing is so far limited to resistive spot welding and I believe the combination of surface oxidation layers resulting in electrical resistance and the high thermal conductivity of aluminum are combining to produce inconsistent strengths in the weld areas. Mechanical abrasive removal of the surface oxidation layer has produced inconsistent results. I’m hoping there is some applied practice (chemical treatment?) to produce consistent results that can be applied in a roller seam weld system?