At parity of maximum resistance before failure (in the case of aluminum, deformation), weighs less aluminum or plastic? Let me explain better: if i apply a force of 1000N on one end of a rectangular plate with a fixed fulcrum on other side, beyond this force both materials deforms / break. The plastic will obviously have a greater thickness of aluminum to counter the force. Now, will weigh more the plate of plastic or aluminum? p.s. between all plastics, plexiglass have a good resistance?