11. The third way to achieve in-situ bonding consists of compaction of metal powders together with face sheets . 12. Facing sheets of rain, slippery streets, zones of cobblestone treachery and breakneck sprints, riders have kept to business.13. The goal of in-situ bonding is to create a metallic bonding between the foam core and face sheets . 14. The melting point of the face sheet material is above the melting point of the foamable precursor material. 15. It has proven satisfactory in attaching stiffeners, such as hat sections to sheet, and face sheets to honeycomb cores. 16. Most flush hollow-core doors are faced with plywood with Philippine mahogany, or " lauan " as the face sheet . 17. Ex-situ bonding is achieved by gluing face sheets with an aluminium foam by adhesive bonding, brazing or diffusion bonding. 18. This is difficult to realize as the oxidation of both aluminium face sheets and foam prevent forming a sound bonding. 19. This procedure is successful when steel is used as face sheets instead of aluminium, while the foam core is aluminium. 20. The precursor composition is usually Al-Si, Al-Si-Cu or Al-Si-Mg alloys while the face sheets are 3xxx, 5xxx and 6xxx series aluminium alloys.
