Biological materials are joined, repaired or fused by heating the material in proximity to a mechanical support. Preferably, the mechanical support comprises a patch or bridge structure. In the most preferred embodiment, the patch is formed from collagen having a thickness from between 2 to 30 mils, and most preferably from 2 to 15 mils thick. Preferably, the patch or support structure contains holes or interlock vias which permit the coagulum to form a mechanical bond therewith, whether preformed or generated by an electrical energy source during welding. The preferred method comprises the steps of: first, placing the patch in contact with the materials to be joined, supplying energy to the tissue in an amount sufficient to form a coagulum at the surface of the patch, and finally, permitting the coagulum to form a mechanical bond with the support or patch. The preferred energy source is an inert gas beam RF energy source, with the preferred gas being argon, and the preferred energy range from about 3 to 80 watts. Support structures are utilized in connection with the welding of collapsible structures.