A tool for forming a panel including a core area, at which plies sandwich a core, and a trim area surrounding the core, at which the plies are bonded together, is provided and includes a body having a surface on which the panel is formable, an assembly to apply bonding pressure to the plies at least at the core and trim areas and a clamping device external to the assembly to apply a clamping force to the vacuum bag and the plies.