Remove the old bar top to create the bigger bar surface by removing bolts inside the cabinetry. Remove the backplash and all fixtures to exposure the cabinet base.
Place the original countertop directly on a sheet of 3/4-inch medium-density fiberboard, larger than the original top, to trace the original shape. Add a rectangular or curved bar overhang in the drawings to make a bigger footprint.
Raise the fiberboard to be cut by using 2-by-4-inch boards underneath. Cut the blanks with a circular saw and a jigsaw. Use a metal straightedge as a cutting guide for long edges. Cut curved edges or insets for a sink with a jigsaw.
Butt together pieces of fiberboard edges after gluing them. Use clamps to hold it until the blanks dry as a solid piece.
Trace dimensions of the fiberboard to the laminate material. Leave an overhang around all sides of 1 inch as you draw the shape. Cut laminate panels, including all edging for the bar space covered in laminate. Use a carbide-tipped scoring knife to score the laminate so you can break the pieces at score lines.
Brush two coats of adhesive on the surfaces of fiberboard that you will laminate. Apply a coat of adhesive to the laminate. Start with the edging pieces of laminate and put them aside. Brush adhesive on larger laminate panels, as well. Allow the adhesive to dry to a tacky state.
Use a J roller to press the laminate to the fiberboard. Allow to dry thoroughly. Use a trimmer router to trim all of the edges of the laminate, holding the trimmer flat against the laminate. Use this technique on all top surfaces of the bar countertop.
Attach countertop material to support brackets on the counter with screws. Place stools to fit underneath the new bar space.