Whether you're painting or simply installing a new sheet of Formica over the old one, you will need to sand the old Formica down. If you are comfortable using power tools, use a handheld belt sander fitted with a 100-grit sanding pad. Otherwise, sand the Formica by hand. You only need to scratch up the surface so the contact cement can form a bond between both sheets of Formica. You do not have to sand if you plan on ripping up the old Formica to completely replace it.
With the old Formica scratched up, you will need to wipe away the dust before installing the new sheet of Formica. Paint contact cement over the top of the counter and on the back of the new sheet of Formica; the cement should completely cover both surfaces. Work with partners to lift the new Formica up and very slowly set it down on top of the counter. Ideally, you should work with one person per side to ensure that the new Formica is perfectly lined up on all sides. Go over the new Formica with a laminate roller to ensure a complete seal.
Painting your laminate or Formica countertop is another viable option for sprucing up your kitchen. Once you've sanded and wiped up the dust, roll on a coat or two of primer and allow it to dry. Apply two to three coats of paint with a roller, allow each to dry before applying the next. Once the counter is painted, apply two layers of clear protective top coat, such as lacquer or polyurethane, allowing drying time between coats. When working with protective sealers, use a soft-bristled paintbrush or a special foam or lamb's wool applicator tool.
Pulling up Old Formica
Removing old Formica and replacing it with new is the most time-consuming way to renovate a countertop. You need thin putty knives to slip under the edges of the old Formica, and lacquer thinner or mineral spirits. The idea is to lift up the Formica as much as you can with the putty knives while applying solvent directly to the old contact cement or other adhesive. As the adhesive breaks down, insert shims under the Formica. Repeat the process, inserting larger pieces of wood until you successfully dissolve the adhesive. Once the old Formica is off, you need to scrape up the glue before installing new Formica.