Pull the edge of the peeling Formica away from the surface gently to access the space behind. Prop it away from the surface wit a wooden dowel or pencil.
Apply lacquer thinner or acetone from a plastic squeeze bottle onto the face behind the Formica and back of the Formica. Allow this to work on the adhesive for 30 seconds to soften it.
Scrape the softened adhesive from the back of the Formica and the surface behind with a flexible putty knife. Wipe the used adhesive from the putty knife with a clean rag dampened with acetone.
Leave the dowel propping the piece away from the surface to allow the surfaces to dry completely to prevent the new adhesive from being softened.
Apply a medium-heavy coat of contact cement on the back of the laminate and the surface behind the laminate, using a small paintbrush.
Adjust the setting on your heat gun to medium and blow warm air behind the loose laminate for 15 to 20 minutes until the contact cement is completely dry to the touch.
Remove the dowel from behind the loose laminate and press the laminate down, so that the two glued surfaces meet. Press the laminate into place with a J roller, working from the inside out.
Pound along the outside edge with a rubber mallet to seal the laminate fully and press out any excess air underneath it.
Use the acetone-dampened rag to remove any excess contact cement from the face of the laminate. Double-check the edges of the laminate to ensure that the edges are fully pressed down, once the excess glue is removed, and tap it in place with the mallet if needed.