Question - Our Formica kitchen countertop is glued onto a fir plywood backing. Over the years, the contact cement has let go in spots. Formica is also glued tightly along the edges. Can a glue be injected between the Formica and the plywood to reglue them, even though old contact cement is still there?
Answer - Your countertop is probably loose because someone periodically places a hot pot on it. When the temperature goes above 150 degrees Fahrenheit, the contact cement softens and starts to let go. If the contact cement is not too old, it may be reactivated by heating the area with a gun-type hair dryer. You need a temperature of about 200 degrees Fahrenheit on the surface of the Formica to reactivate the cement. Then roll the area with a hard rubber roller and cover it with a board clamped in place or weighted sufficiently to hold it in place and the contact cement resets.
If your contact cement is aging and cannot be reactivated, you can bore a tiny hole into the unstuck area from the underside of the plywood. Take special care to bore deeply enough to penetrate the plywood but not far enough to come through the Formica. Inject white wood glue into the unstuck area. Then, push the loose section of the countertop up and down to spread out the glue. As before, cover the area with a board clamped or weighted to flatten the Formica until the glue dries completely.
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