Replacing the bridge plate used to be the only way to flatten a top. This tool will reduce, and in many cases, eliminate the common belly behind the bridge. The guitar will retain its full original value and the luthier can avoid the time-consuming task of attempting to carve the bottom of a new bridge to conform to a distorted top. The kit includes two precision-machined aluminum bridge-shaped (convex) cauls and three common bridge plate (concave) shapes.
If you don’t have a hide glue pot, you can submerge cauls in hot water (about 150 degrees) before use. Dampen the bridge area and the entire bridge plate. Install bridgeplate caul with concave side up; hold in place while you install the bridge caul with convex side down. Magnets will hold cauls in place while you install clamps. Clamp with at least as much clamping pressure as you would use to affix the bridge. Leave overnight or longer, depending on the severity of bulge. The convex surface of bridge caul can also be used to flatten cupped wings of an old bridge before regluing.