I do restoration work that often requires gluing on odd-shaped pieces such as moldings and carvings.
I discovered that scraps of Styrofoam serve as great clamping cauls for pieces that lack flat clamping surfaces. Just cover the part to be clamped with waxed paper or cellophane, and then lay a piece of Styrofoam about 1" thick over it, topped with a wooden caul for support. Under clamp pressure, the Styrofoam will compress over the part, providing fairly consistent pressure overall. This technique works not only for moldings and carvings, but also for inlay repairs where the patch might initially be a bit thicker than the underlying area.
