I recently had a job fixing a broken slat in a louvered door, and it turned out that the right clamps for the job were sitting in a box at the local office-supply store. As shown in the drawing, I used a couple of binder clips to apply clamping pressure in the right places as the glue set up. The clips were small enough to slip between the slats without distorting them, and they exerted a surprisingly generous amount of pressure.
Christian Petersen, Gaithersburg, MD