I have a 2’ wide glue-up table that I made. I made these clamping cauls specifically for this table. Unfortunately, my table top is a 1 ½” thick Formica countertop that I had. I found that, when clamping the caul down tight, if I made the cauls out of a hard wood or made the arch too pronounced, the sides of the Formica countertop would pull up with the excess pressure. So make sure your glue-up table top is plenty rigid.
To start off, I ripped a 2” wide length of pine, and drew an arch on the pine wood. Then with a bandsaw, I carefully cut the arch. No matter how good you are with a bandsaw, it won’t have a perfectly smooth arch when you’re done.
To correct this, I clamped a piece of steel, on a mounting board, that hugged the arch on the pine. This steel became the form for the pattern bit on my router.
With the bearing riding on the stiff steel, the end result on the arch of the caul is a smooth consistent curve.
This results in even pressure for the full 2’ width of the glue up table.