Updated: Apr 22, 2022
"Stack Lamination is a process in which flat boards are precut to shape, then both face-and edge-glued in such a manner that an overall form, with the grain running the same direction, can be built up. The resulting shaped, yet rough-surface mass is then further refined by carving and finishing".*
The stack lamination process described in Wendell Castle's quote above is the technique I used for earlier work and is brutishly labor-intensive. After each layer or lamination is glued to the one below, the top surface of the newest layer must be hand-planed perfectly flat after the clamps are removed. The hand planning can take a few minutes to over an hour, depending on how flat the top surface remained from the glue-up process.
I've since developed a machine-dependent stack lamination process from the one described above. I glue each complete layer to its precise shape and wall thickness, usually 2-1/2" to 4". I then joint one side of the lamination flat on a large jointer, then rough size it to within 2mm of its final thickness with a large planer. The last step is feeding the lamination through a wide belt sander that maintains a thickness and flatness to a few thousand, eliminating hand planning.
This machine-intensive stack lamination method enables more completed layers per day while maintaining the flatness of each layer to within a few thousand. This approach has about 15% more waste but is about 15% to 20% faster than Castle's process. It's a wash as far as time and material.
If I was starting over and younger, I'd design the process around CNC equipment and robotic arms as some young oversea woodworkers are doing. Yet another arms race!
*The Wendell Castle Book of Wood Lamination, Page 88, Wendell Castle & David Edman, © 1980 Littleton Education Publishing