The results? It worked! I think I will keep this vacuum press.
I did the following using new shop-resawn veneers; previously resawn panels will be used for the doors (i.e, the “wing”, and “Don Quixote”). Before doing any serious work with the vacuum press I wanted to assure myself it worked properly, and that I was indeed familiar with the process. The system did the job well. But not all was perfect, as you will learn toward the end.
Now, some details of the first veneer panel done with the vacuum press:
As I did the quality control of this first veneered panel I noticed a slight bow as I sighted down the top and bottom edges. To measure the amount of the bow, I placed the panel flat, with the concave spalted maple side up. With a straight edge placed across the surface I measured 0.030″ concavity (this is 30 mils, or 30 thousands of an inch).
I was puzzled about this amount of distortion, as I expected the veneered panel to be perfectly flat. One obvious area to look was the platen I fabricated, and showed earlier:
In retrospect, I now feel that the platen should not extend too far beyond the edges of the package being pressed. This is especially true if the “sandwich” is thick, as this one was (about 4 inches). I now believe what happened was that the outer edges of the platen lifted slightly during the time that vacuum was on, lifting them and causing the slight deflection I measured.
I must run one additional test, to determine if my thinking is correct. That is, unless anyone reading this can confirm my theory in the next 16 hours or so. I would appreciate your feedback, especially if it will save me doing another test glue-up.
The bottom line of this test: I achieved absolutely perfect adhesion, with no gaps anywhere along the visible glue line between the veneer panels and the substrate. In addition, the entire surface of the veneers is perfectly flat, totally free of bubbles or areas of poor adhesion.