There are several steps to consider in the process of edge-gluing lumber including (1) lumber selection, (2) cutting to rough length, (3) ripping, (4) jointing, (5) grain matching, (6) biscuit joining, (7) gluing, (8) clamping and (9) thickness sanding. Just how you go about these steps depends on the condition of the lumber, the capacity of your machinery and the final size of the glue-up.
If at all possible, try to have all boards in the glue-up out of the same tree. If that is not possible, select lumber that is of similar color and grain pattern. To my mind, the ideal glue-up looks like one, extremely wide board with the glue joints barely visible to the naked eye. Since this only an ideal, I always try to get as close to it as possible.
Another, less-important goal would be to have all boards in the glue-up of the same approximate width. I am not suggesting ripping the wider boards down to match the narrowest board as this would be a terrible waste of expensive lumber. I do suggest, however, ripping extremely wide boards in two to minimize the possibility of curling due to changes in humidity after delivery.
Straight or ribbon grain makes the best homogeneous final appearance while wavy or swirly grain makes for an interesting but more difficult glue-up. Swirly grain will require orientation of the individual boards to minimize the number of places that the grain line suddenly stops at the glue line rather than appearing to continue into another swirl in the adjacent board. This orientation is highly subjective.
CROSS-CUTTING TO ROUGH LENGTH
I always rough-cut my lumber into lengths an inch longer than the length of the final product. This allows the entire glue-up to be neatly trimmed to size after the glue is dry. It also makes the ripping and jointing process a lot easier as I will explain below. The same is true for the width of the glue up: Make sure it is about an inch wider than the final product after trimming.
Kiln or air-dried lumber often decides to bow into a curve as it dries and this must be corrected before a glue-up can be accomplished. If my finished glue-up is only 3 feet long and it is coming out of a 14-foot bowed board, it will be far easier and economical to get the curve out of the 3-foot pieces than it would to remove the curve from the entire 14-foot board before cross cutting. This is one reason that you should always do your rough cross-cutting before ripping and jointing. Another reason is that a 14-foot, 2″ thick x 12″ wide board is pretty difficult to control on a jointer or table saw.
If there is a bow in one or more of your mesaproducts rough-cut pieces, those pieces should first have the curved edges ripped off on the table saw. The concave side of the board should always be towards the fence. Measure from the fence out to the outside of the end of the board that is nearest the fence and set the fence to cut this width. Once you have trimmed off the convex side of the board, flip it over side-to-side and find the point where the outer edge of the board is closest to the fence (somewhere near the middle) and rip the board to that width. When all boards have been ripped straight, take them to the jointer.
The jointing process should now be fairly easy in that the boards have been ripped straight. Take shallow depth cuts to minimize the possibility of tear-out. In loose-grained lumber with a lot of swirls on the face side, tear-out is sometimes unavoidable. If this happens, try running the board over the jointer head in the opposite direction. If the tear-outs persist, you will have no other option than to rip the tear-outs away on the table saw. You will then have a sawn edge in your glue-up. If you have a clean-cutting table saw blade like a recently sharpened Forrest Woodworker II, this should not be much of a problem, especially if you plan on using a biscuit joiner to secure your glue-up. You probably won’t be able to tell which glue lines are jointed and which are ripped in the final product.