There are several procedures to ponder in the process of edge-gluing wood 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.
WOOD SELECTION:
If at all possible, try to have all wood in the glue-up out of the same tree. If that is not possible, select planks that are of similar color and grain pattern. To my mind, the ideal glue-up looks like one, extremely wide plank with the glue joints almost invisible to the naked eye. Since this only an objective, I always try to get as close to it as possible.
Another, less-important objective would be to have all planks 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 reduce the possibility of curling due to changes in humidity after delivery.
Straight or ribbon grain makes the best homogenous final appearance while wavy or swirly grain makes for an interesting but more difficult glue-up. Swirly grain will require organization of the different wood 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 plank. This orientation is highly subjective
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 has cured. It also makes the ripping and jointing process a lot easier as I will explain below. The same is true about the width of the glue up: Make sure it is about an inch wider than the final product after trimming.
RIPPING
Kiln or air-dried planks 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, 1-inch pieces than it would to remove the curve from the entire 14-foot plank 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, 2ý thick x 12ý wide plank is very difficult to control on a jointer or table saw.
If there is an arc in one or more of your rough-cut pieces, those parts 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 ripped off the convex side of the board, flip it over side-to-side and find the point where the outer edge of the piece of wood is closest to the fence (somewhere near the middle) and rip the plank to that width. When all wood have been ripped straight, take them to the jointer.