Note: Most of the time I use thick, heavy cauls to help align the edges; but not for edge glue-ups of very long boards.
Sometimes I do dumb things, but this one takes the cake — an edge glue-up gone awry by careless pounding with a mallet.
To minimize the risk of damage to the boards, and for large edge glue-ups, I normally use a large, thick piece of similar wood (scrap) to beat the board edges into perfect alignment with the mallet. Meanwhile, I tighten the clamp in that area a little at a time. In a momentary lapse of concentration, I did not use the scrap board; instead, I pounded the mallet directly on the white oak surface (twice!), with these results:
I missed the damage due to lack of contrast after I finished the glue-up, even after a cursory inspection; but it was there:
Too deep to repair by swelling the fibers with water, and applying a hot iron to pull out the crushed fibers, I simply ripped the glued boards at the glue seam, prepared another 75-inch long X 8-inch wide board, and did the glue-up a second time:
The color should equalize quite a bit after the first two coats of dewaxed shellac. And the wonderful medullary rays (“fleck”) will be even more apparent then.
— Al Navas