When you saw brace wood out of a board the wood fibers can (often) not run parallel to the faces of the brace. This is called ‘runout’. Under stress a brace with runout will tend to crack along the wood fiber lines, which are across the brace. If one looks at guitar repair videos where braces are being fixed, the crack is almost always across the brace, due to runout.
I have some nice sitka spruce boards which are nicely quartersawn which means that the growth rings are up and down in the board, ‘vertical grained’ which is what one wants for a brace. However, a little experiment demonstrated that the wood fibers did not run parallel to the face of the board.
As a way to make a stiffer, more stable brace I decided to saw this up into thinner strips and then laminate them together, alternating direction, to eliminate the runout problem. At the same time I decided to laminate them with a 15 foot radius curve which is what I use for back braces. That way I do not have to further process the brace to add the curved face.
I made a simple gluing block and laminated with a pre-catalyzed modified dry powder urea glue. This glue dries very hard, and once set is impassible to soften with water or heat. The perfect stuff for laminations that one never wants to take apart. I glued up some sections and then sawed the sections into brace stock. They held the 15 food radius well and seem very stiff which is good.
