—Kris Papke,
Stockton, CA
The culprit is likely that the press isn’t exactly flat because it’s not on a dead-flat surface. Any cup or twist in that will reflect in your final product. To ensure a dead-flat press, build a dead-flat torsion box.
A torsion box is made up of a grid of cross-members sandwiched between two exterior skins. Once glued up, the skins and core create a unit significantly more rigid than the individual components and more likely to stay flat.
To build a torsion box, you need a level platform. Construct a temporary assembly table by laying sturdy beams across a pair of saw horses and leveling them with shims. Use a 6' builder’s level or laser level to ensure the beams are perfectly coplanar. Take your time getting this part right. Once your assembly platform is flat and level, place one of the outer skins on the beams, and assemble the inner grid using brads and glue. It’s not super critical that the spacing be exact. When the grid is complete, glue, brad, and screw a 1/2" skin on top, then flip the whole thing over and repeat for the other side. Give the glue time to dry before moving your torsion box from the level assembly platform. Once the glue has cured, it will stay flat.
Starting your veneering process on a flat surface is the first step to ensuring perfectly-flat panels.
Owain Harris is an award-winning custom furniture designer and builder from Gonic, NH.