6 Edge-Gluing Tricks for flat, mar-free panels
Making wide boards from narrow ones can be tricky. Ironically, the glue that sticks them together can make clamping a slippery mess, and the clamps themselves may accidentally damage the wood. Here are six tips to nip dings, dips, and dark spots in the bud.
1 To prevent a panel from bowing during glue-up, keep the clamping pressure centered on the edge of the workpiece. For thin stock, use scrapwood supports, as shown above, to raise the panel to the clamp's line of pressure, typically the center of the jaws.
2 An overtightened clamp damages delicate wood, and causes excessive glue squeeze-out and a weakened joint. This often results from counting on your clamps to fix joints that aren't straight and square to begin with. For edge-glued panels, joint the board's face first and then square an adjacent edge to the face. During glue-up, when the joint is closed and even, an additional half-turn on the clamps will give you a consistent, light bead of squeeze-out along the length of the joint, like that shown below.
3 Hardened glue residue on clamps can dent or scratch your workpiece. Clean or replace clamp pads that have stuck-on glue burrs, and wipe down metal surfaces with mineral spirits.
4 When hard metal clamp jaws press on relatively softer wood, metal wins. To prevent denting the wood, use store-bought pads, or adhere cushions to your clamp jaws using hot-melt glue.
5 Wrap waxed paper or painter's tape around clamp bars where they might contact glue. That prevents the glue from reacting chemically with the metal and staining the wood. And you won't have to worry about delicate plywood veneers sticking to the tape or waxed paper.
6 Sharp threads on the ends of pipe clamps can scratch or gouge a workpiece while you position the clamp, especially when you're rushing to stay ahead of the glue's open time. Cover those threads with a tip from a cane or crutch to prevent damage.