Gluing "Oily" Woods
Cleanliness is the most important factor in bonding success. In all cases, joining surfaces must be clean and free of grease, oil, wax, dirt, or other contaminants. Typically, I would recommend using a freshly machined surface, and wiping it with a solvent just prior to gluing. Wipe the mating surfaces with clean white cotton rags soaked with solvents such as acetone, lacquer thinner, or other water free solvents. Immediately wipe dry with a clean, dry, white cotton rag to pick up oily residues. Repeat if necessary, or until wood appears "dry" or lightens in color. Apply adhesive* as soon as possible after cleaning**.* Epoxies & Polyurethanes (Gorilla Glue, 3M #5200/4200 etc work well ...** It's important to know that the oils will eventually leach out to the surface again.For best results, adhesive should be applied to both surfaces to be glued, and allowed to sit long enough for the wood to soak up as much as it wants, so that when the pieces are assembled the wood will not absorb the glue that would otherwise fill the gap between the pieces, leading to a glue-starved joint. Scarf and butt joints are especially prone to soaking glue out of the joint, as it wicks into the end grain of the wood, (endgrain constitutes the open ends of the hollow cellulose tubes of which the wood is made). Edges of plywood are notorious for soaking up liquids.