- Q. When installing stained vertical cedar siding or fascia trim, what type of glue should be used for splices and corners? Some contractors like to dab a little stain on the cut ends of 3-degree splices or on 4-degree corner miters, but is there an exterior glue that will adhere in the presence of an oil-based stain?
A.Jeff Pitcher, vice president of CP Industries, a manufacturer and distributor of adhesives for the wood-products industry, responds: If not for the stain, any exterior wood glue or exterior-grade adhesive would work fine in this application. But oil-based stains could potentially interfere with the glue line, a problem you could avoid by not using any stain on the gluing surfaces. If that isn't possible, use either a solvent-based construction adhesive, such as PL 400 (Henkel, 800/999-8920, www.stickwithpl.com) or a polyurethane-based construction adhesive, such as Chem-Calk (Bostik, 888/603-8558, www.bostik-us.com).
Avoid the temptation to use a reactive polyurethane glue like Gorilla Glue (800/966-3458, www.gorillaglue.com). While it's true that this type of adhesive can provide a sturdy glue joint in the presence of surface contaminants, its curing process causes it to foam. Because you won't be able to apply adequate clamping pressure until the glue cures (nails alone probably wouldn't suffice), the joints would end up with unattractive, excessively foamy glue lines.
