You can use the following polyurethane adhesive tips for woodworking projects to insure strong and quick bonding of wood, while also taking advantage of its wood-filing properties. Although slightly more expensive than traditional wood working glues, polyurethane adhesive is also waterproof, will strongly bond two unlike substances together, and will remain effective (shelf life) up to a whole year.
End Grain to End Grain
Polyurethane adhesive works well for gluing pieces of wood with the grains running parallel to each other, such as gluing boards together for table tops or to make wide boards. Its real strength has been proven while gluing pieces of wood together where an end joint will butt against the running grain of another piece of wood, or gluing end joints together. This is a joint that can fail under heavy pressure, but not as easily when polyurethane adhesive is used.
The expanding nature of polyurethane glues makes for better end to end joints because these joints tend to draw the glue into the fibers causing a solid, waterproof and self-filling joint.
Oftentimes, when building furniture or other woodworking projects unwanted spacing occurs between joints. Because of the expanding nature of polyurethane as it dries, it naturally will fill in small gaps between joints without the using common wood fillers or wood putty. This attribute of polyurethane adhesive is especially useful for repairing older pieces of furniture where joints have been worn down and gaps have appeared between joinery.
Sand and Stain
Thanks to polyurethane adhesive’s gap filling nature, joints can be sanded smoothly providing excellent joinery. Additionally, this adhesive will readily accept stains and allow complete blending of joinery. This is not to say that it is foolproof and will compensate for ill fitting joints or sloppy work. However, it will go a long way towards covering up and compensating for minor joinery flaws and obviate the need for fillers that actually call attention to small gaps and spaces between joints.
Although the traditional adhesive for many waterproof applications has been epoxies, many manufacturers of polyurethane adhesives are touting their products for boatbuilding and waterproof usage. After much testing, even epoxy manufactures cannot default polyurethane adhesives as being completely waterproof. Another plus is that it is a single application adhesive, unlike the traditional two-part epoxies traditionally used for boatbuilding and waterproofing applications.
Sticks to Anything
Another big plus of polyurethane adhesive is that it sticks to a large variety of similar and dissimilar materials. Where traditional adhesives have had separate niches in the market place, polyurethane is being used as a more universal adhesive with a broad spectrum of applications. There is some controversy between some of the more traditional “woodworking” glues and the polyurethane newcomers, and there have been different testing of both products, each with varying results. As with most traditions, there are some who will resist the newer technology of polyurethane adhesives, but what is indisputable is that it performs at least as well as what is currently on the market, if not better in some instances.