Special leather glues are available, but that doesn’t mean they’re suitable for all applications. In fact, the leather market is vast: leather goods, saddlery, shoemaking, furniture, etc. Whether it’s a question of repairing, designing or decorating leather objects, the techniques and materials used can vary from one project to another. If knowing the main categories of glue on the market can already give you a number of pointers, we’re going to tell you which type of glue to choose for your specific project.
Leather is a delicate, flexible material. When it comes to leather bonding, it’s important to bear in mind that this involves a second substrate, namely the leather bonding partner. It can be a flexible material like fabric, or a hard one like wood or metal.
For example, most leatherwork involves gluing pieces of leather together. This is known as positional gluing, and involves joining leather pieces together with adhesive to hold them in place during sewing. Also, in the shoe or furniture industry, it is often necessary to glue one piece of leather to another or to a fabric. In the above-mentioned cases, the aim is to glue leather to a flexible substrate, whereas in other trades, the aim is to glue leather to hard substrates such as metal, wood, porcelain or plastic.
Bonding leather to a hard or flexible material will not require the same type of glue. Indeed, gluing flexible materials together requires the use of an elastic glue so as not to stiffen the object, whereas a super-glue can be used to glue leather to hard surfaces.
Contact adhesives with a physical setting are recommended for bonding leather with other flexible materials. Solvent-based adhesives and water-based adhesives (also known as dispersion adhesives) have the advantage of not penetrating the leather surface, and of remaining flexible after reaction (solvent evaporation). Neoprene glue is the most commonly used type of glue for bonding leather with other malleable surfaces, as it offers strong adhesion and good resistance to humidity. A thin layer is all it takes to bond flexible substrates together. However, water-based spray glue is just as effective as solvent-based glue for gluing leather to soft materials.
When it comes to adhering leather to a solid surface, there are several glues to choose from. Vinyl glues are best for bonding to wood, while cyanoacrylate glues are ideal for bonding leather to a metal surface.
The latter are instant glues, commonly known as superglue, which belong to the reactive glue category. Unlike contact adhesives, which harden via solvent evaporation, glue is formed via a chemical process. As cyanoacrylate adhesives are mainly used for bonding small surfaces, it is common to use neoprene adhesives for bonding large surfaces.
Double-sided adhesive tape is also ideal for bonding large leather surfaces to hard materials.
Leather is a delicate and complex material which can react in different ways to adhesive. To find out whether your professional glue is suitable for the type of leather you use for your work, it’s important to test the adhesive on a sample to check that the quality of the leather doesn’t deteriorate. Another technique for testing adhesive is to do a peel test by hand. If the fracture surface is adhesive, this reflects poor bonding, as it means that the adhesive has remained on only one of the two substrates.
If you’d like to benefit from personalized advice from professionals, don’t hesitate to call on the experts in the ‘Lineo network.
