Many projects require some kind of adhesive or sealant, and it is important to use the one most appropriate for each task. Learn how to choose the right adhesive for your project.
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The most widely used adhesives are described here. Other types are designed for use with particular products, such as vinyl. Mirror adhesives, for example, do not affect mirror backings that might be stained by all-purpose adhesive.
Wood glue: Yellow in color, this is designed specifically for bonding sections of wood. Working time is about 15 minutes. It has a shelf life of about one year.
Contact adhesive (contact cement): A very strong solvent-based adhesive, this can be used to bond a large range of materials including wood, metal, many plastics and decorative laminates. It is not suitable for use with some materials, such as polystyrene and bitumen, or as a mirror adhesive, so check the manufacturer's instructions before using it.
Construction adhesive: Used to bond surfaces that cannot easily be joined with screws or nails, or combined with mechanical fasteners to form very strong bonds. Available in tubes and sealant-like cartridges. Most (especially water-based and solvent-free types) need at least one of the surfaces being bonded to be porous.
Resin: Made up of two elements that mix once they are dispensed from the cartridge, resin creates very strong bonds. Where a secure anchoring point for a wall fixture is required (on shelves, for instance), resin is injected into the hole before the fixture is inserted.
Expanding foam: Supplied in an aerosol can, this foam is used to fill large gaps, bonding to their edges.
Aim the nozzle into the hole in the wall, and discharge the resin adhesive into the hole (Image 1).
Immediately press a heavy-duty fastener into the resin, and allow the adhesive to set before hanging any heavy item from the fastener (Image 2).
Polyurethane-based expanding foam can fill large gaps or holes, and bonds the surfaces in the process. Some varieties have greater heat resistance than others. This is an important feature in some situations, such as when installing a flue. In this example, foam is being used to fill the gap around a drainage pipe.
Point the nozzle into the hole in the wall, and discharge the foam into the hole (Image 1).
After about five or 10 minutes, the foam will begin to bubble and expand. It will then set (Image 2).
Once it has set, the foam can be cut away using a saw to neaten the overall finish. Finer trimming can be carried out with a utility knife (Image 3).
Holes in the trimmed area can then be filled with an all-purpose filler compound, sanded, and decorated as required (Image 4).
Excerpted from Do It Yourself Home Improvement
© Dorling Kindersley Limited 2009