Renovation Around the Home - Choosing and Applying Adhesives

The wide range of adhesives available can make choosing the right one for the job a daunting experience. Here we clarify what is available in the shops, how to select the right product and how to apply the adhesives to ensure perfect results. There are adhesives available today for sticking almost every type of material to any type of surface, but it can be confusing trying to select the right one for the job.

The adhesive you choose for any job will usually depend on the items to be stuck together. There is a 'right' adhesive for most jobs. That is, one that has been especially formulated for the type of materials it will be app­lied to and therefore gives maximum performance. By following manufacturers' in­structions carefully and choosing the right type of adhesive, it is pos­sible to ensure a perfect result with every job.

General purpose glues

When convenience and ease of use are more important than strength, satisfactory results can often be achieved by using a general purpose or household adhesive.

These are clear solvent-based adhesives which will stick paper and cardboard, wood, leather, even some plastics, and are used straight from the tube. Check the instructions care­fully; some recommend applying the adhesive to both surfaces, others to just one. Whichever method you use, you need to hold or clamp the repair and the adhesive takes some time after assembly to gain full strength. The joint is generally not water or heat-resistant.

Remember that general-purpose adhesives are inflammable and give off unpleasant vapours, so should be used in a well ventilated area. For these reasons they should be kept well out of the reach of children. Most adhesives can be cleaned from your fingers (or anywhere else it gets by mistake) using acetone or nail varnish remover.

 

Sticking paper and card

Numerous adhesives are specifically for use on paper or card. Water-based liquid pastes and gums sold in bottles or jars are usually supplied with a spreader or brush. They are simple to apply and safe for children to use, and any ex­cess glue can easily be removed using a slightly damp cloth. It does have one drawback in that the paper has a tendency to wrinkle as the water dries out, Stick glue is a semi-solid adhesive that comes in a small cartridge. It is very easy to apply and is suitable for children to use. Remember to replace the top after use or the stick will dry out.

Rubber solution adhesives should be spread on both surfaces; leave until the adhesive is touch-dry and then press the surfaces together. Any surplus dried glue is easily peeled off with your fingers. Aerosol spray adhesives are easily applied with a sweeping motion. Coat one surface, allow it to dry and then press into place.

Both rubber solution and aerosol adhesives are ideal for covering large areas and give a smoother, more pro­fessional finish. However they must be used with care as they give off in­flammable vapours, and are un­suitable for children to use. Reusable adhesives, such as Blu-tack are similar in appearance to putty. They are easy to peel off and reuse, but they can stain walls and wallpaper if they are left in position for too long.

Adhesives for wood

PVA woodworking adhesive, also known as 'white glue' is the most popular type for general wood­work. It's a milky liquid which will bond softwood, hardwood and all man-made boards, and is colorless when dry.

The joint must be clamped in posi­tion for at least two hours until the adhesive hardens. Make sure spills are wiped away with a damp cloth before the adhesive sets.

This type of glue is moderately water-resistant, but prolonged ex­posure to dampness will result in the bond coming loose. A heat-resistant and water­proof bond can be achieved by using a brand of adhesive specifically labelled for this task.

There are several types available. Some come as powders which you mix with water, others are packaged as separate powder and hardener to be mixed in specified quantities.

Once mixed, these adhesives have a limited pot life — in other words, they remain usable for only a short time. This is usually between two and four hours, but check with the manufacturer's instructions.

As with PVA adhesives, for the best results, the joints will need to be clamped until the glue is quite dry.

Adhesives for laminates

Contact adhesives are the most suitable for sticking lamin­ates, and flexible sheet materials such as foam or leather. The adhesive is spread on both surfaces and is allowed to become touch-dry before the two are pressed together. This needs to be done with extreme care because the resulting bond is instant. Thus the pieces cannot be moved again unless you use a brand which offers a de­gree of slip (often called a thixotropic adhesive. It is quite heat proof and water-resistant.)

Most contact adhesives are sol­vent-based, and the fumes are both inflammable and noxious to inhale, so work in a well ventilated area and do not use naked lights. Clean any up spills using the manufacturer's special solvent, or try acetone (nail varnish remover). Water-based types are also available, and these are much safer and more pleasant to use; spills can be removed with a damp cloth.

Adhesives for plastics

Many plastics are very difficult to stick with adhesives. Two which cannot be stuck satisfactorily by any means are nylon and polythene; they must be fused by heat. Special vinyl repair adhesive will mend flexible PVC — used for seat covers, sunbeds and beach balls. Polystyrene cement will mend rigid polystyrene — used for some kitchen and bathroom accessories. However it is not suitable for ex­panding polystyrene ceiling tiles. For other plastics, experiment with epoxy resin adhesives, two-part acrylics or cyano-acrylates.

Glass, china and metal

There are three types of adhesives available for these materials. Epoxy resin adhesives are two-part products. Equal quantities of resin and hardener are mixed together, and applied — usually to both surfaces. Quick-setting types set in a few minutes, others take about half an hour for the full bond strength to develop. Once set, the bond is heatproof and waterproof. This type of adhesive can also be used successfully to fill gaps. However, it does leave a notice­able glue line, which may darken with time. Clean up any spills with white spirit, and trim away any dried adhesive with a well sharpened handyman's knife.

Cyanoacrylate adhesives, also known as superglues, are thin runny liquids which are applied to just one surface. The resulting glue line is very thin, so they are ideal for re­pairing crockery and glass. One drawback with this adhesive is that it has no gap-filling properties so the parts must be a good fit.

With most brands, the joint is not waterproof, but some are specially formulated for repairing items that will have to be washed or hold liquids, such as mugs and cups. Avoid skin contact when using this type of adhesive. If you do get your fingers (or anything else) stuck together, immerse them in hot soapy water and peel the stuck areas apart. Alternatively you can use the manufacturer's release agent if one is supplied with the adhesive. Two-part acrylics are not mixed directly. You apply adhesive to one surface and hardener to the other, then bring the two together.

This sticks immediately, setting to full strength in a few hours. The adhesive has good heat resistance and is quite waterproof, but doesn't fill gaps very well. Wipe up spills with a dry cloth, trim away any dried adhesive with a sharp knife.

 

Adhesives for fabrics

The best adhesive for sticking fab­rics and carpets is a latex type - a white liquid which works like a con­tact adhesive. Brush adhesive on to the two surfaces, allow them to be­come touch-dry and then press together. Wipe up any spills that may occur with a damp cloth.

 

Adhesives for glue guns

Glue guns are electrically-heated tools that take sticks of adhesive. These sticks are melted down and the adhesive is then applied via a nozzle. Initially they were intended only for woodwork, but a variety of sticks are now available which can be used for general purposes.

 

Speciality adhesives

Your local DIY store will also sell all sorts of one-job adhesives, clearly labelled as to their purpose. These include wallpaper paste, ceramic tile adhesive, coving adhesive, panel adhesive and so on. You just need to pick out the one appropriate for the job in hand.