Graffiti
Graffiti is unsightly and often offensive. It degrades the value of property and contributes to a moral malaise.What, therefore, can be done about it?The answer is - quite a lot and certainly a lot more than is done at present.
As with most problems, prevention is better than cure. Of course, short of employing 24 hour security guards, we can't stop graffitists applying graffiti. However, we can turn to some new, and very clever, surface coatings which will protect the substrate and make removal of the graffiti much easier. The use of a protective coating is particularly attractive because surfaces such as concrete, sandstone, marble, brick and other porous materials can be extremely difficult to clean. Sand blasting is often not practical and painted substrates may themselves be damaged in the process of removing the graffiti. Removing graffiti from an untreated porous surface is especially difficult as the solvent will tend to wash the pigments into the substrate and not away from it.
Nonetheless, prompt removal of graffiti is essential as it discourages the graffitist whose 'work' is no longer on display.
Another reason for the prompt removal of graffiti is that paints are more easily dissolved in solvents within the first 72 hours of application.The longer they are left to bake in the sun, the less soluble they will become and the harder it will be to remove them.
Of course one might consider simply painting over the graffiti with a fresh coat of paint. In many cases this might be quicker and cheaper than removal and is certainly worth considering.
However, if the graffiti is to be removed then such removal can be greatly assisted if the substrate has been protected by an anti-graffiti coating. And, incidentally, such a coating can also provide protection from the normal wear and tear of the elements.
Anti-graffiti protective coatings come in a number of different forms. Choosing the right one will depend on the substrate and the likely form of the graffiti.The paint manufacturer will be able to advise on the most appropriate protective coating to use.
One effective form of protective coating is the two pack polyurethane. This coating will provide a tough clear finish with minimum detraction from the colour and texture of the substrate.The characteristics of a two pack polyurethane are:
- easily cleaned hard tile-like surface
- abrasion resistant
- very good chemical resistance
- non-yellowing.
It is the solvent resistant features of the two packs that enable these coatings to protect surfaces through several cycles of graffiti application and removal. By obstructing the passage of liquids and solids into building material substrates they make the substrates less absorptive.Graffiti can then be removed from the coated surface with appropriate solvents.Most polyurethanes are also resistant to discolouration or degradation due to ultraviolet exposure and weathering. Some are also hydrophilic which permits the masonry to "breathe."
Another way of dealing with graffiti is to use a 'sacrificial' system such as an acrylic lacquer. These fast drying coatings provide a clear gloss protective finish suitable for internal or external application over aluminium, copper and other non-ferrous metals.They are generally not recommended for previously painted surfaces.Masonry and sand stone surfaces can be sealed by applying two or more coats (depending on porosity).Application is by short nap roller or conventional spraying equipment. Small areas may be brushed.Two coats are recommended. When cleaned with an appropriate solvent the entire system washes off taking the graffiti with it.
Removing the Graffit
Graffiti caused by aerosol paints is the most difficult to remove.But other materials such as felt tip markers, shoe polish, crayons and ordinary paint may be encountered.Different types of solvents may therefore be required for their removal. Again the paint manufacturer will be able to provide advice as to the right solvent to use on a particular substrate.It would also help if at the same time the graffiti material could be identified.
Marker Pens and Other Graffiti Materials
Graffiti produced by some marker pens, crayon and lipstick, can be removed by detergent and water. A soft paint brush should be used to gently rub in sudsy water. A water rinse should complete the job. A second application may be necessary in some cases.
Most marker pen graffiti, however, is solvent based, and will not be removed by the above procedure. These marks are removed by the techniques described earlier.
Remember that all removers work best at higher temperatures. For this reason, graffiti removal should be attempted when substrates are warm. This is possible even in winter if the sun has warmed the substrate while air temperature is low. A hot surface, however, will tend to dry out the solvent. In this case, continued application should be made to keep the surface wet with solvent.
A great number of graffiti removers, or solvents, are on the market. Many are specifically designed by paint manufacturers to work with the protective coatings they also supply.One NSW company is now marketing a range of non-toxic, bio-degradable, non-flammable water solvable graffiti removers that can be brushed or sprayed on and even has a pleasant citrus smell!
Graffiti is a problem but not an intractable one.The way to deal with it is to use an anti-graffiti protective coating whenever possible and to remove the graffiti within three days not only because this makes removal easier but also because it is a proven way of discouraging further graffiti.
Health & Safety Precautions
The need to take proper health and safety precautions particularly when applying two pack polyurethanes and using chemicals solvents for the removal of graffiti, is essential. The manufacturer's instructions for these products must be read and followed to the letter.In some cases special equipment and personal protective clothing may be required. Work should not proceed unless all these precautions have been observed.In cases involving the use of chemical solvents in the removal of graffiti it may be appropriate to engage a firm which specialises in such work.
by Richard Phillips
Executive Director of the
World Paint & Coatings Industry Association |