|
|
|
Protection & Removal - Protection
Removal of graffiti can be difficult and unpleasant. This can be especially so when it requires the use of the more powerful chemical solvents. Often, no matter how strong the solvent some surfaces will retain a ‘ghost’ of the offending graffiti where the porosity of the material has allowed the paint or ink to penetrate. A surface can be ‘protected’ by making it much easier to remove graffiti from it without visible damage. Sealing the surface with a protective coating does this.
Protective Coatings
The use of protective coatings can:
- Make removal easier and more effective
- Reduce the harmful physical effects on a surface of graffiti materials
- Reduce the harmful physical effects of the removal process itself
There are many variables and points for caution in the match of surface material, coating and removal products. It may not be wise to use permanent coatings on sandstone especially ‘heritage’ sandstone, certain solvents may still be able to easily remove some ‘permanent’ coatings and some solvents may cause more damage than the graffiti.
However, it is possible to make general recommendations about what types of protective coatings and removers may be best in dealing with graffiti. Broadly, there are two types of coating: sacrificial and non-sacrificial (permanent).
Sacrificial Coatings
The sacrificial coating is one that is removed along with the graffiti when it is cleaned from a surface.
Advantages:
- Often water based and not as toxic as non-sacrificial coatings, often single pack, often easy to apply.
Should be cheaper, purely on a materials basis, than non-sacrificial coatings.
Disadvantages:
- Require re-application after nearly every graffiti removal attempt.
May suffer in very hot climates from slight softening and dirt pick up.
Non-sacrificial (or ‘permanent’) Coatings
Non-sacrificial coatings are intended to remain in place for a considerable period of time and through repeated removal of graffiti. (It is inevitable that with a number of removal treatments, especially if accompanied by abrasion, the coating will break down and be removed.)
Advantages:
- Relatively non-toxic removers may be used.
The coating will last for many removal attempts.
Disadvantages:
- Two pack system, can require careful application, often more expensive.
Individual components of two pack system may be more toxic than the cured coating.
|