Outdoor artworks are very prone to “wear and tear” caused by ageing especially due to environmental hazards and conditions. It can often be challenging, costly and impractical to clean these precious works of arts with traditional methods. Thanks to lasers though there is a relatively new method of cleaning stonework, statues and monuments, which is what we focus on in this application insight.
What type of stonework can fiber lasers clean?
Many types of stonework can be cleaned. In this guide we are focusing on the cleaning of items such as brickwork, masonry, monoliths, monuments, sculptures, stonework, statues and tombstones. Any of these (and more besides) can be safely cleaned.
Why is there a need for laser cleaning?
Stonework over the passage of time will become contaminated, unsightly and worst-case scenario may start to crumble and disintegrate due to erosion. A periodic clean is needed to protect valuable stonework as it’s much cheaper to clean than to repair/replace.
Outdoor stonework and artworks are vulnerable to many pollutants and contaminants, these include (but are not limited to) air pollution (the removal of nitrates and sulphates e.g. acid rain, aerosols, etc.), algae, bird droppings, fungi, lichen, graffiti removal, moss and storm damage. Perhaps the most major outdoor contaminator is traffic grime, which typically produces a black film layer of soot, dirt and grime, which can be hard to remove.
A fiber laser will be able to clean damage caused by any of the above pollutants and contaminants.
Full restoration through acid erosion won’t be possible via the ablation process but could be possible via additive manufacturing and/or the use of a skilled Stonemason.
Why is the ablation process ideal for restoring stonework?
The cleaning of stonework typically is an ablation technique, which is fairly easy to describe. The area of stone (or similar material) with the surface contamination is focused with the laser beam and the precise amount of debris is ablated from the surface. The results of this process can be astonishing and make a fundamental difference to the appearance of the stonework.
It’s important for the fiber operative to target the surface layer only, so as not to disturb the underlying layers (i.e. the actual stone). As the laser beam takes effect, the surface layer contaminants are ablated off. The process is performed with absolute precision to deliver a quality finish, which causes no damage to the surrounding stone.
What are the Advantages of the restoration process?
Listed below are some of the main advantages of restoring stonework with lasers from SPI:
- Accuracy, precision and control – laser processes are renowned for their amazing precision and control. This is especially important in stonework restoration as ageing stonework needs to be restored with sensitivity. This also enables specific areas to be targeted, which may have been subject to damage, whereas other areas many not requirement treatment
- Chemical free – irrespective of the chemical used in traditional processes there are risks to the user and the item being cleaned. Chemical cleaning:
- releases noxious fumes (which can be environmentally damaging)
- leaves waste residues
- can structurally alter the item internally
- whilst also being potentially corrosive (especially when scrubbing is used) and
- always has the risk of permanent damage
- Non-contact process – although perceived by many as sturdy, some stonework can be subject to crumbling, especially with age. Lasers can restore all types of stonework without the need for contact from any type of machine or the laser operative
- Speed – although quality of restoration is perhaps the over-riding objective, another benefit is that laser ablation/cleaning of stonework is also very fast, infact much quicker than traditional processes