Prepared by the FEVI Technical Department | Published 5 September 2026
Abrasive blasting in restoration requires a very different approach from abrasive operations carried out on industrial surfaces or new materials. When working on stone, marble, wood, metals, brick or historic artefacts, the objective is not to achieve maximum removal capacity, but to selectively remove deposits, old coatings, oxidation or surface alterations while preserving as much of the original material as possible. A blasting machine for restoration must therefore provide accurate control of the treatment through adjustment of pressure, abrasive quantity, particle size, nozzle diameter, distance and exposure time. Microblasting, controlled low-pressure blasting, abrasive recovery blasting and other technologies can be used according to the artefact and the required result. To identify the most suitable machine for a specific application, also read the guide How to choose a blasting machine for restoration or view the FEVI solutions for restoration.
Blasting in restoration does not simply mean removing material
In conservation restoration, the surface may contain information that forms part of the history of the artefact.
Patinas, traces of original workmanship, engravings, pigments, finishes, signs of use and changes that have occurred over time should not automatically be considered materials to be removed.
Before starting treatment, it is therefore necessary to distinguish between:
A technically effective treatment can be excessively invasive if original material is removed together with the deposit.
The principle of minimum intensity
One of the most useful approaches when treating delicate surfaces is to start with the least aggressive configuration capable of producing an appreciable result.
Intensity can then be adjusted progressively by changing:
- air pressure;
- abrasive quantity;
- particle size;
- type of abrasive;
- nozzle diameter;
- distance from the surface;
- abrasive-stream angle;
- movement speed;
- number of passes.
Removal capacity should therefore be increased gradually and only when necessary.
On a historic artefact, maximum working speed does not necessarily represent the best result.
Why a preliminary test should always be carried out
Before treating the entire surface, it is advisable to carry out a test on a limited and representative area.
The sample test makes it possible to assess:
- the response of the substrate;
- effectiveness in removing the deposit;
- any change in the finish;
- colour variations;
- loss of material;
- abrasive behaviour;
- required pressure;
- working distance;
- uniformity of the result.
Where the artefact is particularly delicate or historically significant, the test should be carried out in accordance with the instructions of the professional responsible for the conservation work.
The configuration established during the sample test should then be maintained and documented throughout the subsequent treatment.
Microblasting in restoration
Microblasting generally uses fine abrasives, small-diameter nozzles and an abrasive stream concentrated on a limited area.
It is particularly useful when working on:
The main advantage of microblasting is the ability to control the treatment area precisely.
This does not mean, however, that the process is automatically harmless. Even a micro-abrasive stream can alter a surface if abrasives that are too aggressive, excessive pressure or excessively long exposure times are used.
The delicacy of the process therefore depends on the complete treatment configuration, not simply on nozzle size.
For further information, view the FEVI microblasting machines.
Low-pressure blasting in restoration
For larger surfaces, a portable blasting machine capable of operating at low pressure with controlled abrasive metering can be used.
Low-pressure blasting can be considered where a microblasting machine would be too slow, while good process control is still required.
It can be assessed, for example, on:
- architectural elements;
- stone;
- marble;
- brick;
- beams;
- wood;
- metal artefacts;
- historic building surfaces;
- structures requiring restoration.
In this case too, “low pressure” does not automatically mean a delicate treatment. A hard abrasive, coarse particle size or prolonged exposure can alter the substrate even at relatively low pressures.
SABIX 8 in restoration
SABIX 8 is an 8-litre FEVI professional portable blasting machine that can also be used for controlled operations in the restoration sector.
The machine allows adjustment of the main parameters that determine blasting intensity and can be configured according to the material, abrasive and required result.
Compared with a microblasting machine, it provides greater working capacity on small and medium-sized surfaces while retaining compact dimensions and ease of handling.
It can be considered for work on:
- stone;
- marble;
- terracotta;
- brick;
- wood;
- iron and other metals;
- architectural elements;
- beams;
- artefacts;
- structures requiring restoration.
SABIX 8 is not, however, a universal solution for every restoration project: for very small details or particularly delicate artefacts, a microblasting machine may be more appropriate, while other applications may require abrasive recovery or different technologies.
Treatment of materials in restoration
Restoration of natural stone
Natural stone includes materials with very different characteristics. Marble, granite, sandstone, limestone, travertine, slate and other stones can vary considerably in hardness, porosity, cohesion, finish, condition, presence of fractures, surface erosion and previous treatments.
A configuration that is effective on compact granite may be excessively aggressive on soft or deteriorated stone. Before treatment, the stability of the material should therefore be assessed and precisely what needs to be removed should be established.
Marble blasting in restoration
Marble may feature deposits, blackening, residues from previous treatments, pigments, waxes, encrustations or alterations caused by environmental exposure.
The treatment must take the original finish into account. Polished, honed, bush-hammered, sculpted or engraved surfaces cannot automatically be treated using the same parameters.
An unsuitable abrasive or treatment intensity can alter reflectivity, roughness and the original appearance of the material. In the stone sector, abrasive blasting is also used for engraving and decorative work, but these applications should be distinguished from conservation treatments.
Terracotta and historic brick
Terracotta and brick can be particularly sensitive to abrasive treatment where the surface layer has deteriorated. Porosity, friability, possible efflorescence, previous paint, wax or protective treatments, loss of the surface layer and the presence of poorly cohesive areas must all be assessed.
Excessive treatment can increase roughness and porosity or expose less resistant material beneath the surface. For this reason, the preliminary test is particularly important.
Wood blasting in restoration
In wood restoration, controlled abrasive blasting can be used on beams, shutters, window frames, doors, furniture, components, decorative elements and old finishes.
Softwoods and hardwoods respond very differently to abrasive action. Excessively aggressive treatment can remove softer fibres more quickly, emphasising the grain or producing an unwanted carved effect. On veneers, decorations, gilding, polychrome surfaces and surfaces of particular value, treatment must be assessed with extreme caution.
The objective must be defined before treatment: removing paint, reducing a deposit or deliberately producing a particular surface effect are different operations.
Metals and historic components
Microblasting and controlled abrasive blasting can also be used on metal components made from iron, steel, bronze, brass, copper, aluminium and alloys. On iron and steel, it may be necessary to remove rust or old coatings. On bronze, copper and other historic materials, however, a careful distinction must be made between corrosion that needs to be removed and patina that should be preserved.
A patina may in fact have historic, aesthetic or protective value and should not automatically be removed.
Statues, bas-reliefs and sculpted surfaces
Complex geometries are among the applications where control of the abrasive stream is most important. Bas-reliefs, statues, frames and decorations may feature delicate edges, engravings, undercuts, concave surfaces, very small details and different levels of preservation within the same artefact.
In these cases, a micro-abrasive stream makes it possible to concentrate treatment, while a more productive system must be used with greater caution. The objective is to act on the deposit without rounding edges, erasing details or altering the original geometry.
Types of treatment on historic artefacts
Removal of blackening and surface deposits
Consolidated dust, soot, atmospheric particulate matter and other deposits can progressively alter the appearance of a surface. Before treatment, it is important to determine the nature of the deposit, adhesion, thickness, substrate porosity, presence of surface transformations and any interaction between the contaminant and the material.
The objective is not always to restore the surface to its original colour. In some conservation treatments, controlled reduction of the deposit may be more appropriate than complete removal, which could also affect the underlying material.
Old paint and coatings
The difficulty involved in removing old paint depends on its composition, number of layers, adhesion, elasticity, penetration into pores and the condition of the substrate. Simply increasing pressure until the coating is removed may damage the surface before the desired result is achieved. The complete configuration should therefore be considered: abrasive + particle size + pressure + nozzle + distance + exposure time.
Graffiti removal in restoration
Removing graffiti from stone, marble, brick and historic surfaces requires particular care. Paint and pigments can penetrate into the porosity of the material. Persisting mechanically in an attempt to remove every trace completely can result in removal of the artefact's surface layer. Treatment should therefore be preceded by progressive tests and an assessment of the relationship between the aesthetic benefit of removal and the possible alteration of the substrate.
Complementary technologies in restoration
Abrasive recovery blasting in restoration
An abrasive recovery blasting machine can be useful where a surface needs to be treated while limiting the dispersion of abrasive and dust. The machine head is maintained in contact with the substrate and extracts the material during treatment.
This configuration can be considered for relatively regular surfaces, architectural elements, localised work, indoor environments and areas where dispersion must be contained.
Surface geometry nevertheless represents an important limitation. Reliefs, deep engravings, edges and undercuts can prevent the head from maintaining proper contact. In these cases, controlled open blasting or a microblasting machine may be more appropriate. Learn more about the FEVI abrasive recovery blasting machines.
Blasting with pre-dampened abrasive
In some applications, water can be added to the process to help reduce airborne particles. Pre-dampening can be useful on worksites or on surfaces that are compatible with the use of water.
Before use, however, the sensitivity of the material to water, the presence of salts, porosity, environmental conditions and any subsequent treatments must be assessed. In restoration, wet blasting therefore cannot automatically be considered better than dry treatment: compatibility depends on the artefact.
Dry ice treatment in restoration
Dry ice cleaning uses solid CO₂ pellets conveyed by compressed air. The dry ice sublimates after impact and leaves no secondary residue from the treatment medium.
This technology can be considered where the aim is to avoid mineral abrasives, water, detergents or residues from the treatment medium. It can be useful for some organic residues, soot, waxes, grease and contamination. It does not, however, universally replace microblasting. Mineral encrustations, resistant oxides or treatments requiring genuine abrasive action may require different technologies. The compatibility of the material with thermal variation should also be verified by means of a preliminary test.
Learn more: FEVI dry ice blasting machines.
Process parameters and control in restoration
Which abrasive should be used in restoration?
Abrasive selection is one of the most delicate aspects of the process. Hardness, particle shape, particle size, friability, density, purity and behaviour on the material must all be considered. There is no universally “gentle” abrasive. A relatively low-aggression material can still alter a friable surface if it is used too close to the substrate, with excessive dosage or for too long. Selection must always be related to both the material to be preserved and the deposit to be removed.
Particle size and treatment control
Fine particle sizes generally allow greater control over limited areas and are often used in microblasting. The result also depends, however, on particle geometry, pressure, nozzle diameter, airflow and abrasive quantity. Simply reducing particle size does not automatically guarantee a less invasive treatment: all parameters must be considered together.
Operating pressure
A blasting machine for restoration must allow adjustment that is consistent with the sensitivity of the substrate. Pressure should initially be set conservatively and increased only when the test shows that the treatment does not produce unwanted alterations. It is not appropriate to define a universal pressure for stone, marble, wood or metal: apparently identical materials can have very different states of preservation.
Nozzle, distance and angle
Three frequently underestimated factors are:
- Nozzle diameter: affects the abrasive-stream area, airflow and quantity of abrasive used.
- Distance: reducing the distance from the surface generally increases the concentration of the abrasive action.
- Angle: the angle of incidence changes abrasive behaviour and can be used to modulate the effect on the surface.
An experienced operator uses these parameters together with pressure to progressively control the treatment.
Compressed air and process quality
Compressed-air stability is particularly important when small nozzles and fine abrasives are used. Moisture or condensate can cause abrasive agglomeration, irregular flow, blockages and variations in the amount of material projected. The compressor must also provide airflow compatible with the nozzle being used. Unstable pressure makes it more difficult to reproduce across the entire artefact the parameters established during the preliminary test.
Micro Blaster for precision applications
FEVI Micro Blaster is a microblasting machine designed for localised operations and applications where the abrasive stream needs to be concentrated on very small areas.
It can be considered in restoration for:
- engravings;
- details;
- small artefacts;
- sculpted elements;
- marble;
- stone;
- metals;
- ceramics;
- laboratory applications.
Productivity on large surfaces is necessarily lower than with a higher-capacity portable blasting machine, but the main advantage is the precision of the treated area.
Micro Blaster or SABIX 8?
The two machines meet different requirements.
| Application | Technology to consider |
|---|---|
| Details and engravings | Micro Blaster |
| Small artefacts | Micro Blaster |
| Extremely localised treatment | Micro Blaster |
| Small or medium-sized surface | SABIX 8 |
| Worksite applications | SABIX 8 |
| Beams and wooden components | SABIX 8 |
| Controlled treatment of architectural surfaces | SABIX 8 |
| Extremely delicate geometries | Preliminary assessment + microblasting |
The choice should not be based solely on machine size or price, but on the required level of precision and productivity. For a broader comparison of FEVI technologies for restoration, read How to choose the right solution for restoration.
What to avoid when using abrasive blasting in restoration
- trying to return every surface to the appearance of new material;
- immediately increasing pressure when the deposit resists removal;
- using an abrasive without first verifying its compatibility;
- remaining on the same area for too long;
- working excessively close to the substrate;
- ignoring differences in preservation within the same artefact;
- removing patinas that should be preserved;
- using the same configuration on different materials;
- treating the entire surface without carrying out a preliminary test;
- selecting the machine solely according to productivity.
In restoration, control and selectivity are generally more important than removal speed.
Blasting in restoration and operator safety
The process can generate dust from both the abrasive and the material being removed. The composition of the residues should be assessed before treatment. Old paint, contamination, corrosion products and treatments applied in the past may generate materials that require specific management procedures.
Protective equipment, containment, extraction and filtration must therefore be appropriate for the specific application and the associated risk assessment.
Maintenance of blasting machines used in restoration
When operating with low abrasive quantities and precise settings, component wear can also change system behaviour. The following should be checked periodically:
- nozzles;
- hoses;
- valves;
- metering systems;
- fittings;
- condensate separators;
- filters;
- blasting guns;
- components through which abrasive passes.
A progressively worn nozzle changes in diameter and can therefore alter both airflow and the characteristics of the abrasive stream.
Frequently asked questions about abrasive blasting in restoration
Can abrasive blasting be used in conservation restoration?
It can be used where the material, state of preservation and objective of the treatment are compatible with a controlled abrasive process. Preliminary tests should be carried out and configurations appropriate to the sensitivity of the substrate must be used.
What is the difference between microblasting and conventional abrasive blasting?
Microblasting generally uses a more concentrated abrasive stream, small nozzles and fine abrasives, prioritising control over limited areas. A conventional blasting machine can provide greater productivity on larger surfaces.
Which blasting machine should be used for a bas-relief?
For details, engravings and complex geometries, a microblasting machine may be suitable because it allows treatment to be concentrated on a small area. The configuration should nevertheless be verified by means of a test.
Can SABIX 8 be used in restoration?
Yes. It can be considered for controlled operations on small and medium-sized surfaces, architectural elements, stone, marble, terracotta, wood and metals. For very small details, a microblasting machine may be more appropriate.
What pressure should be used on a historic surface?
There is no universal value. Pressure should be identified through progressive testing, taking into account the material, state of preservation, abrasive, nozzle and required result.
Which abrasive should be used?
It depends on the substrate and the material to be removed. Abrasive hardness, particle size and shape must be assessed together with the sensitivity of the surface.
Does microblasting never damage the material?
No. It remains a mechanical abrasive process. An incorrect configuration can alter even a resistant surface.
Can an abrasive recovery blasting machine be used in restoration?
Yes, particularly on relatively regular surfaces and where containing abrasive and dust is important. On reliefs, deep engravings and irregular geometries, the recovery head may be less suitable.
Can dry ice replace microblasting?
Not always. It is a different technology, particularly useful for certain types of contamination and where the use of water and mineral abrasives needs to be avoided. It does not, however, provide the same abrasive action as microblasting.
Blasting and restoration: control comes before productivity
A blasting machine for restoration should allow the operator to adapt the treatment to the artefact rather than forcing the artefact to adapt to the characteristics of the machine.
The correct configuration starts from an analysis of:
Microblasting machines such as Micro Blaster and adjustable portable systems such as SABIX 8 meet different requirements and can be used according to the scale and sensitivity of the treatment.
FEVI professional solutions for restoration
Learn which technology and model to choose for your conservation projects or view the specific systems developed by FEVI for the restoration sector:
