A blasting machine for restoration must make it possible to remove deposits, blackening, oxidation and old coatings while maintaining maximum control over the original material. The choice depends on the state of conservation of the substrate, the size of the area, the type of contamination and the degree of precision required. For details, engravings and small artefacts, a microblasting machine may be suitable; for larger surfaces, an adjustable portable machine may be required, while a recovery system helps contain abrasive and dust. Dry ice cleaning can be assessed when it is necessary to avoid water, detergents and residues from the cleaning medium.
Where blasting is used in restoration
In the restoration sector, microblasting and controlled blasting can be used for the treatment of:
- ✓ Architectural elements, stone artefacts and marble
- ✓ Natural stone, terracotta, brick and wood
- ✓ Metals, statues, bas-reliefs and frames
- ✓ Decorations, finds and funerary elements
- ✓ Mosaics, historical-furniture components and artistic surfaces
FEVI identifies precision, jet adjustment and adaptability to delicate materials as the main criteria for choosing the machine. The aim is not simply to make the surface look new. A restoration operation may be intended to:
- ✓ Remove a foreign deposit or reduce blackening
- ✓ Restore the legibility of a decoration
- ✓ Remove an old incompatible finish
- ✓ Remove oxides from a metal component
- ✓ Clean a detail without altering the surrounding areas
- ✓ Treat the surface before consolidation
- ✓ Improve adhesion for a subsequent conservation treatment
- ✓ Preserve the patina when it represents a significant part of the object’s history
Conservation restoration and simple renewal are not the same thing
When renewing a recent surface, removing part of the outer layer to obtain a uniform result may be acceptable. In conservation restoration, however, the surface layer may contain traces of the original workmanship, historical finishes, patinas, pigments, engravings, signs of use and information useful for reading the artefact. A treatment that is technically effective in removing dirt may therefore be incorrect from a conservation perspective if it also removes original material. Before choosing the machine and abrasive, it is necessary to establish which element must be removed and which must be preserved.
The principle of minimum intensity
The correct approach is to start from the least aggressive combination capable of producing a measurable result. Adjustments are made progressively on:
Any increase in intensity must be gradual and justified by the behaviour observed during the sample test. Maximum removal capacity is not an advantage when the original material is delicate, ancient or already degraded.
Which materials can be treated
The historical-restoration sector combines fragile and unique substrates that require detailed diagnosis and mapping:
Natural stone and marble
The term natural stone includes granite, marble, travertine, sandstone, limestone, slate, porphyry, local stones and historical agglomerates. Before processing, hardness, porosity, cohesion, presence of fractures, exfoliation, erosion, crusts, previous treatments, any consolidants, original finish and historical value must be assessed. A compact stone may tolerate a process that would be excessive on soft sandstone or on already decohered limestone.
Marble may be affected by blackening, surface deposits, oxidation from metal elements, wax residues, old finishes, pigments, encrustations and graffiti. The treatment must take into account the original finish: a polished, honed or bush-hammered surface cannot be treated with the same parameters. An incorrect abrasive can dull the marble or permanently change its reflection.
Terracotta and ancient brick
Terracotta and brick may have a relatively resistant surface or may be friable, flaking, highly porous, affected by efflorescence, worn, previously treated or covered with paints or waxes. Excessive processing can remove the more compact outer layer, increase porosity and make the material more vulnerable to water and freeze-thaw cycles. Technical sources dedicated to historic masonry conservation report that aggressive abrasive cleaning can remove the resistant outer surface of the brick and expose its softer core.
Wood
In wood restoration, controlled blasting can be used to remove old paints, eliminate surface residues, clean engravings, highlight the grain, treat beams, restore shutters and window frames or work on furniture and components. Softwoods, hardwoods, solid wood, veneered wood or already degraded wood react differently. A jet that is too aggressive can erode softer fibres, create excessive relief, round edges, erase details, go through veneer or highlight defects that cannot be recovered. On decorated, gilded, polychrome or veneered elements, the operation must be assessed by a specialised restorer and cannot be generalised.
Metals
Microblasting can be used on iron, steel, bronze, brass, copper, aluminium, alloys, small components and historic hardware to help remove oxidation, rust, residues, old coatings or localised contamination. The treatment must be compatible with thickness, hardness, finish, decorations, patina, any historical value and subsequent protective cycle. In the case of bronzes and ancient alloys, patina may have historical value and must not automatically be interpreted as dirt to be removed.
Ceramic, mosaic and composite materials
Microblasting can be assessed on small areas of ceramic, resin and mosaic, but requires accurate diagnosis. Tile adhesion, presence of glazes, condition of joints, crazing, previous integrations, pigment sensitivity and differences in hardness between materials must be checked. A configuration suitable for the tessera may be too aggressive for the joint or for a restoration filler.
Analysis of surface contaminants
The selective process must isolate and remove only the accumulated foreign fraction:
- Surface deposits and blackening: These include consolidated dust, atmospheric particulate, soot, adhering dirt, organic residues and products applied during previous maintenance. Blackening may be superficial or associated with transformations of the material. A crust does not necessarily have to be removed completely: it may be useful to reduce its thickness without reaching the intact substrate.
- Old paints and coatings: The result depends on composition, number of layers, adhesion, elasticity, penetration into pores and substrate resistance. Simply increasing pressure can damage the surface before removing the coating.
- Metal oxidation: Before removing rust or corrosion products from metals and components, it is necessary to distinguish carefully between active corrosion, stable patina and any historically significant traces.
- Graffiti on historic walls: These require particular caution. Paint and pigments penetrate the porosity of stone, marble and terracotta. Technical guidance on graffiti removal from historic masonry recommends choosing the least aggressive method, because forced high-pressure removal can cause damage more visible than the remaining graffiti.
Which technology to use in restoration
The technical responses vary according to the scale of the intervention and the artefact’s water sensitivity:
Precision microblasting
Microblasting uses a concentrated jet, fine abrasives and small-diameter nozzles. It is suitable for details, engravings, small surfaces, delicate artefacts, sculpted elements, selective work, localised deposit removal, laboratory use and operations where productivity is not the main criterion. The main advantage is the possibility of working progressively on a reduced area. The limitation is productivity on extensive surfaces, where it does not replace an open-blasting machine.
Low-intensity portable blasting
An adjustable portable blasting machine makes it possible to treat larger surfaces than a microblasting machine while maintaining good control of the parameters. It may be suitable for stone elements, undecorated historical façades, beams, wooden artefacts, terracotta, metals, architectural components and site work. The machine must allow precise adjustment of pressure, abrasive, dosage, distance and intensity. Where possible, abrasive dampening can help contain particle dispersion, but the artefact’s compatibility with water must be verified.
Recovery blasting
The recovery system uses a head kept in contact with the surface. During processing, abrasive, dust and residues are drawn back. It may be suitable for localised operations, fairly regular surfaces, indoor environments, sites where dispersion must be contained, architectural elements or limited portions. The main limitation concerns geometry: deep reliefs, engravings, edges and recesses can prevent the head from maintaining correct contact.
Dry ice cleaning
Dry ice cleaning uses solid carbon dioxide pellets carried by compressed air. The process uses no mineral abrasive, water or detergents, and the dry ice sublimates after impact, leaving no cleaning-medium residue. It may be assessed for organic residues, soot, grease, waxes, components and surfaces compatible with thermal shock where water must be avoided. It is not a universal replacement for microblasting: it may be less effective on mineral encrustations or highly resistant oxides. On fragile or layered materials, a thermal technical test is essential before starting.
Adjustment criteria for microjets: nozzles and compressor
The choice of abrasive must consider hardness, particle size, shape, friability and grain purity. Fine abrasives concentrate the flow, but the definition of “delicate abrasive” alone does not guarantee safety: even a soft material can damage a friable surface if used with incorrect distances or exposure times. Compressed air must be stable, dry and completely free from condensate to prevent abrasive agglomeration and clogging of micro-nozzles. The compressor must be calculated on the real consumption of the nozzle to avoid pressure fluctuations that would prevent faithful replication of the parameters established in the preliminary sample.
How to choose the technology: decision table
| Requirement | Indicative technology | Why | Aspects to check |
|---|---|---|---|
| Details, engravings and small areas | Microblasting | Concentrated and controllable jet | Abrasive, nozzle, pressure and substrate stability |
| Medium-sized artefacts and surfaces | Adjustable portable blasting machine | Greater productivity than microjet work | Delicacy, compressor and dispersion |
| Localised work in an indoor environment | Recovery blasting machine | Contains a significant part of abrasive and dust | Head adhesion and geometry |
| Delicate and compatible surface | Low-intensity microjet | Allows progressive passes | Sample and analysis of the state of conservation |
| Organic residues without using water | Dry ice cleaning | Leaves no cleaning-medium residue | Thermal shock, ventilation and contaminant |
| Sculpted stone with complex geometry | Microjet or controlled open blasting | Reaches engravings and recesses | Protection of the areas to be preserved |
| Metal element with localised oxidation | Microblasting | Allows a selective intervention | Patina, alloy and subsequent protection |
| Flat area with residues to contain | Integrated recovery | Reduces dispersion into the environment | Surface regularity |
| Medium-sized beam or wooden artefact | Adjustable open blasting | Covers a larger surface | Wood species, fibres, paint and risk of erosion |
| Small component sensitive to water | Dry ice cleaning | Dry process | Thermal compatibility and adhesion of details |
Four FEVI models recommended for restoration
1. MICRO BLASTER – Precision microblasting machine
For details, engravings and small artefacts
MICRO BLASTER is a portable microblasting machine designed for localised work requiring accurate control of the abrasive jet. The micro-projector allows treatment to be concentrated on limited areas, details, edges and engravings, using small-diameter nozzles and selected fine abrasives.
Uses in restoration: Small stone artefacts, sculpted details, engravings, marble, stone, ceramic, mosaics, metals, wood, finds, decorative elements and precision laboratory work.
Strength: The surgical precision of the microjet allows work on limited areas without involving the surrounding zones.
Limit to assess: It is not designed for large surfaces or for operations where productivity is the main criterion. It requires constant verification of abrasive hardness, distances and substrate stability.
Recommended user: Restorers, artistic laboratories, marble workshops, cultural-heritage professionals and companies carrying out highly selective treatments.
2. SABIX 8 – Portable open-blasting machine
For controlled work on larger surfaces
SABIX 8 is a professional portable open-blasting machine, suitable for low-intensity blasting, microblasting, restoration and controlled site work. It features fine abrasive-flow adjustment, works with low airflows and can integrate the Acquablast dampening system.
Uses in restoration: Architectural elements, stone, marble, terracotta, brick, wood, metal, undecorated historical façades, beams and medium-sized artefacts directly on site.
Strength: It offers an excellent balance between transportability, load autonomy, fine adjustment and the possibility of working with a dampened jet.
Limit to assess: Compared with a microblasting machine, it produces a wider jet and requires greater attention when working close to complex decorations or fragile edges.
Recommended user: Site-restoration companies, construction companies specialising in historical recovery, stone laboratories and restoration carpenters.
3. SABIX R – Portable recovery blasting machine
For localised operations with greater residue control
SABIX R is a portable recovery blasting machine that can also be converted into open-blasting mode when required. The system allows abrasive and removal residues to be extracted simultaneously and conveyed into the tank to reduce dispersion.
Uses in restoration: Flat architectural elements, stone surfaces, façade portions, indoor environments, on-site operations and regular surfaces on which the head can maintain perfect adhesion.
Strength: It combines portability, reduction of airborne dust, abrasive recovery and flexibility of conversion to open blasting in a single solution.
Limit to assess: The recovery head loses effectiveness in the presence of deep reliefs, undercuts, sharp edges or complex engravings, situations in which the machine must be switched to open-blasting mode.
Recommended user: Restoration companies, maintenance technicians, operators working indoors or in inhabited areas where dust must be contained and order preserved.
4. SUBLIMA MINI – Dry ice blasting machine
For dry cleaning without mineral abrasive
SUBLIMA MINI is a compact dry ice blasting machine that uses solid carbon dioxide pellets carried by the airflow. The machine operates without water, detergents or cleaning-medium residues, because the ice sublimates and disappears after impact.
Uses in restoration: Removal of organic residues, fire soot, waxes, grease, contamination on historic metals and situations where the use of water or mineral abrasives is strictly prohibited.
Strength: It provides completely dry, localised cleaning, without detergents and without the need to collect spent cleaning agent.
Limit to assess: It does not develop the same abrasive action as a micro-projector: it is not suitable for resistant mineral crusts or deep oxides. The compatibility of fragile or layered substrates with thermal shock must always be validated.
Recommended user: Specialist restorers, cultural-heritage laboratories, special-maintenance companies or companies working on sensitive electronic components or historical systems.
FEVI model comparison table
| Model | Technology | Recommended use | Strength | Limit to assess |
|---|---|---|---|---|
| MICRO BLASTER | Microblasting | Details, engravings and small artefacts | Microjet precision | Limited productivity on extensive surfaces |
| SABIX 8 | Adjustable open blasting | Small or medium-sized artefacts and surfaces | Balance between control and productivity | Larger impact area than microjet work |
| SABIX R | Recovery system convertible to open blasting | Localised operations and environments to be kept orderly | Abrasive recovery and flexibility | Difficulty on very irregular geometries |
| SUBLIMA MINI | Dry ice cleaning | Organic residues and water-sensitive surfaces | No cleaning-medium residue | Does not replace abrasive action |
Frequent mistakes to avoid in conservation restoration
The protection of historical artefacts requires the elimination of invasive mechanical behaviours:
- Confusing cleaning with complete removal: Removing every single visible trace to make the substrate look “new” is conceptually wrong. Historical patinas, ancient finishes or marks left by the original chisels belong to the memory of the piece and must be preserved.
- Choosing the machine only on the basis of minimum pressure: Working at low pressure does not guarantee absence of damage if the operator uses an abrasive that is too hard, an unsuitable nozzle or insists at excessively short distances, creating cavities or colour changes.
- Insisting on deeply penetrated contamination: When graffiti pigments or pollutants have penetrated the pores of soft stones, increasing exposure time destroys and wears the mineral substrate without extracting the colour.
- Not distinguishing stable patina from active corrosion products: In bronzes and ancient metal alloys, oxidation patina protects the metal and has documentary value; it must not be confused with common dirt.
- Underestimating air quality or failing to document samples: Humid air agglomerates fine abrasives, blocking micro-projectors. In addition, if pressures, nozzles and distances used in the test patch are not recorded, replicating the result on the entire object becomes impossible.
- Using systems disproportionate to the geometries: Using a microblasting machine on entire façades makes the work uneven and slow; conversely, excessively wide and productive jets on details hit and degrade adjacent areas that must be preserved.
FAQ on blasting machines for restoration
Which FEVI blasting machine is most suitable for details and bas-reliefs?
MICRO BLASTER is the solution most oriented towards details, engravings, small surfaces and selective work. The micro-projector allows the jet to be concentrated on a reduced area and fine abrasives to be used. However, machine precision does not eliminate the risk of damage: pressure, abrasive, nozzle and distance must be defined through tests. If the surface is more extensive, SABIX 8 can offer greater productivity while maintaining good adjustability.
Which model should be chosen for working directly on restoration sites?
For small and medium-scale site work, SABIX 8 can be assessed because it combines transportability, jet adjustment and greater autonomy than a microblasting machine. When containing abrasive and dust is important, SABIX R may be preferable. The choice depends on geometry: recovery works best on fairly regular surfaces, while open blasting more easily reaches engravings, recesses and edges.
Does microblasting always guarantee a delicate and safe operation?
No. Microblasting offers superior control of the treated area, but remains a mechanical abrasive process. A hard abrasive, excessive pressure, a nozzle that is too close or prolonged exposure can etch even a resistant surface. Delicacy comes from the overall configuration and from the operator’s ability to proceed through progressive samples. On friable, decorated, polychrome or already consolidated materials, specialist assessment is necessary before proceeding.
When is it advisable to choose the SABIX R recovery blasting machine?
SABIX R is suitable when the work is localised and the abrasive needs to be recovered during treatment. It can be useful indoors, on architectural elements and on relatively regular surfaces. If deep reliefs, undercuts and complex decorations are present, the head may not adhere correctly. In these cases, the machine can be converted to open-blasting mode or a microblasting machine such as MICRO BLASTER can be assessed.
In which cases is dry ice application with SUBLIMA MINI optimal?
SUBLIMA MINI can be assessed when soot, waxes, grease or organic residues need to be removed without using water, detergents or mineral abrasives. Dry ice leaves no cleaning-medium residue because it sublimates, but the process still exerts impact and thermal stress on the surface. The technology must therefore be tested on the actual material. It is not suitable for mineral crusts, resistant oxides or treatments requiring true abrasive roughening action.
Tell us the requirements of your restoration operation
The selective removal of soot patinas or coherent deposits from a delicate stone bas-relief requires configurations, nozzles and abrasives that are opposite to those needed for removing oxides from historic hardware or cleaning large wooden beams. The optimal choice between MICRO BLASTER, SABIX 8, SABIX R and SUBLIMA MINI depends on the material, contamination and level of precision required. To define the correct setup and help avoid irreversible abrasion of the substrate, tell us the artefact material, its dimensions, current state of conservation, the type of deposit or old coating to be removed, the sensitive areas to be preserved and the compressor available in your laboratory or on site.
FEVI verifies together with the user the technology, abrasive, nozzle, pressure and accessories most consistent with the operation, always starting from a controlled test on a limited area.
