Techniques - StonePrint this page

Techniques - Stone

  1. The working environnement
  2. The tools
  3. The different types of stones
  4. The stages of a sculpture in direct cut technique
  5. References

Tools to tap

The website http://www.pierres-info.fr/outils/ describes the different tools and how to use them.

Quarry hammers and portuguese hammers

Quarry hammer with a square head
Quarry hammer with a square head
Portuguese hammer with a round head
Portuguese hammer with a round head

First thing the sculptor has to choose is the correct hammer to work easily during long hours. The most important questions to answer are if choosing a quarry hammer or a portuguese one and which weight to choose.

The main difference between quarry hammers and portuguese hammers is the shape of the head, rectangular for the first ones, rounded shape for the second ones. The choice depends on the comfort you feel when holding them.

There are metal-headed hammers (as those on illustrations above) especially to work on stones with metal-handle tools, wood-headed hammers (to use only with wooden-handle tools) to work on wood, but also on very soft stones, but also bronze-headed hammers wich can be used on wood and stones. Again using different types of hammers is the only way to choose your favourite.

Wood-headed hammer
Wood-headed hammer
Bronze-headed hammer
Bronze-headed hammer

Last but not least, the weight of the hammer is very important to consider, if too heavy it's very tiring for the arm, if too light you'll have to hit hard... I generally use different hammers from 300 grammes to 1 kilogramme, depending on the hardness of the stone I'm working on.

Chisels

The first intervention of the sculptor on a stone is to rough it out to the expectated shape. There are several tools that can be used with the hammer to take parts of the stone away.

Point chisel
Point chisel

The point chisel is a tool with a pointed head used to take large pieces off the stone. It is a tool very pleasant to use because he allows to move forward quickly and to apply to the stone a "writing" thanks to the knocks of tools. Be careful on the use of it: always on the bias (never in the perpendicular of the stone, otherwise you might break or mark deeply the stone), always in the direction of the volume (so that the writing is beautiful) and when you approach an edge never towards the outside of the stone (you might break the angle). The work with the point chisel can constitute the whole work of sculpture to obtain a sculpture with knocks of tools which, if they are realized well, can be very beautiful, or it can be followed by work with a riffler (to erase the marks of tool) and of a phase of polishing to obtain a smooth sculpture. In a general way working with the point chisel gives strength to the sculpture.

Tooth chisel
Tooth chisel
Tooth chisel
Tooth chisel

The tooth chisel is a tool which possesses sharp or flat teeth and thus allows to remove large amount of material. It also applies marks of tool that can be kept on the sculpture, but these are less deep and maybe less personal than those obtained by point chisel because they are formed by parallel marks. In soft stones as limestone, the tooth chisel allows to work quickly and effectively and is therefore very generally used as he main working tool.

Attention to use all the width of the head of the tooth chisel when working and not only an angle because you could break a tooth. It is also interesting to know that a used tooth chisel cannot be really sharpened because of its teeth (another good reason to use it on the whole width to keep a regular use of the tool).

Flat chisel for stone sculpture
Flat chisel for stone sculpture

Another very useful tool is the flat chisel (here for stone sculpture) which allows to remove less material than the point chisel, but on a wider surface and by leaving a flatter track. It is thus the tool which is very indicated using after a first rough-hewing and before the use of the riffler. The flat chisel allows to obtain a plane surface.

The other tools (bush hammer…)

Bush hammer
Bush hammer

There are many other tools allowing to work the stone as for example the bush hammer which is a kind of hammer with square head provided with teeth. You apply marks simply by knocking the hammer on the surface of the stone. This tool is used to flatten the surface and create marks of tool on the stone, and not to remove stone pieces. The marks of tools are however regular, what makes that the result is less personal than the one that we can obtain with a good use of the point chisel. Some bush hammers can be equipped with exchangeable heads (teeth are more or less big) which allow to vary drawings on the stone.

Tungsten carbide tools

Some tungsten carbide tools
Some tungsten carbide tools

To work on hard to very hard stones (marble, granite, onyx), it is interesting to use tools with a tungsten carbide point which are more resistant (and thus more long-lasting) and allow to work these stones in a more effective and precise way. These tools have a steel handle in which is set one or several pieces of tungsten carbide, once those pieces are worn out the tool is not usable any more. The carbide sharpens with a specific grindstone. There are versions in the carbide of tungsten of each of the aforementioned tools.

Scrubbing tools

Once the shape of the sculpture was defined well, the sculptor can choose to leave the knocks of tools or to continue his work to obtain a polished sculpture. In this last case he needs to use tools allowing him to rub the stone to remove the knocks of tool and get a flat surface.

Rasps

Various types of rasps
Various types of rasps
Rasp with a bent blade to work easily on large surfaces
Rasp with a bent blade to work easily on large surfaces

There are numerous types of rasps at the disposal of the sculptor to remove the material while flatening. It is necessary to choose a rough enough rasp for the kind of stone you're working on to make the work effective. The choice of a rasp will also have to take into account the shape of this one (flat, rounded off or triangular) who must be adapted to the part of the stone to be worked and its texture which will remove more or less material but will also leave more or less of marks.

Rasps, on the contrary to rifflers, allow to realize easily flat plans, and turns out particularly useful when it is necessary to put a surface on level, for example the bottom of a sculpture so that it is stable.

Riffler

Various types of rifflers
Various types of rifflers
The shapes of rifflers
The shapes of rifflers

Rifflers are very useful to erase the knocks of tools on the surface of the stone and prepare the stone before polishing. They also allow to remove easily and exactly the amount of material on soft stones as the soapstone. The work with rifflers is often quite long because you remove very few material at each time. It is necessary to be patient if the knocks of tool are deep. On the other hand, rifflers allows a much more precise work than tools by percussion, but it is necessary to pay attention to use them well because the plans of a sculpture executed only with rifflers can easily not be well shaped.

There are various shapes of rifflers, made of steel or diamonds (for hard stones), you can choose the most adapted to the realized shape. We can so improve chinks between the volumes (that we call blacks) where the knocks of tool are particularly difficult to pass.

Watch out, riffles quickly wears out and cannot be sharpened, furthermore they can be very expensive! It is important to know that the price range of riffles is very wide (from 10 to 60 euros approximately) according to the quality of these. The experience proves that the price is often justified because the work made with a riffler of good quality is more convincing than with a cheap riffler. The aspect of the stone and the precision of the work will make the difference. However in consideration of the price and the life expectancy of riffles, it can be interesting to use sometimes lower-quality ones (but avoid those who are very cheap, they are generally useless) to rough-out parts of the sculpture, it won't matter so much if they wear out.

Polishing tools

Carborundum stone

A carborundum stone
A carborundum stone

Carborandum stones are made of compressed stone dust. Wet and rubbed against a stone, they sand and polish the stone. Carborandum stones are only used for hard to very hard stones as marble, onyx, granite... They are always used with water (otherwise they will let marks on the stone!), the friction removes some stone and turns it into a dough. It is a rather long and tiring work, but for hard stones it is the most effective way to erase tracks left by the other tools and to prepare the stone to the next step of the polishing.

To clean chinks between several volumes, the carborundum is often rather difficult to use because of its shape and its rigidity, it is then recommended during the work on the plane surfaces of the sculpture to wear out the angles of the carborundum to create sharp angles able to go into the chinks.

There are various grains (same as sandpaper), you have to use them from the roughest to the finest, the first one removing the various marks made by the previous tools (be careful to remove all the marks because the following carborundum will be too fine to erase them!) the following carborundums removing tracks left by the previous ones. I used carborundum in grains 320, 400 and 600, enough to me for a marble sculpture. On the other hand I used much rougher grains to polish a granite pebble (grains 24 and 36).

The carborundums of various grains are generally differentiated by a mark and by their color, but as it quickly wears out, you might forget the color-grain correspondence, it might be a good idea to write it down!

Sandpapers

Wetable sandpaper
Wetable sandpaper

To polish a stone you have to use sandpaper with water (using water avoids marks), it is then necessary to choose wetable sandpaper otherwise the paper will split immediately when you'll put it into water. As for riffles my experience tought me to choose good quality paper, more expensive but more long-lasting. I generally use the brand 3M.

The polishing is made by successive work with sandpapers of different grains from the roughest to the finest. Grains I'm usually using are: 220, 320, 400, 600, 800, 1000, on 1200. For a soft stone, the polishing can begin with of 320. The sandpaper is an essential stage of the work of the sculpture because it's the moment when the surface done will let the light emphasizes volumes and the blacks of the sculpture.

Polishing paste and wax

Polishing paste compound
Polishing paste compound
Felt disk to use on a drill
Felt disk to use on a drill

The last stage consists in protecting and making the perfectly polished sculpture shine, two products can be used for it, the polishing paste or the wax.

The polishing paste must be applied with a slow rotation drill or grinder (or a mini-drill for the very small sculptures) with a felt disk on a plate fixed to the chuck. The felt disk rubbed first on the briquette to coat it with the paste and then on the whole sculpture, always following the volumes and without forgetting chinks. This is particularly adapted for stones as alabaster or soapstone.

An other solution, simpler, consists in using good quality wax (be careful to choose a colorless wax!) to protect and make the stone shine. Apply the wax without excess because, contrary to the wood, the stone does not absorb the wax. It can be applied with a clean cloth (not to mark the stone) then, when dry, polished with a felt disk or more simply with a woolen cloth to make the surface shine.

Electrical and pneumatic tools

The sculpture of very hard or huge stones can be made with electric tools such as drills, sanders or grinders. However, whatever tool you're using, the advices given in this article must be respected (work by plans and wide movements) because it is very easy to make involuntary hollows in a sculpture with such tools. Thus be sure to understand and follow them before beginning.

Attention also on all the safety instructions about the tool you're using, it is essential to respect them to avoid any accident. protections for eyes, ears, respiratory system and hands are also essential.

The drills

Les disqueuses

Les ponceuses

Les outils pneumatiques

L'outillage miniature

The mini-drills

Box containing a mini-drill and many accessories
Box containing a mini-drill and many accessories
Work on wood with a Dremel Fortiflex
Work on wood with a Dremel Fortiflex

Mini-drills are useful accessories for a sculptor because you can work very precisely with them even on very small details. There are many accessories for multiple uses, sometimes very distant from the sculpture (they are originally designed for model making). If you buy a box (always interesting because accessories are very expensive) there will probably be a lot of them you will never use.

Mini-drills are obviously only used on rather small sculptures. It is important to master well this tool to avoid creating holes and marks in the sculpture (it is not always easy because the engine turns fast, it is necessary to hold the tool well and to measure the pressure on the stone to make sure it's constant) the best way being to respect good sculpting practicesin general(wide movements for the realization of the plans, always in movement by working plan by plan before getting into the details). Last advice: use a little the tool before begining a sculpture to get used to it.

Rotating tools with hoses

The Movix tool from Moviluty brand
The Movix tool from Moviluty brand
Working on a piece of wood with the Dremel Fortiflex
Working on a piece of wood with the Dremel Fortiflex

The Dremel brand (well known) proposes a mini-drill specialized in sculpture called Fortiflex with characteristics and accessories well adapted to the work of sculpture on wood and stone. Furthermore it is equipped with a standard chuck what allows to adapt other bands' tools (very useful because Dremel accesories are expensive and you can find equivalent tools in specialized stores). It is also equipped with a flexible arm which makes it easier to hold and with a pedal which allows to vary very finely the rotation speed to adapt it to the work to be done. I'm writing about this model because it is the one I'm using when I need a small electric tool (making a hole in a sculpture, signature, polishing...), what is not often because in general I prefer to work with non electric tools...

For an intensive use, the range of products of the brand Moviluty is very adapted because more powerful, with a wider chuck and more possibilities in terms of tools. The Movix version is a very good professional tool. It's also interresting to know that there is a hitting handle which can be adapted on the hose to transform the rotation of the tool into percussion, which can always be useful, even if it is better if you're using often the percussion to choose a vibrating tool.

The main tools used for stone

Percer
1. To drill

 

To cut
2. To cut

 

To grind
3. To grind

 

To sand
4. To sand

 

To polish
5. To polish

 

To sharpen
6. To sharpen

We shall find the accessories equivalent to all the tools necessary for sculpture: drills, grindstones to remove material, carborundum stones and sandpapers, polishing disks and polishing paste... All of them in a whole outfit of grains, sizes and forms. There are also various models of tungsten carbide and diamond tools to work on very hard stones.

  1. The drills are very useful for the soclage of small size sculptures for which using a standard drill is difficult and lacks of precision. Drills exists from 2mm to 6mm diameter and allow, thanks to the precision of the hose to make very clean and straight drillings.
  2. Cutting disks allow to rough-hew the stone by removing big quantities of material quickly and with a clean edge so that the cutted part can be reused to create another sculpture.
  3. Grindstones allow to remove a lot of material and are thus the main tool used by the sculptor for the realization of the sculpture. Various forms allow to adapt to the shape of the sculpture and to reach even hard to reach zones. Attention however not to be overtaken by the tool which rotates fast and removes the material very quickly. If you remain too long on a point of the sculpture, it will create a hole which will be very difficult to make disappear, the best advice is again to always work with large and constant movements.
  4. Sanding tools correspond to the stage sandpaper of the sculpture to remove the small scratches left by the grinding tools.
  5. The polishing tools allow to make the sculpture shine with some polishing paste.
  6. Sharpening tools can also be useful, for instance when the edge of a gouge is too much damaged to be sharpened with a simple grindstone (even if nothing replaces a bench grinder).

Manufacturers' websites propose pages to find the right tool for the right use, a very interesting feature because their descriptive system on tools is sometimes at least difficult to understand...

You'll find this page on the Dremel website at the address: http://www.dremeleurope.com/dremelocs-fr/category/2823/trouver-les-bons-accessoires and on the Movilux website at the address: http://www.moviluty.fr/MOVILUTYensembfiches.pdf.

The mini-grinders

Arbortech mini-grinder
Arbortech mini-grinder

The Arbortech brand proposes a mini-grinder created for precise work on wood. It allows the use of small disks of 40mm diameter fixed at the end of an arm which allows a precise approach of the details of the sculpture. This tool can be also adapted for the work of stone. Several types of disks can be adapted on this tool.

 

  1. Steel disks : To work on soft woods.
  2. Tungsten carbide disks : to work on hard woods and soft limestone.
  3. Diamond disks : for the hardest materials such as stone, metals, hard plastics and glass.
  4. Grinding disks : different grains depending on the finition needed, grains : 40, 60, 80 and 120.

Vibrating tools

Bordet vibrating toot
Bordet vibrating toot
Artistix Piccolo electric vibrating tool
Artistix Piccolo electric vibrating tool

There are tools that allow to turn the electric rotation into vibrations to sketch quickly and easily all the materials, especially hard stones and woods. These vibrations turn the electric tool into a tool which approaches the possibilities of a pneumatic tool.

The Bordet vibrating tool is weel known for its qualities which makes it an interesting purchase for a many sculptors despite its expensive cost.

The Artistix Piccolo tool, you can purchase in Boesner shops, is interesting beacause it combines the possibilities of a rotating machine with hose and those of a vibrating tool. To note that the rotary machines with hose of the brand Moviluty can be also completed by a hard-hitting handle.

 

 

 

The working environnement Read more: The working environnement

Read more: The different types of stones The different types of stones

 

 

Close windowPrevious imageNext image