FREQUENTLY ASKED QUESTIONS
The following questions are frequently asked our Staff. if you have any additional questions not posed here, please don't hesitate to contact us.
STONE CARVING
What is the difference between alabaster, marble, and soapstone as far as hardness is concerned?
The softest stone is soapstone, yet there are different hardnesses of this material. The next hardest stone is alabaster and is considered a medium hard stone. Marble is the hardest of the group and has different hardnesses depending on where it is quarried, Colorado, Vermont, Spain, Italy, or Portugal. In addition to these stones there is granite which is extremely hard and not recommended for the average carver. Fieldstone is a “don’t touch” stone for carving. Wonder stone (soft), Feather Rock (volcanic ash), and Maple Rock (compressed clay, unfired) are specialty stones and are generally hard to find.
What are the steps in stone carving?
The basic steps are design, percussion removal in 3 stages (roughing, secondary shaping and smooth finish), hand rasping, sanding, and finally finishing and mounting.
What tools do I use in stone carving?
The stone carving tools used to perform these functions are considered handheld unless specifically described as pneumatic or electric. The basic tools needed are the point, rake (tooth chisel), the flat straight chisel and a hammer, all of varying sizes and weights. All are made of high carbon steel.
What are these primary tools used for?
The point removes the primary bulk material and comes in three sizes, small, medium and large. The tooth chisel or rake, for the second stage of removal, is a flat straight chisel with slightly beveled teeth. It is principally used in the geometric reduction of a larger piece of stone. The straight chisel is the finishing tool used before the final abrasive finishing, rasping, and sanding.
As these are handheld tools, the hammer is used to properly strike them during carving.
What is a rasp?
Rasps are devices used in the finishing process after basic carving is completed. These can be used for reducing wood and stone and are sometimes used in finishing metal. They are double-ended tools with small, medium, or large teeth and are made by hand, each tooth hand punched. Most rasps have a radial curve on at least one side but some may be flat. The teeth are located on both sides as well as on the edges.
Why do rasps wear out so fast?
There are several factors that affect the wear and tear of rasps. One, is the quality, hardness and tempering of the steel used to produce the rasp. Two, is the hardness of the surface and the purity of the stone being rasped. Three, is the pressure applied by the sculptor in using the rasp. And four, over time, rasps will eventually wear out. To prolong the life of your rasp, regular cleaning of the rasp's teeth with a rasp brush will remove any debris accumulated among the teeth allowing for cleaner and more effective rasping.
Why do some rasps wear faster than others?
The temper determines the hardness of the steel cutting edges and their ability to hold up under rasping. The hardness and coarseness of the stone being carved is also a large factor; for example, sandstone will wear out a rasp faster than a soft soapstone. Tooth size and firmness of stroke have a minor effect. Some think that manufacturers offer tools of different quality, but if the proper steel and temper are used they should all hold up equally well.
Why do tools chip off teeth or chip on their edges?
This happens quite often to beginners who do not know how, or at what angle, to hold the tools, or the strength they should use when hitting with them. Usually the end teeth or left and right sides of the tool are damaged, rarely the center teeth or midsection of the tool. Most damage is done due to the inexperience of the user, not the quality of the tool. With practice, the beginner will hone his or her skills to prevent this from happening.
How do I sharpen my tools?
Most tools are sharpened on a bench stone or a combination bench stone (a sharpening stone with two coarsenesses). For gouges and parting tools a specifically shaped sharpening stone is used. The sharpening process is done at 45° angle to the stone and in a figure eight rotation.
Is there a difference in temper between wood and stone tools?
Yes. The stone tools are slightly harder due to the wear demanded of them. Consequently they must also be sharpened more often.
What is the best all around pneumatic handpiece?
The 5/8 or 1/2 inch handpieces are the most commonly used because of their size and weight.
What stone and types of tools would be good for carving letters?
The best stone for carving letters would naturally be a harder stone; a good all-around stone that is easy to carve is alabaster. The specific tools are the smaller flat chisel and miniature stone carving tools available individually or in a set. Carving letters takes some practice since the ends of the letters tend to chip; that is why you see roman letters with a small tang on the ends.
