|
Tutorial on carving stone 1. Stones There are major differences between all the stones (granite, marble, limestone, alabaster, slate…). Often, a carver starts with the material which is the most available i.e. limestone, which is a good starting point.
These parameters are crucial to understand as a beginner won’t start carving a block of granite because of its hardness. Some stones weather better than others. For example, a statuary marble is not suitable outdoors but a Carrara C (from Italy) will be fine. A research is needed before starting any project because once the stone is paid, cut to size and delivered, it won’t be easy to return it to the supplier unless he knows you well. It can be even worse if the carved piece shows some signs of bad ageing after only a few months standing in the rain.
Afraid of carving your first project? Try to have a go at wood first, it can be found anywhere. Take a sharp tool, a small piece of soft wood and have a go, it’s easy. Why not considering soap, a candle made of wax for a cheap trial. You’ll get a boost of confidence very quickly. Even a child could do it. If you can buy a few inexpensive kilos of clay and try to find an idea, that would help you a significantly as the idea can be easily changed. Nota: to keep your piece of clay wet, spray it with water before leaving it overnight and put it in a closed plastic bag. That will buy you some time to think about your first project in stone.
Not even a stone in your shopping bag? Well, this material should be easy to find for very little money. As long as there are stone carvers and stone masons in your area, you will be able to get some off-cuts for free. Don’t forget that in their yard, stone masons don’t have much space for the stones they don’t want. Why? When they have to restore a cathedral for example, they buy blocks of stones directly from the quarry. Each piece is about 3-25t. To carve or cut each piece, they saw these huge blocks in smaller blocks to suit their needs. Even if they will try as hard as possible to maximize the cuts to use as much material as they can, they will have to get rid of the material they can’t use for the near future, and can’t store for too long. In the end, they skip what you want: freshly quarried blocks of good stone, with possibly all faces cut which is perfect for any job.
Choosing stones The most important is to get a sound stone. It means that the stone should be free of cracks. To test the stone, take a hammer and gently hit the piece so that it can ring. If it sounds like steel (“ring, ring”) with a clear sound, your stone is good. If the sound is a “toc toc” or “cloc”, the stone can’t resonate well because of a big crack. You should either leave the piece and test another one or try to investigate to see where is the crack. Its location it important. If the crack is at the edge, it will have to come off sooner than later. If it is right in the middle, you’ll have to divide the stone in 2No. pieces. If you don’t separate them, glue them. I don’t like this option as it might be a waste of time working on a bad stone which could result in a broken sculpture later anyway. It is important to know that some stones don’t sound at all. Some alabaster pieces might sound ok but can be cracked because of the nature of the piece. Experience is the only way to know how dangerous a crack is. But usually, an open crack means that it could be a dodgy stone, if it is a closed crack (not through the stone) it might be ok after all. After the hammer test, a close look at every sides of the stone should be done. Search for cracks, discolouring and staining (especially oil contents which penetrate the stone permanently. They can’t be cleaned by a chemical agent. Remove the stained material until a clean stone is emerging). Use water to pour onto larger blocks. If the water gets in the stone and shows a zone which is getting dryer than the rest, there is a crack. In any case, the stone should be clean (meaning free of dirt) for close inspection.
Stone suppliers Any supplier will tell you that his stones are ok for you, they will want to sell what they have, not what you want. Before going to the quarry or the stone yard with a bit of cash in hand, it is best to know what the stone is for. The stone depends on:
Have a chat with the supplier and see what he has. If you are not happy, go and see another one next door. In Carrara & Pietrasanta (Italy), they are hundreds of stone suppliers. Some deal with huge blocks sent all over the world, some suppliers even their own quarries, others saw huge blocks to produce slabs for worktops, other stone suppliers own a sculpture studio. Everyone have different specialities, so looking for a particular piece can be quite hard at first. With the years, it becomes easier to find pieces of raw material by just visiting the stone yards. During summer 2009, I was looking for small blocks of pure white statuary marble (without any veining at all) in the Carrara area. It took me days to source them because nobody had or wanted to sell me the pieces (the studios who carve sculptures don’t like selling their own blocks because they also have difficulties in finding their own stones, especially if they are exceptionally rare. At last, I managed to find a 4No. small blocks by just popping in at new supplier’s premises, after looking hard, I could see the pieces well hidden underneath other stones. About the statuary marble, especially the one from Carrara (the Pietrasanta’s statuary marble is said to be harder) can be cooked (“cotto” in italian), it means that the material is very fragile to abrasion, a file can scrape it very well, which is not good at all. With a hammer you can destroy a stone in seconds. The sound can even be ok, but the material has no strength, this effect can be either localized in a small area or being in the whole block. You should get rid of the bad area (once you’ve bought the piece) or walk away from the block. Still about this particular marble, if you want the best of the best quality (pure white with no black stains), you have to be either patient, wealthy or lucky to get one. Have a very close look at what is shown to you, use a sample of perfect white with you to test its whiteness as there are different degrees of white. It is hard to distinguish how white is a block amongst a huge range of light grey blocks. Remember, all this preliminary work is quite important as the final result will depend on the wise choice of the stone you intent to buy. Regardless of your abilities to turn a rough stone into a master piece, a grey marble will still be a grey sculpture after all the efforts, not a white sculpture. When I want to purchase a few stones, I always have a shopping list with the sizes of each block compiled, a light hammer, my gloves, my tape measure and a file. And of course some money. Finally, if I can’t find what I need, I can either go to another supplier, change my specifications or be patient because the stone might need to be ordered, and that takes time. A large vein of statuary marble is rarely found in a quarry so, when the quality of the marble is not good enough for your requirements, you have to wait for the quarry to progress further, and it take weeks or months to source. |