by DLSproule
When I started sculpting, I had a claw hammer, a set of four wood chisels and a big chunk of soapstone. I thought that was a good start – but I was wrong. There is one tool that is absolutely essential for any stone carver that I did not even know about. Do you know what that tool is?
If you guessed point chisel, give yourself a gold star. Out of all the chisels, a point chisel is the one least likely to split or break the stone in a catastrophic or unexpected way. Wood chisels are flat or blade chisels. If you hit any stone the wrong way or in the wrong spot with a flat chisel, it is like a wood splitter and it will often cleave the stone, breaking it in half or shearing off a large piece in a way you usually don’t expect and probably will not appreciate.
Point chisels are masonry tools – made for breaking stone in a very controlled way. If a mason wants to dig a hole into stone or concrete, he/she would use a point chisel. With a point chisel, the impact is spread out from a very tiny central point, which will generally chip rather than split a stone. Although splitting can occur when you’re using a point chisel, the effect is more like driving in a nail than hitting it with an axe.
The most effective way of using a point chisel for shaping is cutting lines about ½ deep in a crosshatch pattern and then using a flat chisel to smooth the crosshatched surface.
This is not a difficult or particularly time consuming process with most stones – depending on the hardness of the stone.
Talc is the softest known mineral. It’s the stuff talcum powder is made from – so you’re carving the same stuff you’d put on your baby’s bum. It doesn’t seem like much of a challenge, but you’d be surprised. Pure talc is 1 on the hardness scale and can be broken by almost any impact from almost any tool. It is not a great carving stone, although it is possible to create sculptures using files, rasps, rifflers and even knives. A finished sculpture made of talc can be easily damaged by scratching it with a fingernail (which is considered to be about 2.5 on the hardness scale).
Soapstones – which contain anywhere from 20 to 99% talc – can reach up to 4 on the Mohr’s Hardness Scale depending on the amount of talc they contain. On the softer stones, you may want to avoid chisels altogether, but when chisels are required, you will need a point chisel for shaping the stone.
Unexpected breaking and fracturing decreases with the hardness of the stone (this is not so true with very hard or crystalline stone). So a soapstone with (approx) 50% talc will usually be much more fun to work with than pure talc. Most stone is made of a mixture of different minerals – which accounts for its colour and hardness. Sculptors often use harder stones like serpentine – which ranges from 2.5 to 5.5 on the Moh’s scale – and marble (which is mostly calcite) usually ranges from 3 to 5. Granite – with a hardness starting at 6 – is too hard to work effectively with hand tools.
It is not unusual to encounter different hardnesses within the same stone, so if you’ve been bashing away on a dark green part of the stone and encounter a streak of light green or yellow, you may find that it becomes suddenly and dramatically harder. You’ll probably also find stone that is peppered with iron, for instance, which would likely give you flecks of very hard black stone surrounded by much softer cream coloured stone – making it very difficult to get a smooth surface when you’re finishing your sculpture.
These are all things you will likely encounter the longer you continue as a stone sculptor.
