CARVING SKULLS & STUFF (11-FEB-08)
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GENERAL:

This is intended as a continuing project. I'll be adding to it, and editing it for greater clarity, in response to your comments and questions. So if something is left out, or not clear, please let me know. Eventually, this may turn into a proper tutorial, but I'm starting out small, so that people who are asking questions don't have to wait until that possibly distant time. And so people can tell me what they actually need to know.

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SAFETY:

Goggles -- I don't carve unless I'm wearing some sort of eye protection, usually magnifying goggles (because I'm getting old and can't focus up close anymore), but sometimes non-magnifying ones. Chunks of stuff can fly about, and you don't want them in your eyes.

Respirator or dust mask -- Dust is not good for your lungs, and power carving can produce lots of dust. The dust of bone, antler, and shell is very bad; it can _permanently_ clog parts of your lungs. Many stone and some wood dusts are toxic, and large quantities of dust are just generally to be avoided. Use breathing protection. And an exhaust fan and/or vacuum trap for dust is recommended. I use a respirator with replaceable filters.

Ear Protectors -- A constant sound of the same pitch can wear out part of your hearing, even at low volume, and loud sounds do it faster. I have a pair of ear protectors of the sort sold for use at gun practice, which I don't always remember to use.

Foot control -- A foot pedal to aadjust speed, or at least a foot on-off switch, is not only for better control and convenience in power carving, but is good to have if a power tool gets away from you, or something startling and unforeseen happens. All my power tools have either a foot pedal or foot switch. I made a foot switch for a friend's drill press, for emergency stops, and it was needed.

Technique -- I try to use tools in such a way that if the work cracks or slips, or a power bit "grabs" the material and pulls itself along (very common with antler), the tool will not hit something important, particularly me.

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TOOLS:

I have a Foredom flex-shaft machine. This is a big, powerful motor that hangs on a hook, or sits on a base, with a long, flexible shaft attached. Various handpieces can be snapped onto the end of the flex-shaft, to hold rotory tools (one actually converts the rotation to a hammering motion). I use mainly a handpiece with a chuck like an electric drill, so I can use non-standard cutters, and small drills. Foredom isn't the only company that makes flex-shaft machines, but most jewelers I know use Foredom. One advantage of a flex-shaft is that you can have a more powerful motor than would be convenient to hold in your hand. Another is that when carving under water (which is how I carve most stones), water doesn't get splashed into the motor.

I also have a micromotor. It looks something like a Dremel tool, but is much smaller and lighter, and (most importantly) rotates _very_ fast. It's my best tool for detail work on wood, antler, or bone. Otto Frei, the local jewelers' supply (where I got the current chuck handpiece for my Foredom) has a couple of brands of micromotor. They are expensive, and I haven't tried either brand. The one I have is a Bell International model 8L "hand engine" used by plastic surgeons, veternarians, etc. (the apparatus used by dentists to drill and carve your teeth is called an "engine".) I couldn't have afforded to buy it new (got it second-hand at a big antique show). Other companies make surgical / dental hand engines, too, but I don't think anyone makes a cheap model.
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Foredom: http://www.blackstoneind.com/foundations/store/home.asp
Otto Frei - Jewelers Tools & Findings: http://www.ottofrei.com/
Watchmakers Tools & Findings: http://www.ofrei.com/
Robbins Instruments: http://www.robbinsinstruments.com/equipment/handengine/handengine.html

And I do have a Dremel tool. And an electric drill.
Dremel: http://www.dremel.com/en-US

To go in my power tools, I have several hundred cutters, abrasive points, drills, etc. in different sizes, shapes, and materials. Most of the tiny metal and carbide cutters were made for dental work. Most of the larger ones are from Foredom and Dremel.

I also have several hundred hand tools: swiss pattern files, engraver's burins, knives, saws, points, brushes, clamps, etc., etc., etc.

If this vast array of tools seems daunting, note that the fox skull in my gallery was carved with one small ball-end tool for the spirals and curved lines, and one small cylinder burr for the edges of the forehead oval and the cord holes. I used the Foredom, but a Dremel would have worked. And the cast resin puma skull (werewolf tribal fetish - puma) was done (except for the bone inlay and its socket) with a single engraver's burin. Sometimes the simple way is best.

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SKULLS:

Prep Work:

Removing the bodies of dead insects (I have some nice surgical tools for getting them out of difficult to reach places, like the turbinate bones*), taking off any mummified gristle (dentist's tooth-cleaning tools), smoothing rough or excessively pointy bits (small files, Scotch-brite pads), gluing loose teeth or popped-open seams (cyanoacrylate, a.k.a. Crazy Glue -- read and follow the safety precautions. I have acetone handy to dissolve it off my fingers, and I wear goggles so I don't get it in my eyes.)

*Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in humans and other vertebrates.

Carving:

Bone, when in good condition, is hard and tough, but not gummy. It carves easily with high-speed tools; and slower speeds work too, if you are patient. Tools with smaller teeth seem to work best. With practice, I've gotten a feel for how much pressure I can use, and how much thickness of bone I have to work with in a particular area. With skulls, the answer to both is usually "not much". Small skulls are generally thin, getting their strength from their curvature, like an eggshell; so a light touch is required for surface carving. Carving patterns of holes, which I've done on some skulls, doesn't require you to judge the thickness, but still requires care to shape the edges of the holes.

Care:

I used to think that skulls were pretty stable structures, and they are, but they can be damaged by not being stored or handled correctly. I've now seen a number of fangs that are cracked along the sides, from the tip toward the base, and separations at the seams of the skull, such as toward the back of the zygomatic arches.

Zhon, who is a trained taxidermist (and one of a number of taxidermists on DA),  recommends sealing the surface with Super Fish Sealer spray (available from Van Dyke's taxidermy catalog). I'm currently using museum-grade microcrystalline wax for that purpose.

The Bone Room site http://www.boneroom.com/ has a good page on bones:
http://www.boneroom.com/faqs/bones.html

Cast Resin Replicas:

The resin in the replica skulls I've carved is much softer than bone, and not brittle like the clear casting resin I've used for many of my art pieces. It works easily with the same cutters, or wood tools, or hand engraving tools. I like working with it. There are several small companies that make resin skull castings (including werewolf skulls; no, I don't have contact info), but Bone Clones is generally considered the best, and have a huge selection:
http://www.boneclones.com/

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STONE:

Stones have a vast range of hardnesses. One, sent to me by a friend, is so soft that I could carve it with a fingernail (though I used an X-acto knife). I did a carving using it, but regard the result as unsellable because the surface is so fragle. Soapstone is harder, though still soft enough to carve with metal tools, and the soapstone pendant in my gallery was also done with a steel knife. Pipestone, shale, and alabaster are also supposed to be almost as soft as soapstone, but I haven't tried them yet.

Most of my work is done with much harder stones (up to and including quartz), using diamond drills and burrs with my flex-shaft machine. I carve underwater when using diamond, to keep the diamond (and the stone or glass or shell, etc.) from becoming hot and spalling away. Wet cutting also keeps down the stone or shell dust that would otherwise go into the air. I use a cheap stainless steel bowl, and hold what I'm carving just under the surface so I can get a look at it. I have to change the water when it gets too cloudy from the removed material. I dump the bowl outside, because stone dust, like plaster, can clog drains if dumped down them.

I don't know the names of most kinds of rock, and much of what I carve I find at beaches or along hiking trails, but I've learned to judge the hardness of stones fairly well from their weight and appearance, by having carved so many of them. Harder stones carve more slowly, and wear out the diamonds faster, but I often feel that the result is worth it. Too much pressure will wear out the diamonds faster, so patience is required. A faster rotation speed will cut the stone away in less time, so if you can get a high-speed machine, you will need less patience.

AMBER & JET:

Amber is hardened tree-sap, and jet is basically jewelry-grade coal. There is a huge variation in quality, and several types of imitation material are made, but they are mostly carveable with steel dental burrs. The first time I carved amber, I overheated it by using slightly dull burrs, and got something that looked like cotton candy.  I use diamond tools for some of the imitation jet materials, like black glass and vulcanite. (I keep wanting to put together a display board of black materials, with jet, vulcanite, obsidian, commercial black glass, onyx, ebony, charred wood, stained wood, casting resin, acrylic, bakelite, etc.). I consider imitation materials to be legitimate art material, but I label everything as what it is (I have a big piece of fake amber in my display case, which I made myself, using casting resin, as a costume accessory. It is labeled as fake.)

ANTLER & HORN:

Antler is related to bone, and is tough as well as hard. It can be uneven and "gummy" to carve, with the teeth of tools abruptly catching in the material. It works well with steel burrs, files, etc.  Also, antler can overheat from the friction of the cutting tool and discolor, so you need to watch your tool sharpness and the speed and pressure of the cut. The dust is dangerous.

Horn is related to hair, and is gummier than antler. I have not yet gotten to where I can enjoy working with it.
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