Horn, antlers and bones
There is evidence that our ancestors have been making tools, weapons and implements from antlers and animal bones since the Early Stone Age.
Origin, properties and use
The material, which is very hard but can still be worked with flint, was used for blades, composite bows, hammers, sewing needles, spearheads, fishhooks, bows and fittings as well as for jewellery, inlays, cases and wind instruments. Due to the lack of wood, antler and bone material was the most important material in the polar cultural area for thousands of years to ensure survival under arctic conditions. To this day, Sami knife handles and sheaths are preferably made from reindeer antlers.
Due to its structural similarity, bone material is now a popular substitute for (species-protected) ivory and is used in this context for restoration, inlay work and components for musical instruments, e.g. keyboards.
Antlers
In contrast to horn, antlers consist of bone substance. Chemically, it is a matrix of approx. 60% mineral salts (mainly calcium phosphate), interspersed with collagen (fibre-like protein). The calcium phosphate gives the antlers hardness, the collagen provides elasticity.
Antlers are obtained from deer, roe deer, elk or reindeer (zoologically cervids), either as shedding poles (antlers grow back annually and are shed in late autumn) or as a by-product of hunted animals. Only in the case of reindeer do females also produce antlers, but these are rarely utilised due to their smaller size and lower hardness.
The canes are solid at the ends and blades as well as in the area of the rose canes and otherwise porous at the core. The hardness increases in the course of growth, the best material is provided by fully formed autumn antlers or shedding sticks. The brownish discolouration is caused by blood from the detaching basal skin at the end of antler formation and plant juices that penetrate the bone substance during the beating of the antlers in bushes and trees. Due to longer periods in the ground, antlers and bones can show colour changes, brown tones and marbling, which are popular with knife makers. However, the time spent in the ground is usually accompanied by embrittlement of the material, which may therefore need to be chemically stabilised before processing.
Animals that live freely, are not fed and grow up under rather harsh conditions develop firmer and more finely structured antlers. This is particularly important when the material is used for scrimshaw engravings, carvings, knife handle scales, etc.
Bone
Bone material is mainly obtained from the thigh bones of cattle, horses, buffalo, camels and giraffes. The bone marrow is removed and the bone is sterilised by boiling for a short time. A little washing powder (1/2 cup / 5 litres) can be added during cooking to remove the fat. Boiling for too long makes bone and antler material brittle, as the collagen is dissolved out.
A weak vinegar solution can also be used for disinfection. However, caution is also advised here, as acids dissolve the calcium phosphate after prolonged exposure and thus soften the material.
Processing
Mechanical processing
Antler and bone material is hard and brittle and therefore not easy to cut, but it is easy to grind and polish.
Fine dust and harmful vapours may be produced when heated. Wear a dust mask and vacuum!
Fresh antler and bone material can be cut with a robust toothed Japanese saw (e.g. No. 712610). For finer cuts on hard, seasoned material, the use of hacksaws (e.g. No. 712715) is recommended. Caution is advised when using band or circular saws. There is a risk of overheating and jamming due to softening of the material! Saw at low speed and cool with water. Allow thicker cuts to dry slowly and in cool conditions to avoid cracks.
- Shaping antlers
Fine metal or diamond files and abrasives are used for shaping. The surface is finished with abrasive cloth and then Micro Mesh polishing pads (no. 705420), with the addition of water up to a high-gloss polish. Alternatively, traditional polishing agents such as pumice powder (no. 810050) and tripel, bound with water, can be used on a cotton cloth or with a buffing disc. Oil should only be used as a lubricant or polishing agent after prior testing, as it may cause yellowing of the material. Avoid coloured polishing pastes and other colouring agents (metal dust etc.), as these can hardly be removed from the surface. - Antlers as material for scrimshaw and engraving techniques
For scrimshaw and engraving techniques, the usual tools used in metalworking are used, e.g. etching needles. - Antlers as turning material
Turning with a graver-shaped, scraping tool is also possible at low speed.
Plastic moulding (bending)
Bone and horn material can be made pliable by prolonged soaking or boiling in highly diluted hydrochloric acid or acetic acid. However, the process is not reversible! The parts therefore remain rubbery and elastic even after drying.
Bonding
As with all bonded joints, it is advantageous to roughen the surfaces of the two bonding partners, e.g. with 60 grit sandpaper. The surfaces must be thoroughly degreased before bonding. You can use a solvent such as acetone, but it is better to clean the surface with a scouring agent and water (binds the grease as opposed to the solvent).
The traditional glue for these natural materials is glutin glue, which is obtained from skin or bone material. It is available both as hot glue granules (No. 450140) and as liquid instant glue (No. 450368). It hardens transparently and has high strength for all organic adhesive pairings (horn, bone, wood, tendons, etc.), but is not waterproof.
- Adhesive for bone/antler on metal
Epoxy resin adhesive (no. 450382) has proven to be ideal for bone/antler/metal pairings (knife handles). It is transparent and gap-filling and is therefore also suitable for porous surfaces. Mixed with fine sanding dust (grit min. 220), slow-setting epoxy is also well suited as a pore filler or for concealing small cracks or surface defects. - Adhesive for bone/antler on oily wood
Very reliable bonds, even with oily woods, are achieved with a resorcinol resin adhesive, which, however, does not cure transparently. - Adhesive for bone on bone
Cyanoacrylate adhesive (superglue) can be used for bonding smaller bone parts to each other; it is also suitable for correcting small surface defects.
Bleaching, colouring, surface
If desired, bone/antler material can be bleached. This is particularly recommended for plates that are used to imitate ivory or are subsequently coloured.
The dry bones are treated with hydrogen peroxide (brushed or sprinkled with cotton wool).
Then rinse the piece in lukewarm water and allow it to dry slowly.
When doing this, make sure that no hydrogen gets onto the antlers or horns.
Cover the container, make intermediate checks and use rubber gloves!
Bone material can be coloured by prolonged immersion in spirit-soluble stain; natural dyes such as alkanna root or black tea are also suitable.
To prevent polished bone material from drying out and becoming dull, it can either be polished regularly with a non-resinous oil (e.g. camellia oil) or wax, or a thin shellac sealant (DVD no. 713736) can be applied. This preserves or even enhances the lustre, makes the material insensitive to hand perspiration and prevents embrittlement. However, shellac is sensitive to solvents and cleaning agents.
Be careful with your own hands! Human skin also reacts very sensitively to hydrogen. Hydrogen peroxide must therefore always be kept closed, well labelled and safely stored.
Caution - risk of chemical burns! Use only in a well-ventilated area, no guarantee or liability!
Mechanical processing
Bone and antler material that has been exposed to erosion over many years often develops a marvellous patina or strikingly textured surface, which is much sought after by knife makers. Unfortunately, this fossilised material is usually brittle and fragile. Stabilisation with synthetic resin can provide a remedy. Either low-viscosity acrylic resin or epoxy resin, which hardens anaerobically, is used for this purpose. The latter in particular produces a very stable and wear-resistant bond that is completely water and largely acid-resistant.
In order to fully penetrate the material, a vacuum is required. To do this, the container with the part inserted in the resin must be placed in a vacuum chamber and held there until no more bubbles appear. You can create a temporary vacuum chamber yourself using a water jet pump and a pressure-resistant glass bell jar. In the professional sector, a so-called "exiskator" is used for this purpose.
Note: The PEG (polyethylene glycol) process commonly used for wood cannot be used for fossilised, thoroughly dried bone material, as it is based on the replacement of stored water with PEG.
Care
Bone and antler materials are not only durable, they even gain patina through use if a few care instructions are followed:
- Do not expose to dry heat (spotlights, sun) for too long
- Do not store too dry
- Never put in the dishwasher, do not put in water or boiling food for too long
- Do not clean with solvent-based household cleaners or abrasive cleaners. Rinse with warm water and light soapy water is sufficient
- Do not apply high bending loads
- Occasionally rub with camellia oil or Ballistol and polish again
Note: The PEG (polyethylene glycol) process commonly used for wood cannot be used for fossilised, thoroughly dried bone material, as it is based on the replacement of stored water with PEG.
