Knuckle Bone preparation 1996

Aim to obtain 6000 clean knuckle bones to repair Knuckle bone Arbour, Castle Ashby. I purchased quantities of sheep feet from a Halal slaughterhouse complete with skin and hoof. These feet (first 250mm) were put into sealed plastic drums for my collection. Fifteen drums contained 6000 feet. I later discovered that only the front feet of the sheep contained the classic knuckle bone used for flooring. I doubled the order and had approximately 2 tons of material to convert. The plastic drums, now with lids of 3/4-inch wire netting were left in a wood. The wire would allow flies but deny access to dogs, foxes etc. The flies were attracted and some drums erupted with maggots, some did not I do not know the reason why. Some drums were stood up and rain allowed to fall in, some were laid down so liquids did not collect. The maggots attracted several species of beetles and other predators.

After four months the flesh had broken down but not disappeared, the wool and hoof and remains of sinew and cartilage formed a type of felt mat which covered the bones and, I feel, reduced the rate of breakdown. Putrefaction seemed to form a pickle. At this point I found many of the knuckle bones became detached from the cannon bone. This might have been caused due to part of the process. Had the bones not become detached at this point, perhaps they would become detached when laid in the floor.

The bones were separated and put into the drums with 500 grams of caustic soda. This did breakdown some of the material attached to the bone and after a few days this material was scraped away and the bones rinsed. Some of the bones were yellow with fat, some were almost black with slime but when exposed to sunlight all whitened up. The bones needed for the restoration were taken to Castle Ashby, the remainder were left in the drums.

This year, four years later, the drums were emptied. The bones had mostly separated but the felt type material originating from wool, hoof etc. remained, as did the smell. At this point the material was, if can be measured, on a par with farmyard manure. After another ten weeks exposed to the elements the knuckle bones are in a position to be picked out and counted.

Experiment to convert sheep feet to usable knuckle bones for flooring.
After talks with the Natural History Museum a sodium perborate method was recommended for the cleaning of animal bones.

Fifty sheep feet were collected from an abattoir the day the animals had been slaughtered. They had an average weight of 200 grams and a length of 200mm. Using a mechanical saw the knuckle bone was cut away. Care had to be taken not to damage the bone when cutting of the meta carples. It was found that following up with a knife was needed to remove the remaining skin and attached meta carples. ( Approx. 2 minutes per bone) These cleaned bones (40mm length 50 grams) were put into the bottom of a plastic bucket and covered with 100 grams of sodium perborate. Boiling water was pored over the mixture and the bucket was covered with a plastic bag. When the water was pored, bubbles rose through the liquid for a few minutes, I would not describe this as a violent reaction. Observations of the bones taken after a few hours, a day, and a few days did not show much change. The flesh became whitish in colour as might be expected if immersed in water. No perceivable change was observed over the next few weeks. Some of the buckets were drained of liquid, some were left to evaporate. Crystals of sodium perborate reappeared. The liquid in the buckets did become greasy. The common factor was that there was no noticeable smell of rotting flesh. When very close the slight smell could be described as lamby.

The Sodium Perborate method will reduce smell but will not magically remove the flesh from the bone. Maciation with water will eventually remove the flesh, this would take more time and man-hours than anticipated and other ways of removing the flesh from the bone need to be looked at to reduce the cost per bone.

Terracotta Knuckle Bones
A company who specialise in the restoration of 18th century white terracotta has been approached to make artificial knuckle bones. Moulds will be taken from bones of various sizes to produce individual terracotta bones. The texture and colour are similar the life span should be greater than a sheep produced bone.