Historically, all tanning was done using chemicals derived from plants, such as extracts from the barks of certain types of trees, until the nineteenth century when chrome salts were introduced.
There are two types of leather – full grain and top grain. Full grain leather is leather that has not been tampered with after removing it from the animal – the hair is removed and the grain or epidermis is left on. Top grain leather is worked with to cover up any scars or blemishes on the skin and is usually sanded and sprayed.
The process of tanning varies according to the intended use of the leather. However, generally in the preparation for tanning, larger animal hides are divided and cut according to body areas, while smaller animals (e.g. calf, goat, pig and reptiles) are left as one piece. Firstly the hair must be removed from the skin. The hides and skins are in water to be washed and rehydrated, with lime liquors used to loosen the hair and plump the hide. The hair that has been removed is sold on to plasterers or felt manufactures. The hides and skins are naturally uneven and of different thicknesses. Therefore, in order to even them out they are run through a plotting machine. Thickness throughout a hide differs, hence why leathers are shown to have different thicknesses on their labelling.
The tanning process consists of putting hides in weak solutions of tannic acids which gradually increase in strength. The tanning operation varies in time from three weeks to three months, dependent on the type of hide being tanned and the thickness of it. The leather is then dried in such a way that the leather does not diffuse into ‘grain’ or the ‘flesh’ using oils applied to wet leather which form a film to arrest this diffusion. While still wet, the leather is ‘set out’ removing creases and ‘rolled on’ to help make the characteristic smooth surface of leather. The leather is thoroughly dried out and ‘rolled off’ on very heavy pressure rollers which gives the polish to the finished leather.
Mimosa bark tanning: There are some crafts people now using Mimosa bark for tanning, which is grown specifically for the purpose in South Africa.
Peat tanning: Peter Ananin at the Woodland Tannery has been exploring the historic process of peat tanning, which disappeared from the UK in around 1880.
Different people do different parts of the job. There are crossovers where they do other people’s jobs, but no one person does it all. Tanners would be working in the tanyard, limeyard men working in the limeyard, curriers would be staining and dressing leather and then those in the machine shop who would be splitting and shaving. Some people might do more than one of those.
Dickens Brothers Ltd has closed in recent years
In September 2018 we learned that Claytons of Chesterfield had gone into administration with an immediate loss of 14 jobs, with 11 remaining to wind up the business. The firm had been going for 178 years.
In December 2018 we learned that ex-employees and interested parties have been working on a rescue plan with a view to forming a new company and have been successful in acquiring all of the assets and rights to trading at the premises of the previous business. The new company name is Spire Leather Company Limited, and is now operating from the Clayton Street tannery.
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