Technical Information:CUIR BOUILLI: BACKGROUND INFORMATION
Cuir Bouilli (boiled leather) is an ancient technique for forming and hardening leather. However, the details of the process are almost entirely a matter or conjecture. It has become a general term used to describe two very different bodies of work: the sometimes crude and serviceable English bottles, blackjacks, and bombards; and the highly decorated and sophisticated European (principally Italian) caskets, missal and scroll cases, as well as powder flasks and parade shields. Both are formed and hardened and in each case there is heat involved in the hardening process; however, the way heat is used is very different in each case. There is also leather armour. Little of it survives but there are abundant references to it being made of cuir bouilli. The limited material still in existence suggests both hardening processes were used depending on the time, local and function of the armour.
The Italian work which dates from the 12th century to the mid 16th century (when it seems to disappear) is highly decorated and by the 16th century involved complex three dimensional forms of unequaled technical difficulty. It was most likely hardened by impregnating it with hot pine resin or perhaps (but less likely) a high melting point fat such as stearate.
The English vessels were produced until the first quarter of the 19th century with the earliest surviving examples dating from about the 14th century, but with references to them dating from much earlier. Despite what the name suggested, boiling the leather was rejected as unworkable by the late John Waterer the influential writer on the history of leather work and the founder of the Museum of Leathercraft in England. He thought the work had been baked but not taken to shrinkage temperature.
It was the discrepancy between the literal meaning of the term cuir bouilli and the process Waterer believed it described that initially attracted my attention. It simply made no sense that a term so apparently descriptive would have no relation to the process. My work makes it clear that boiling is a viable process, however my investigations are not exercises in historical reconstruction. The forms, the construction methods, and often the function of the work I do have relatively little in common with their historical antecedents. What is clear from examining these historical objects is that they have been taken to shrinkage temperature. It is possible that some of the objects could have been hardened by using a boiling water process, but it is almost certain that some objects were hardened by baking them and it is probable that most of the objects we have left to examine were hardened by baking . Water hardening processes very likely date from pre-historical times (an iron age shield was discovered in Ireland in 1908). Given this lengthy history it seems probable that boiling was used at some time and that cuir bouilli was the term coined to describe it.