The colour finishes we have chosen for our belt buckles and clips have been used for centuries to protect, harden and decorate steel. These colours are created by the skilful application of heat, creating beautiful and enduring finishes.
Colour case Hardening is a heat treatment that hardens and
decorates the buckle. To achieve this the buckle is placed in a crucible
and packed tightly with a carbon rich material, which is then
placed into a furnace and heated. When the buckle is ready
it is quenched in water. The art comes in the colours and patterns
that are created, the exact composition of the packing materials,
temperature and heating duration are a closely guarded secret
and even the slightest variation in process, ambient heat and
quenching water temperature can result in poor to no colours.
After preparation the belt buckle or clip is very gently and evenly heated,
as the surface temperature increases the steel develops a thin layer of
oxidisation changing its colour from straw to brown, to purple and
then blue. Judging the exact point to remove the metal from the heat is
critical. If the steel is heated a moment too long the lay of oxide
becomes to thick, turning the rich purply blue we aim for, pale and
cloudy. If this occurs the belt buckle must be re polished removing
the previous colour and the process repeated.
The prepared belt buckle or clip is immersed in a heated bath of nitrates and sodium that is precisely temperature controlled, the solution corrodes the surface creating a layer of magnetite on the steels surface. Once complete the metal is cleaned to stop any further corrosion and then oiled creating a deep lustrous black.