Ferrules
is the tapered metal tube that holds the brush hair filaments and are
designed for the basic shape and size of the brush. These are made of
different materials - aluminum, nickel, gold, satin, copper lacquered,
chrome, black chrome and nickel-plated. Seamless nickel-plated ferrules
usually appear shinier, with darker tone than aluminum. While
manufacturing, there is a high stress on its dimensional accuracy and
perfect surface finish.
Apart from the normal shapes like conical, cylindrical & fan,
ferrules also come in special shapes and in different sizes such as
curved, ringed, etc. Ferrules made of corrosion-resistant steel, brass,
and nickel, are designed to hold and reinforce the brush knot and
improve the brushes' appearance and add life. Brass, an alloy metal,
makes the strongest ferrules. Though sometimes left plain or with a
clear or gold colored coating, copper and brass ferrules are usually
nickel-plated for appearance and corrosion resistance. Aluminum ferrule
are much weaker but cheaper to produce and appear on lesser quality
brushes.
Quality brushes features a seamless ferrule, regardless of the metal
type. Ferrules with seams tend to pull apart and allow paint, solvents,
and water to accumulate, thereby causing loosening or damage to the
handle. In some brushes, a flexible natural or plastic quill is used in
place of a metal ferrule.
