Leather Finishing MethodsDan Naegle, Campbell - Randall Machinery

Once a hide finishes the tanning process, the leather can be manipulated for a variety of looks and textures. At the tannery the leather undergoes a series of wet operations for coloring and oiling. After the hide dries and it is in the “naked state”, it can be mechani-cally conditioned for different look or feel. Some of these same techniques can be used at your work bench. Beyond dying and oiling the leather, we’ll take a look at physical conditioning methods to give plain old leather a new and different look.

Staking:Staking is a method of massaging a hide to make the leather more pliable. In years past, a operator would hold a skin against a bar while a staking machine would grab the hide with rubber rollers and blunt blades to pull and flex the skin. This stretching makes the leather softer and more pliable. Tanneries refer to this characteristic as tem-per.

Buffing: Buffing is a light sanding operation to either side of the hide. Buff-ing the underside will improve the nap and produce a velvety texture known as suede, while buffing the grain surface will smooth out some natural imperfections such as scratches, scars, etc.

Full grain leather has nothing removed except the hair, and possesses the original grain of the animal. This is the strongest portion of the

hide. Buffing the grain with a emery wheel will produce an altered grain known as snuffed top grain, hand buff, nubuck leather, or corrected top grain. This is typically the same as a fulltop grain leather, but the hide is lightly sanded to remove only the top of the hair follicles. A tannery will use a machine to buff approximately 1/64 in or 1oz in thickness from the grain. This should leave a portion of the grain on the entire hide and results in a cleaner surface.

Modern tanneries use large machines with many thumb-size pins that oscillate and pound the leather as it travels along a conveyor. This same technique can be applied by rolling, stretching, or massaging a stiff piece of leather at the bench.Source: Cudahy Tanning, division of Prime Tanning

Boarding:

Boarding leather accentuates grain or pro-duces additional wrinkles by folding the grain side and working the leather back and forth.

A boarding machine consists of 2 rollers with a blunt blade that gets pushed be-tween the roll-ers. The skin travels around the blade and is flexed tightly due to the nipping action of the rollers. Ag-gressive boarding can create a wrinkled or distressed look to the leather.

At the bench, hand boarding is done with a curved cork board attached to the worker’s arm. The worker rolls the board over the folded skin until the desired look is achieved.

Hand slickering is used on delicate leath-ers and soft leathers, where the harsher ac-tion of the staking or boarding machines would damage or mark the sur-face of the leather. The leather is wrapped around the hand slicker which is pushed along the surface of a table.

Plating (Embossing):

One of the final con-ditioning processes is embossing the hide with heat and pressure to create a chosen grain in the surface of the hide. A unique design can be used or an imita-

tion of full grain. Sometimes leathers are embossed to make them appear to be an-other leather, such as embossing an alliga-tor or ostrich pattern into cowhide.

It requires hundreds of tons of pressure to emboss a full hide. Some shops my find a small scale plate embossing press use-full for cut pieces, especially for emboss-ing saddle parts or hand bag leathers. If a plate embosser is not in the budget, a heavy duty rotary embosser can do the trick. Some models, like the Randall R32, will accept rolls dies up to 7 inches wide to emboss an imitation grain on straps or small leather pieces.

Glazing:

On of the oldest finishing methods, glazing is a process of polishing the grain surface under heavy pressure with a roller of ag-ate, glass or steel. A protein additive, albu-min – derived from egg whites, is applied to the surface of the leather and allowed to dry. The dried leather is then placed on a glazing jack, a machine equipped with a solid roller that quickly strokes of the sur-face of the leather by means of reciprocat-ing arm.

The pressure and the number of strokes can be controlled by the operator to achieve the desired degree of shine, thus enhancing color tones and a finish in differ-ent areas of the skin as needed. The fric-tion of the glass rubbing across the surface creates heat and hardens the finish, while the quick action produces a mirror-like surface. The heat of the glazing jack also causes darkening of the colors and raising of some of the oils in the leather. The re-

Brushing:

Brushing or polishing machines can be used to remove surface defects, polish finished products, or brushing effects for vintage and distressed looks. Horse hair brushes

are great for polishing a hide surface and can be used with polishes or waxes. Felt wheels do an excellent job without leaving or strings behind. You can also use cloth or yarn mops. For a different look, brush with special abrasive or soft wire wheel to age the leather. This technique is popular for fashion accessories. Don’t be afraid to experiment a little. You even might be able to turn that sow’s ear into a silk purse!

sulting finish produces a natural depth and beauty to the leather.

Traditional glazing can be costly, as it may be necessary to apply as many as six dif-ferent coats involving several glazings, platings, staking and brushing operations to bring the desired characteristics. It is difficult to reproduce glazed finishes with a modern mechanized processes. Glazing is confined to the more expensive types of leathers, such as reptile, kid, and high-grade calf. Glazed finishes are also known as Sleeked (done by hand with a copper tool), and Glassing (done by hand with a lump of glass used as the glazing tool). A glazing jack is a machine that duplicates the hand process, and can be used to do several types of finishes, such as a pumice rod for buffing, and boarding and graining operation.