History

Early Foot Coverings

Shoes As Symbols

Modeling & Creation

Care Your Feet

Outline Of Footwear

Style and Fashion

Footwear Construction

Extra Protection

Glossary

Glossary

Boot Construction Boots are commonly referred to by the method by which the sole is attached to the upper. The most common constructions are welt, cement, stitch down, and direct-attach injection molding.
Cement: Fused to the bottom surface of the insole to reinforce the shoe and support the arch of the wearer. After lasting, the surfaces of both the upper and the outsole are carefully roughed to remove the outer layer of material. After roughing, cement is applied to both surfaces. Immediately before the upper and outsole are put together in the outsole attaching machine, the dry cement on the outsole must be "activated" that is, brought into the proper condition for bonding. The cemented outsole and upper are placed into an activating device where the cement film is properly conditioned by heat to the required state for secure bonding to the cemented upper. The outsole and upper are taken from the activator, quickly assembled by hand to the lasted upper, and promptly placed into the sole attaching machine. This machine immediately exerts adequate pressure on the shoe, bonding the outsole to the upper.

Stitchdown: In stitchdown construction, shoes may be single-sole, two-sole, or three-sole. Common to all is the basic construction principle of flanging the upper out over the top of the sole extension and fastening the sole to the upper by stitching through this outflanged margin. It is the only construction where the lasting margin is turned outward.

Direct Attach: In injection molding, thermoplastic materials are heated and liquefied before entering the mold. The mold is not heated, so that the heated liquid cools and sets, or returns to a solid form in the shape of the mold. Sometimes chemical accelerators are used with certain materials, such as polyurethane and are mixed in the machine head and rapidly injected into the mold because of the speed of reaction. Many of these materials do not require pre-heating because the chemical reaction produces its own heat. The injection molding process is used for both flat lasted and string lasted footwear.

Calendaring A process of passing material between one or more rollers (calendars) under controlled heat and pressure.
Outsole Types Outsoles are generally classified by what materials they are made of, and what shape they are in relation to how they will appear on the finished product. Outsole shapes are generally divided into the following three categories.
Blocker: sole is oversized, and trimmed in the making process to fit to the bottom. One blocker size can usually be used for 4 whole sizes of finished product.

Net Fit: sole is made to fit exactly to the bottom of the boot. There is one size of bottom for every size, although usually half sizes and multiple widths of a size can be accommodated.

Direct Attach: the sole is molded directly to the upper, as described in the construction section.

Outsole Materials The following are five different materials most commonly used for making outsoles.
Leather: natural product made from animal hides.

Rubber: natural product made from plant by-products.

PVC: by-product of mineral oil.

Polyurethane: product of the reaction of two materials, isocyanate and polyol.

EVA: plastic product produced by combining ethylene and acetate, sometimes blended with rubber to increase abrasion resistance.

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