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Vulcanized Shoe Construction vs Cold Cement Process
Wade Motawi The Shoe Dog
In this blog post, we will compare vulcanized shoe construction with cold cement shoe construction. Vulcanized construction, an older method, was replaced by cold cement construction in the 1980s. However, vulcanized shoes experienced a resurgence in 2010.
Cold cement construction allows the use of lightweight plastic, foam, and mesh materials due to lower bonding temperatures. Modern high-performance athletic shoes, including those made by Nike, are produced using the cold cement process. On the other hand, vulcanized shoe construction represents the classic method of making sneakers, such as Converse All-Stars and Vans skate shoes. However, the high temperatures required for vulcanization limit the material options, with canvas and suede leather being common choices.
Cold Cement Shoe Assembly Process:
In cold cement construction, the shoe upper can be combined with a Strobel bottom, resulting in a lighter and more flexible shoe. The upper is steamed to soften the materials, and a last is inserted and tightened. A second lasting machine secures the last inside the upper, and temporary shoelaces are tightened. The upper is cooled to shrink it to the last, and a plastic or fabric part may be installed on top of the tongue to protect it during lasting. Meanwhile, the sole unit, consisting of a rubber sheet sole and EVA foam cushioning component, is prepared separately through a process called stock fitting.
Shoe Sole Cementing:
After the upper and outsole are ready, a primer and cement coating are applied to both. Skilled workers align the upper and outsole, placing the shoe in a hydraulic press for three pressing operations: vertical, toe and heel, and side press. The shoe is then cooled to set the glue, and a de-lasting machine removes the last without wrinkling the upper. The footbed, either molded EVA with a fabric cover or flat, sheet-cut foam, is inserted. The completed sneaker undergoes final quality control inspection, cleaning, packing, and shipping.
Vulcanized Shoe Construction:
Vulcanized shoe making, as seen in Converse All Stars and other Converse classics, requires a metal last due to the heating process.
Board Lasting Operations:
The lasting board is lightly cemented to the metal last, providing stiffness. The toe lasting machine pulls the upper onto the last, bonding them together. Once the shoe heel and waist are lasted, the upper is ready for the outsole. The vulcanized outsole assembly process is similar to cold cement construction, with primer and cement coating applied to the upper and rubber sole parts. The rubber bottom and cushioning wedge are then bonded to the upper. The foxing tape covers the rubber outsole and overlaps onto the upper for a solid bond. Additional tape is added, and a rear logo covers the joining seam. Excess rubber is removed, and the sole is pressed to ensure proper fitting.
The Vulcanizing Oven:
The shoe, with the last inside, is placed in a vulcanizing oven for several hours. This process fuses the uncured foxing tape and sole unit together. After cooling, the last is removed, the footbed is inserted, and the laces are attached. The shoes undergo final inspection, cleaning, and packing.
To further expand your knowledge on shoe construction methods, including cold cement and vulcanized constructions, as well as other popular techniques, you can refer to the comprehensive guide "How Shoes are Made." Chapter 12 of the book provides detailed insights into shoe construction, terminology, sneaker construction, and more. Whether you prefer a softcover edition or a PDF download, you can access "How Shoes are Made" for immediate delivery and start exploring this fascinating subject today!
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