Vache Sole Leather
As its name implies, vache sole leather is a Continental product, being made chiefly in France, Belgium, and Germany. The raw material consists of light and medium cow hides. The details of working are somewhat similar to those used in tanning English sole leather, the main difference being that the hides are suspended in the lime liquors instead of throwing them in flat. The system of tannage is not so varied as the English, since the materials used generally consist of oak and pine barks, myrobalans, quebracho and oak extracts; and the finishing materials are of quite another character. The Continental tanners generally use the Réaumur thermometer, while the Beaumé hydrometer is used to determine the density of the tan liquors in place of the English barkometer (Fig. [24]). One degree Beaumé is equal to 6.9° barkometer.
Vache leather is more pliable than English sole leather, but the addition of valonia extract towards the end of the tanning process would greatly increase its firmness.
The finish is applied to the flesh side of the leather, and a typical recipe consists of a size such as Irish moss or Tragasol (1 part), flour (20 parts), china clay (20 parts), and pure gambier (2 parts) in 200 parts of water. The size is dissolved and cooled, and the other ingredients are then added.