In order to have a good pair of high quality men's leather, skilled craftmen have to do a lot of complicated work. A pair of men's shoes go through hundreds of steps to create final products as men are using today. However, the tanning process has only three basic stages: preparation, tanning, correcting and finishing.

1. Preparation

Preparation is the first step in the tanning process, in which the purpose is to remove the excession to form a link between tanning agent and collagen fibers during tanning. These includes the connective tissue, epidermis and the substances that can be easily destroyed by bacteria. All pieces of leather must be carefully classified according to type, size, volume and specific properties... for storage and processing standards for each type.

The steps involved in preparation may vary, depending on the material, the method of preservation and the using purposes of the final product. Includes: moisturizing, hair removing, soaking, scouring, bleaching, softening by acidification.

Moisturizing

In the tanning process, the purpose of moisturizing is to restore the amount of water that is lost due to the preservation process, which means that the texture of the skin is restored as it was at the beginning. Skin preserved by drying is more difficult to moisturize than that by salt. So, moisturizing is dependent mainly on the sense, good result is when the hair is as soft as it is fresh.

Long recovery time will cause bacteria to grow and cause skin damage because a part of collagen in the skin would be destroyed, craftmen should pay attention in this period. Temperature of 26-27 degrees Celsius is the best to stop bacteria.

Hair removal, soaking

The purpose of this step is to remove the hair, epidermis and the fat layer under the skin. This stage is quite complex, requires strict control of the use of chemicals, water, temperature and time. The chemicals works to destroy the pores and epidermis on the skin and promote skin renewal. The effect of sunfuanatri (pH 12:13) plays an important role in the removal of feathers and hair.

Today, with modern tanning techniques, liming is carried out in foulons at a speed of 3-4 rpm, from 12-18 hours and craftmen need to roll the mix in 10 minutes each hour so that the solution is penetrated the skin. Because hard skin cleanser will form CaCO3 on the surface of skin and make the final product poor-qualified, when washing, 0.5% of amount of lime is required to avoid skin deterioration. This process is done in foulons from 12h - 24h, the amount of water and the amount of chemicals must be respective to amount of skin. 

Tearing 

This stage is done by machine for distributed skin thickness.

Lime removal, softening

After hair removal, the chemicals should be removed, otherwise they will affect the quality of the leather. These steps are usually carried out in foulons, the softening process is carried out after the lime and chemicals in the skin has removed in order to increase the quality of the leather.

The process of softening is to give the skin a smooth, all-embracing, and hated surface. Softening agents will affect unstructured collagen such as elastic fibers that increase softness, elasticity of the kidney, this is significant for chrome leather - items that make belts, shoes, leather briefcases, leather bags, gloves. It does not make sense for hard leather types like shoe soles, leather for industrial use.

In fact, the softening process is carried out in the same foulons used for bleaching and in the same tank of the scrubbing step. The temperature and time factor are very important for the softening process, the optimum is 370C, Because this temperature is suitable for yeast activity, the pH is also important, the optimum pH is 8.3. Long softening time will reduce the tensile strength of the skin. Check the softening process by folding the skin and squeezing it to allow air bubbles to pass through.

2. Tanning

Tanning is the process by which raw skin is transformed into a leather with its optimum properties such as high temperature resistance, no rotting when exposed to water and other environments and destructive resistance of the microorganism. At present, different neutralizing agents are used, their alkaline uptake increases gradually, such as Mentrigan MOG, Dolomite Mineral. Next, we need to check the penetration of acidification, temperature test and pH.

3. Correcting and finishing

The skin after tanninge content has high moisture of 60 - 65%, no flexibility, rough surface and high water absorption. So, it is necessary to go through the correction process to make final products which get satisfaction from users. Different types of skin create different types of leather.

It is also important for men to have leather shoes. After the tanning process, we will have a great pair of shoes.