1. Leather material selection
There are so many leather materials that can be used to make watch straps, such as crocodile leather, lizard leather, ostrich leather, shark leather, cowhide, corroded leather, etc.
Watch strap leather is the best and most luxurious. The leather feel and quality of the leather are nothing to say. Small items like watch straps are especially imported American crocodiles.
American alligators are generally smaller in size, so the leather size is also smaller than other species.
Because it is not as aggressive as other crocodiles, generally speaking, the leather will have fewer scars. The square texture on the abdomen and the fine round texture on the side abdomen have a clear distinction. There is no feeling of excess, so it is not suitable for making large leather goods. Especially suitable for making watch straps.
This crocodile leather has no brown eyes at all, the leather is firm and delicate, the pattern is three-dimensional, and it has more beautiful texture details than other crocodiles. The American alligator has a wider tail than all crocodiles. The bamboo-shaped texture on the belly and tail is used to make the table. The best choice for belts. MECANO only chooses the best position of the abdomen when making watch straps, and other leftover materials are not made.
Of course there are other types of crocodile leather, so I won’t repeat them here.
The texture of shark leather is very unique, showing a vertical shrinkage texture, which is very three-dimensional, and has good ductility and strength. Unlike most fish leather, shark leather is very flat and has a larger area. Unique texture And the texture is also very good, and it is also very suitable for making watch straps.
Compared with the American crocodile, the grade is slightly lower, and there is no American crocodile.
Lizard leather is also a very high-end leather material, and its texture is also very special. This kind of leather is softer and lighter. Compared with crocodile leather, it is not so domineering. Now there are many watches like Emperor Camel, Breitling, etc. who choose this kind of leather as watch straps.
Ostrich leather can also be regarded as one of the more precious leathers. It is soft, light, strong, breathable, and wear-resistant. Ostrich leather has a natural pattern formed by pores and has a special natural feather hole dot pattern, which is good Breathable, it is very comfortable leather.
The biggest feature of the strap made of cowhide is that it is cheap and durable; the leather material of cowhide is also divided into many kinds, the best grade is calf leather, which is made of calf leather within 6 months after birth. Leather, so it feels exceptionally soft, the fabric has small textures, and the straps made are also very attractive and beautiful.
However, compared to the high-end fabric of American crocodile, the leather feel and texture are much worse, so most of the cowhide fabrics are used on the low-end straps.
Horse hip leather
The horse hip is the Cordovan layer on the horse’s buttocks. It is the inner layer of the horse’s hip leather. After polishing, it has the current delicate and lacquered effect. Only one-eighth of the horse’s hip. Very rare, it is the most sought after leather in high-level customization. Corridor leather is also more suitable for making a single-layer strap than any leather.
The more famous ones are the Japanese New Jubilee cordovan leather, the Japanese Ogawa cordovan leather, and the American Holvin; generally, this type of leather is used for retro-type watch straps. High-end formal wear watches will not choose this type of leather material.
2. Design and pattern making
Different brands, different styles, and different sizes of watches require different strap sizes. In order to match, detailed designs must be made on the computer and patterned before actual production.
The pattern-making is divided into two types, one is the manual pattern making, which uses a carving knife to carve out the template of the strap, which is suitable for small batch customization. The disadvantage is that the production speed is slow and the process is complicated.
The other is the die cut, which is made according to the previous design data, which is suitable for mass production.
In the early days, consumers pursued “manual”, and the deeper level was to pursue ‘more refined’ products, because the early large-scale industries were difficult to achieve refinement.
Consumers basically want more sophisticated products, and the use of the die cut perfectly meets this requirement. Including the small pieces of leather produced by Hermès, they are all processed by die cut. If a person tells you that his watch strap product does not use the die cut, there is only one situation, that is, the order is too small. Because the cost of developing die cut is much higher than using a one-time manual pattern making, and the data of each strap is different.
The elbow strap suitable for formal watch is cut with a customized high-precision die cut, and the lines at the interval are smooth.
3. Cutting leather
In order to make the two parts of a watch band have a better visual effect, we will “compare the patterns” when cutting the material, and try to avoid the scars left by the animals during the growth period.
The reason why a good leather strap is relatively expensive is that there are too many waste leather materials generated when the material is opened, and the utilization rate is low. Those with big scars, messy patterns, and holes must be thrown away.
4. Bottom leather, core material
The genuine leather is on the front of the strap and is called “face leather”. The one on the back of the strap is called the “bottom leather.” There are two common bottom leathers, one is cowhide (left) and the other is sweat-proof leather (right). The cowhide can absorb sweat, while the anti-sweat watch does not. Both have advantages and disadvantages. The cowhide tends to smell after absorbing the sweat of the wrist, but it is comfortable to wear for a long time. Anti-sweat leather does not absorb sweat for a short time, but the surface coating may still be corroded by sweat, making it uncomfortable to wear.
There is a ‘core material’ in the middle of the top and bottom leather, the function of the core material is to make the strap more three-dimensional and full.
Brand new straps are generally stiff, because the core fiber inside is still in a flat state. After being worn for a long time, the core material will deform according to the wearer’s wrist to fit the wrist for better wearing comfort.
In addition to the core material used for filling, some leather straps will have a “break-proof” design. For example, the crocodile leather strap is not uniform because of the fiber composition of the dermis. At the junction of the scales, the fiber is relatively sparse (the dark red part of the above picture is the junction of the scales, the fiber is sparse, the dye is easy to invade, and the color is relatively darker), under certain circumstances Fracture will occur. At the same time, the part connecting the buckle and the watch head is repeatedly pulled every day, and it may break. Therefore, a good crocodile leather strap will have strong fiber imported from Germany on the inside. This fiber is only 0.15 mm thick, but it can resist huge horizontal and vertical tension. In the case of ensuring the beauty, the protection strap will not be completely broken.
5. Bonding, heating and shaping
After the dough, bottom, core, and strong fibers are prepared, they are glued together. In order to create a full, three-dimensional appearance, some watch straps need to be placed in a special mold of the corresponding size. The mold is made of stainless steel and brass with thermal conductivity.
The strap and the mold will be placed on a constantly heated metal plate and held for a period of time to allow the glue to penetrate into the fiber layer and shape it.
More special straps even have to be heated on both sides, and the temperature on the front and back is different. The specific temperature has to be adjusted according to the glue used. The warmed watchband will bond better than natural air-dried glue, and the watchband will be stronger.
The bonded watchband needs to be sutured to improve the firmness and aesthetics.
For making watchbands, commonly used stitching brands include French Fil Au Chinois (Hermes also uses this brand’s thread), French Coats (the world’s largest stitcher), and Japanese hand-stitched twine.
This ‘saddle stitch’ method is matched with the holes processed by the “European oblique and flat cut”, and the finished product will show a very beautiful ‘wave pattern’.
The ‘saddle stitch’ is not only durable, but also beautiful. But its shortcomings are also obvious, that is, time-consuming production and high sewing technology requirements. Every time the needle thread enters the hole, the angle must be the same, and the force applied when pulling it out must also be the same, otherwise it will not become a regular wave pattern.
7. Apply side oil
Although the leather is cut with a knife, the edges still have more or less burrs. Therefore, in order to be tidy and to increase water resistance, the cut edges of the strap must be wrapped.
It is commonly used to apply side oil, which will gradually condense into an elastic solid at room temperature to protect the strap.
After finishing the edging oil, let it dry naturally, and then finely sand it with sandpaper to make the edging oil surface smooth and clean. In order to achieve the best results, the two processes of upper oiling and polishing must be performed at least three times.
8. Drill holes
The 7 clasp holes, if punched one by one, it is easy to slant off. But we use special tools to fix it, which can produce good results at one time.
In addition, there are also special molds for the punching of the pin buckle tongue position, and different designs for different width watch bands.
The last watch strap is like this. Our factory will mark the logo according to the order requirements to complete the production of the leather strap.
This article lists 8 steps, but the actual production process is more complicated. I just selected a few relatively important explanations. Leather, glue, wire, edge oil, die cut, interlayer, processing technology, design, quality control, all of which will affect the quality and price of the final product.