Looking at the windows of expensive jewelry stores, we are delighted with the beauty of products and the skill of jewelers. The art of turning a precious metal into a luxury item in the imagination of many people is a kind of sacrament, a special skill that not everyone can master. How are rings that beckon with their beauty born? What is the path of the precious metal from the sketch to the incarnation in an expensive piece of jewelry? What is a flask in jewelry and what is it used for?
Features of the profession of a jeweler
The profession of a jeweler requires more than just creativity. The jeweler must be careful and patient. In this case, there are many nuances, the observance of which requires utmost precision. The jeweler works with high temperatures and red-hot metal, the danger of this profession requires endurance and physical strength. A jeweler is not only a designer who comes up with sketches and works with a file underbright lamp light. This is also a foundry worker, managing red-hot furnaces and molten metal, lifting heavy plaster molds and monitoring compliance with technology. The arsenal of a jewelry master is full of unusual devices that a simple man in the street has not even heard of. For example, a flask. What is a flask and what is this device used for? Our article will tell about this.
Opoka in jewelry
Despite all the innovations and the high level of jewelry making technology, many of the jeweler's working methods have remained unchanged since ancient times. The process of casting rings, for example, has changed little. To answer the question of what a flask is, you should find out how the jewelry casting process takes place.
To make a ring out of precious metal, the jeweler uses a special refractory cylinder into which hot metal is poured, molding mass and wax blanks are placed. This is the flask.
This device is used to hold the sand during compaction in the process of obtaining a mold into which the precious metal is poured. You can make a flask yourself, the main thing is that it be made of refractory material. Some craftsmen make a flask from a pipe cut or roll it from a sheet of iron. The photo shows a modern metal flask.
The molding compound is already poured into this flask, inside of which there are wax blanks. The next step is the calcination of the flask in a red-hot furnace, this proceduretakes place in the foundry.
Application of a flask in a foundry
Delicate as the final decorations are, they go through a very harsh path through the red-hot furnaces of the foundry. Here is what the casting process looks like:
- Products enter the foundry in the form of wax blanks, which go through the molding process.
- The wax blank is placed in a special refractory metal cylinder - a casting flask.
- Then the flask is placed in a red-hot furnace for calcination. The temperature in such a furnace can reach 1000 degrees. The wax from the flask is smelted, and in this form there is a place for the precious metal.
- After the flask is calcined and the mold is formed, metal is poured into it. The jewelry casting process takes place in a vacuum, preventing the formation of voids and the ingress of foreign debris into the mold.
- At the final stage, the caster takes out the piece of jewelry from the molding mold and proceeds to its final processing and polishing.
Gypsum flasks for jewelry making
What is a gypsum flask? In form, it does not differ from the more common metal. Its only difference is the material and the need for stepped heating. Gypsum flasks are most often used for small jewelry casting, and not for industrial casting. In order for the casting process using a plaster mold to be successful, the temperature regime must be observed, otherwise the mold will crack and become unusable. This is the most convenientdo in a special electric annealing furnace, as the temperature can be regulated there. The annealing of the gypsum flask is carried out in several stages:
- Heating at temperatures below 100°C. Keep the flask at this temperature for at least an hour.
- Then the mold should be in the oven at 250°C for two to two and a half hours.
- After this time, the temperature should be raised to 450 ° C and annealed for another hour and a half.
- Only after that you can raise the temperature to a maximum of 750 ° C and anneal the mold for about three more hours.
The annealing time depends on the size of the opokich: the larger it is, the longer it takes to anneal it.
Disposable flasks
Having learned what a flask is and how it is used, it is easier to understand the intricacies of the process. It no longer seems so complicated, rather interesting and simple. Modern technologies allow you to try to make your own jewelry almost at home. The Chinese market offers a wide range of disposable molds with ready-made molds. All that is needed to work with such a mold is the required amount of precious metal and the ability to melt it. They are used by both jewelers who do not have their own foundry, and freelance craftsmen who make jewelry to order.
