Every jeweler, beginner or experienced, has a question in his head: how to melt gold at home. This is not as simple as it seems, because there are many pitfalls and nuances that should be taken into account by an individual who wants to engage in the business in question. For example, the metal should not be brittle and porous, as it turns out due to the action of oxygen on gold.
Let's figure out how to melt gold correctly. The question of how much remelting costs will also be raised.
What is needed for smelting
To melt this noble metal, you need the following:
- Crucible. Pure gold melts at temperatures exceeding 1000 degrees Celsius. Not everyone has a working container - a crucible - that can cope with such heat. But it can be replaced with raw potatoes. It is necessary to cut a hole in the tuber and put gold there. A container of natural origin will cope perfectly with melting.
- Forceps. Heat-resistant tongs are an essential tool when melting gold. They will have to touch the crucible frequently.
- A mixture of sodium carbonate and borax. It is used to make flux, which is added to gold before the smelting process. It takes two pinches of flux to clean every ounce of gold. The dirtier the noble metal, the greater the amount of this substance required for cleaning. Flux can also be made from baking soda and bicarbonate. When adding a substance, the contact between gold particles improves, and all impurities are better removed from the metal when it is heated.
- Oven or microwave. There is an option to purchase an electric furnace to melt metals or use a microwave. The latter must have a power of more than 1000 W, with a magnetron located on the side or behind the equipment.
There are furnaces sold at inexpensive prices that are specially made for melting metals. Such a device is designed for mixing several minerals at once, for example, gold, silver, aluminum, copper.
Attention! The microwave in which the precious metal was melted can no longer be used for domestic purposes. That is, heating and defrosting food.
If there is no oven or microwave, you must use a gas burner.
Maximum melting temperature of gold: the higher the purity, the higher the degree
Fineness is the specific concentration of gold in the alloy. The most popular hallmarks are 999, 585 and 375. The number reflects the ratio of gold content per 1000 units of material. 1 kg of 999 fine contains 999 grams of gold, and the remaining 1 gram is impurities. The rule applies: the higher the sample, the higher the melting point.
- 375 gold melts and becomes liquid at a temperature of approximately 600-750 degrees.
- 585 gold product - at a temperature of about 700-850 degrees Celsius.
- The melting point of 999 gold is 1064 degrees Celsius. The boiling point of high-grade gold (999) is about 2700 degrees.
Important! If you are interested in the melting point in Kelvin, then add 273 to the numbers.
The melting point of gold depends on its purity
Scrap melting (process)
You need to be prepared for the fact that there will be a lot of impurities in scrap gold. Sometimes their amount in the metal reaches 25%. Such scrap is not suitable for figure casting, but you can work with it using the printing method (that is, heat and stretch).
- First, you need to sort the scrap by color. The more copper it contains, the redder its hue.
- To speed up the melting process, it is recommended to divide the scrap into small pieces.
- Next, you need to carefully sprinkle flux inside the crucible and put the precious metal there. You need to start with larger items (if you need to melt a lot of things), and add smaller ones as the process progresses.
- So, when the gold objects are laid out in the crucible, the latter is placed inside the furnace and wait until the gold becomes completely molten.
- Then you should pour the resulting substance into molds. And after that, immediately harden the metal with water or alcohol so that products made of metal become stronger.
But what to do if you only have a gas burner made by yourself?
How to smelt gold ore?
Gold ore can be mined with an iron or diamond pickaxe and smelted in a furnace to produce gold bars. Gold ore is also called: Gold, Gold ore. Gold ore is present in Minecraft versions: 1.8.2, 1.8.1, 1.8, 1.7.10, 1.7.9, 1.7.5, 1.6.4, 1.5.2.
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Making a homemade burner
First, let's look at how to create a gas burner. To do this you will need the following materials:
- injector;
- sprinkler from sprayer;
- automobile pump;
- sealant;
- tin can with lid.
It is necessary to visually divide the jar with the lid horizontally in half, and make two holes for the hoses in the upper part of it. Insert the pump hose into one of them, and the hose leading to the sprinkler into the other. Next, connect the latter and seal the holes.
To check whether the container is sealed or not, you should pour a little gasoline into the jar and start pumping air. Ideally, it should fly out of the sprinkler hole. If this happens, you can start melting at home.
Melting metal using a torch
Using a gas torch, you can melt metal in a matter of minutes.
First you need to sprinkle the crucible with borax (flux), then put the scrap in there, which has already been crushed. The more borax, the lower the temperature required to melt.
Next, pour in alcohol, set it on fire and wait until it burns out completely. It must be remembered that the crucible must be placed on a refractory area.
Turn on the burner and adjust it so that the edges of the flame are yellow and the middle is blue. The process is carried out using an open fire, so the crucible cannot be heated quickly. A crack may appear on it. The procedure is carried out slowly and evenly. The flame is kept at a distance of several centimeters from the metal.
The redder the metal, the lower the burner should be lowered to it. This is necessary so that all the ligature from the metal disappears, and parts of the material are melted down faster.
At the end of the procedure, the precious metal is poured into molds and hardened with water.
Melting down pure gold
Unlike scrap, pure gold can be melted down in a barbecue with thick walls.
We light coals in it and place a crucible there with metal pre-cut into small pieces. You need to monitor the fire every minute and periodically blow it. When the metal is completely melted, it is poured into molds.
Tips for Beginners on Melting Pure Gold
- You cannot melt precious metal on a kitchen stove, as there is a high risk of starting a fire. Gold smelting is carried out either in a room specially designed for this procedure, or in a courtyard at a summer cottage (for example). Definitely need a table.
- Beginners are advised to consult an expert before the procedure.
- The individual must follow safety precautions, so he must wear a mask and goggles to protect his face. You should wear heat-resistant gloves and an apron when working.
- There should be nothing flammable near the melting point. This also applies to interior decoration elements.
- Beginning “masters” without experience should not immediately take on gold of the highest standard, as there is a high risk of spoiling it. You should start with 999 fine bullion, which can be purchased at any state bank. As for the crucible, you can buy it in online stores.
- To prevent pure gold from becoming brittle and porous, which will definitely happen to it because oxygen gets into the metal, it is necessary to shake it before pouring the liquid metal into the mold and only then quench it with water or alcohol.
- You cannot melt precious metal using a gas welding machine. After all, they only melt steel - the gold will simply evaporate.
- If the procedure takes place in artisanal conditions, not in a crucible, but in a potato tuber, then a hole is made in it and borax is poured into it. And only then do they begin to melt the metal.
- 24 carat gold is very malleable. Therefore, to make it stronger, it is necessary to alloy it with another metal.
Why is gold melted and mixed with less precious metals?
Gold is a hard, refractory metal that is often mixed with other metals such as copper, silver, iron, aluminum, and platinum. At the same time, it often changes color (it becomes white, brown, red). Purposes of alloys:
- Increased strength. Pure gold is easily deformed. Therefore, it is fused with stronger elements - this way you can get a harder material.
- Saving money. Pure gold is an extremely expensive metal. To save money, it can be fused with cheaper components - the price of the final product will be lower.
- Giving gold a unique color (pink, white, green, blue, purple and other alloys). Ligatures of various metals are responsible for the corresponding shade.
To mix metals, they need to be heated to a certain temperature at which it turns from solid to liquid (melting phenomenon). This indicator is called the melting point. If necessary, the material can be heated even after it has melted.
Once a certain temperature is reached, gold may begin to evaporate (this point is called the boiling point).
Gold bullion production process
Remelting cost
Not many people think about starting a business by melting gold. But this is quite a profitable business.
There are many situations when, for example, a capricious lady does not like the shape of jewelry, or the size is not suitable. That's why many people order their jewelry melted down.
How much does it cost to melt gold? Experienced craftsmen name the cost depending on the weight of the jewelry. Therefore, it is not advisable to melt down jewelry that weighs no more than three grams. It's easier to fix - it will be cheaper. Items weighing more than 10 grams are usually sent for melting.
The cost of melting gold of the lowest standard is 500-600 rubles per gram.
The worst gold is found in cheap Chinese or Turkish jewelry. Few people would agree to do such hard work. The best sample is considered to be 585. The more qualified the master, the more he charges for his services. On average, the price ranges from 1200 to 1700 rubles per gram.
Interestingly, during the remelting process, the product evaporates by 10%. This happens due to metal splashing during melting and volatilization during remelting.
Remelting gold, the price of which is minimal, will take longer: the worse the quality of the metal, the more impurities it contains, which will take several hours to remove.
Table 1 - cost of gold smelting depending on the sample (Moscow prices)
Try | Cost of regular execution (RUB/g) | Cost of urgent execution (RUB/g) |
375 | 500 | 650-700 |
500 | 700 | 910 |
583 | 1200 | 1560 |
585 | 1400-1500 | 1820-1950 |
When do alloys melt?
Gold is characterized by durability, malleability, electrical conductivity, viscosity, and low resistance. It is thanks to these parameters that it has found wide application not only in the jewelry industry, but also in medicine, industry, and pharmaceuticals.
In its pure form, nothing can be made from gold in its natural state.
In order to make jewelry, this metal is not only melted, but also mixed with other precious and non-precious metals, such as silver. And gold can only be mixed with another element in a molten state. Therefore, it is pre-melted in special laboratories using certain tools and equipment.