In a world driven by the maker trend and creativity, having a metal casting at home It has become interesting for manufacturing and crafting enthusiasts, or starting a home business. This fascinating process offers the possibility of molding and giving life to a wide range of metal objects, from unique decorative pieces to functional components of engines, structures, etc.
In this article, we are going to see everything you need to know to have a metal foundry at home, in addition to recommending some must have products for it, and so you can immerse yourself in the exciting world of DIY with metals...
Recommended products
In order to start melt metals at home safely To be able to create things like a professional, you will need the following products:
graphite carbide crucible
Mold for molten metal
Bentonite powder to create custom sand molds for pouring molten metal
Metal melting furnace
Flameless Induction Heater
steel anvil
Wrought Iron & Stainless Steel
Blacksmith hammer
Thermal gloves
Foundry tongs
Upper heat shield
No products found.
Flame retardant clothing
Fire extinguisher
Antigas mask
A first aid kit
Other blacksmith tools
Other jewelry tools
What is a metal foundry?
A metal casting refers to an industrial or artisanal process in which a metal is melted and poured into a mold to shape a specific piece. During this process, the metal coming directly from the mineral or from previously produced metal pieces is subjected to a high temperature to reach the melting point of the metal or alloy.
Once melted, pour into a mold which has been pre-designed to create a specific shape and size. Once the metal cools and solidifies in the mold, a piece of metal with the desired shape is obtained, whether to create a jewelry object with precious metals, for mechanical or structural parts with custom shapes, or to create ingots and sell them.
This process is essential in the manufacturing and has evolved throughout history, using various methods and technologies. But think, if thousands of years ago you could smelt metal with rudimentary and primitive practices, with current technology you can do it at home quickly, safely and efficiently...
Steps
The casting process, whether in an industry or at home, is made up of a series of fundamental stages, on the table:
- First, the metal to be melted is obtained, either from pure mineral, from other pieces of that metal that we want to reuse or recycle, etc.
- This metal is introduced into a crucible, in which heat is applied in ovens or through induction, thus melting the metal when it reaches its melting point.
- The metal is transferred in its liquid state to a specific mold.
- Process of hardening or cooling the newly formed object.
- Review stage of the final product, subsequent surface finishes (painted, carving, hammering, welding,...).
Obviously, when the metal is obtained directly from the ore, some extra substances must be added to make the impurities are removed by the slag, although this is not necessary if you make it from already pure metal.
Emptying
Although the casting of a metal It may seem easy, you must keep several things in mind. And once you heat the material and reach the optimal temperature, the metal is ready to be poured in its liquid form into a mold. But this flow through the casting system and cavity is a crucial stage in the casting process. For this step to be successful, it is essential that the metal flows unsolidified through all areas of the mold before hardening, keep in mind that not all molds are simple shapes.
Influential factors in the emptying process include:
- Pouring temperature: It refers to the temperature of the molten metal at the time it is introduced into the mold. The crucial difference here is between the pouring temperature and the temperature at which solidification begins (the melting point for a pure metal or the liquid temperature for an alloy). This temperature difference is sometimes called "overheating." This should be as small as possible to ensure adequate filling of the mold, since both the oxidation rate and the solubility of gases in the liquid metal depend on temperature.
- pouring speed: refers to the rate at which molten metal is poured into the mold. If the speed is too slow, there is a risk that the metal will cool before completely filling the cavity. If the pouring speed is excessive, it can create turbulence and become a serious problem, which could cause erosion of the mold sand and trap gases and slag in the molten metal.
- Turbulence in the flow: occurs when liquid metal comes into contact with the walls of the mold and depends on the speed, viscosity of the liquid metal and the geometry of the filling system. It is important to avoid turbulent flow as it promotes greater interaction between the metal and air, resulting in the formation of metal oxides that can become trapped during solidification, deteriorating the quality of the casting. Additionally, turbulent flow can cause excessive mold erosion due to the impact of the molten metal flow.
Crystallization
To get one crystal structure in metals, a controlled cooling process is required after casting. The crystalline structure in metals is formed when atoms or ions are organized in an orderly and repetitive manner in a three-dimensional network, which gives the material its new and very interesting properties.
When a metal melts, the liquid state of the metal causes its atoms to be disordered, breaking their bonds and moving freely. On the other hand, if the metal cools, these atoms bond again, but in a disordered way. But if the cooling is controlled, the atoms can be made to adopt a desired crystalline structure. This is achieved through a uniform and very slow cooling.
During cooling, small ordered groupings of atoms are formed, and little by little they become more and more, producing the growth of the crystal and spreading the metal throughout the structure. However, this crystalline network could be altered after some work such as laminating, quenching, tempering, or forging, and a recrystallization process. This basically consists of heating the metal to a temperature at which the atoms break their bonds, and then cooling it again to obtain the uniform structure.
There are some other processes to produce crystals in metals, such as those that use metallurgical powder that is compacted and subjected to a sintering process with controlled heating so that the powders fuse and form a dense crystalline structure, but this is more complex...
What metals can I melt at home?
The answer to this question is: all. All metals can be melted, as long as they are within your reach, and are not dangerous or prohibited for sale, such as radioactive metals. The other thing you should consider to know whether or not you can melt a metal is the temperature reached by your induction system or your oven, since depending on the melting temperature of the metals, you will be able to melt only some of them. For example:
- Gallium (Ga) – 29,76 °C.
- Rubidium (Rb) – 39,31 °C
- Potassium (K) – 63,5 °C
- Tin (Sn) – 231,93°C
- Lead (Pb) – 327,46 °C
- Zinc (Zn) – 419,53 °C
- Aluminum (Al) – 660,32 °C
- Copper (Cu) – 1.984 °C
- Iron (Fe) – 1.535 °C
- Nickel (Ni) – 1.455 °C
- Silver (Ag) – 961,78 °C
- Gold (Au) – 1.064 °C
- Platinum (Pt) – 1.768 °C
- Titanium (Ti) – 1668 ºC
So much for pure metals, but we also have alloys that we can melt, like:
- Stainless steel: between 1,370°C and 1,480°C.
- Bronze: in the range of 900°C to 1,000°C, depending on the composition.
- Brass: varies between 900°C and 940°C, depending on the proportion of copper and zinc.
- Nickel-iron (Invar): is approximately 1,430°C.
- Aluminum bronze: It is generally in the range of 625-675°C.
It must be said that the way in which these metals are cooled (slowly or slowly) could modify their internal structure, making them harder or more brittle, and even achieve crystallization of its atomic structure to obtain smart metals…
Ferrous and non-ferrous metals
It is necessary to distinguish well between ferrous and non-ferrous metals, since they have different characteristics. On the one hand we have the ferrous metal:
- Ferrous: They are those metals that contain iron, such as soft iron, steel, stainless steel, etc., and thus up to hundreds of known alloys. Ferrous metallurgy accounts for approximately 90% of global metal production. Iron is noted for its density, its strength when combined with carbon, its wide availability and ease of refining, as well as its susceptibility to corrosion and its magnetic properties. The creation of iron alloys by incorporating various elements, in specific proportions, allows one or more of these attributes to be attenuated or eliminated.
- non-ferrous: refers to the process of melting any metal that is not iron or does not contain iron. Examples of these metals are lead, copper, nickel, tin, zinc and, in addition, metals considered precious such as gold, silver and platinum. It is essential to distinguish these casting processes from ferrous metals, since they require different procedures and resources, specialized depending on the metal to be worked. They tend to be more reactive than ferrous materials. Throughout the process, special filters are required to remove reactive gases that could damage the metal, such as slag or hydrogen, which could obstruct metal purification. In addition, dryers are used to keep the non-ferrous concentrates free of moisture and specialized sands are used in the preparation of the molds. In terms of techniques used, the principle of casting non-ferrous metals is similar to that of ferrous metals, although some specialized mold filling techniques are applied, such as pressure injection, which guarantees obtaining parts with much larger dimensions. precise and better quality surfaces.
Recycle and win
Casting metal at home is an exciting activity that, if done properly and safely, can provide opportunities to earn money, either by selling your jewelry, metal sculptures, etc., or by recycling a multitude of metal objects and selling the resulting ingots by weight. Here are some ideas:
- Jewels: You can melt down jewelry that you don't need or like (or other objects that you know contain precious metals), whether gold or silver, to create a unique piece and sell it by weight. Keep in mind that a gram of gold has a fairly important price…
- Electricity: Many electrical and electronic elements contain large amounts of copper, such as cables. If you have old wiring, damaged motors with their copper windings, etc., you can obtain this sought-after metal.
- Cans: Aluminum cans used for drinks can be melted down and the resulting aluminum then sold, a way to make a profit from something that is thrown away. Something similar can happen with the tin cans that are used for many preserves, although this other alloy is cheaper than aluminum.
- Others: whether they are pieces of beam, profiles, rods, scrap, pieces from a scrapyard, old objects, etc., depending on the type of metal they are, they can also be melted to recycle them and obtain other shapes or to sell them by weight at some point specialized.
Other ideas to do
Of course, if you want to get away from merely recycling and selling metal by weight, you can also do much more:
- Pieces: offers foundry services to create replacement parts or restore metal components for people restoring antique cars, motorcycles or metal furniture.
- Artistic and decorative casting: Create decorative home items such as door handles, furniture knobs, or custom metal lamps.
- Trophies and prizes: Supply local sporting events, competitions or awards shows with custom metal trophies and awards.
- Structures: Melt down metal to create structures that are rare or not easily sold, or perhaps parts for repairs to parts that are no longer manufactured.
- Jewelry- You can melt noble and precious metals to create your own personalized jewelry and become a fashion designer.
Safety measures for melting metal
Metal casting is an activity that involves significant risks, so it is essential to follow appropriate safety measures to protect your health and well-being. Below are some key safety measures to take when casting metal:
- Personal protection equipment: Always wear personal protective equipment, including safety glasses, appropriate boots, heat-resistant gloves, fire-resistant aprons, and, in some cases, hard hats and eye protection. You may also need a mask, since in some cases toxic gases may be produced that you should not inhale.
- Safe work area: Establish a well-ventilated, dedicated work area for metal casting, preferably in a workshop or garage. Make sure it is free of flammable objects and that suitable fire extinguishers are on hand. Also, if the area has low humidity, much better, since the presence of water in the environment could cause some problems in the process.
- Adequate ventilation: Home metal smelting can release toxic fumes and vapors when melting certain items. Use an appropriate ventilation system, such as a fume extractor, or work outdoors to avoid inhaling these dangerous chemicals.
- Fire control: Keep a dry chemical fire extinguisher rated for Type D (combustible metal) fires near your work area. Also have a bucket of sand or a fire blanket handy. Never use water for metals that are at very high temperatures, as this can cause a major incident.
- Safe casting equipment: uses furnaces or smelting equipment specifically designed for this task. Inspect the equipment regularly to make sure there are no gas leaks or electrical problems.
- Proper handling of metals: Handle molten metals carefully and using appropriate tweezers or tools. Avoid contact, splashes, etc., and always keep pets and children away during the process to avoid accidents.
- First aid: You should always have a first aid kit on hand near your work area and know how to use it. Burns are a common risk, so you should know how to treat them properly. And if they are serious burns, go urgently to the emergency room.
- Training and experience: Before you start casting metal, seek training and gain experience. Learn about the types of metals and their melting points, as well as safe casting techniques, what you can and can't do, etc. Familiarize yourself with the chemicals involved in metal casting and the associated risks. Make sure you know the specific safety measures for each type of metal.
Remember that metal casting is an activity that requires knowledge and experience, so it is important to learn from reliable sources and always be vigilant about safety.
Can I create alloys?
The answer to this other question is yes.. You can create your own alloys, as long as they are between metals that can be alloyed with each other, since there are some that cannot be mixed. Therefore, you should know what the possibilities are before proceeding to mix metals without rhyme or reason.
Virtually almost all metals can be alloyed, that is, combined with other metals or elements to create alloys with specific and new properties. The most favorable metals to the alloys are:
- Iron (Fe): It is a base metal for many alloys, such as steel, which is an alloy of iron and carbon. Steel is widely used in industry and construction due to its strength and durability.
- Aluminum (Al): Aluminum is alloyed with other metals, such as copper, silicon, zinc and magnesium, to create alloys that are lightweight and resistant to corrosion. Examples are aluminum alloys used in the aerospace and automobile industries.
- Copper (Cu): It is used in a variety of alloys, including bronze (copper and tin) and brass (copper and zinc). These alloys are known for their strength, electrical conductivity and aesthetic characteristics.
- Nickel (Ni): It is combined with other metals, such as iron or chromium, to create corrosion-resistant alloys, such as stainless steel and Monel.
- Titanium (Ti): It is used in alloys in the aerospace and medical industries due to its high strength and low density. The most common alloy is Ti-6Al-4V (Titanium-6% Aluminum-4% Vanadium).
- Lead (Pb): It is used in alloys, such as lead-tin, for soldering and counterbalancing applications due to its high density.
- Zinc (Zn): It is combined with other metals to create alloys such as brass and zamak. Brass is widely used in the manufacture of musical instruments and decorations, while zamak is used in castings.
- Tin (Sn): It is used in welding alloys and in the manufacture of objects such as kitchen utensils and packaging.
- Silver (Ag): It is combined with other metals, such as copper, to create alloys such as sterling silver used in jewelry making.
- Gold (Au): It is combined with other metals to create alloys used in jewelry manufacturing, such as 18K gold (Au-75%, Cu-25%), etc.
These are just a few examples, and there are many other alloys used in various industrial applications, from aerospace to construction and electronics. Alloys allow the properties of metals to be adjusted to meet specific needs in a wide range of industries.