The melting point of aluminum is 660.32 °C, one of the lowest melting points among common construction metals. If you want to melt aluminum yourself, this temperature determines which melting furnace you need and how much gas a session will cost.
What is the melting point of aluminum?
The melting point of pure aluminum is 660.32 °C. This translates to 1220.58 °F or 933.47 Kelvin. This value applies to aluminum with a purity of 99.9 percent or higher, as specified in standard tables. In practice, 660 °C is often used as a shorthand.
If you heat it further, aluminum only vaporizes at a much higher temperature, well beyond the range of a normal melting session. For almost any practical application, 660 °C is the number that matters. At this point, solid aluminum becomes liquid and can be cast. It is also why aluminum is one of the easier metals to start with.
Why does aluminum have a low melting point?
Aluminum has a low melting point because the bonds between its atoms hold less energy than those in heavier metals. Therefore, less heat is needed to loosen the lattice and make the metal fluid.
In comparison: copper only melts at 1,085 °C, and unalloyed steel melts somewhere between 1,370 and 1,510 °C. At 660.32 °C, aluminum is well below this, less than half the melting point of steel. However, aluminum is not the lowest among casting metals. Tin and zinc melt at 232 °C and 420 °C respectively, while bronze and brass are above aluminum.
This low melting temperature explains why aluminum is so popular for casting and recycling. You need less fuel to liquefy a batch, and the metal quickly returns to temperature after a break. For those who want to cast at home, this low melting point is a great advantage: a simple gas furnace is sufficient.
Melting point of aluminum alloys
Aluminum alloys do not have a fixed melting point but a melting range: a temperature range in which the metal gradually transitions from solid to liquid. This is due to the added elements, each of which has its own influence.
Silicon lowers the melting point and improves castability, making it a popular element in casting alloys. Copper increases strength but makes the alloy more susceptible to corrosion, and magnesium improves hardness and weldability. Zinc and manganese are also common.
Depending on the composition, the melting range of common alloys is between 570 and 660 °C. Structural alloys from the 6000 series are close to pure aluminum, while casting alloys with a high silicon content melt significantly lower. If you are working with a specific alloy, refer to its specified range and not the 660 °C of pure aluminum.
Melting point of aluminum cans
Aluminum cans are made of an alloy and therefore have a melting range slightly below that of pure aluminum, roughly between 630 and 660 °C. Cans are popular for home melting because they are thin and can be found everywhere for free.
However, there are a few things to consider. The lacquer and coating layer burn when heated and produce smoke, so always work outdoors or with good ventilation.
Additionally, a can yields little: when empty, it weighs only a few grams, and a significant portion is lost as dross and oxide. To get a usable ingot, you quickly need to collect several dozen cans. If you want to cast seriously, clean aluminum blocks or casting scraps are more efficient than cans.
Melting aluminum yourself with a melting furnace
To melt aluminum yourself, you need a melting furnace that reaches well above 660 °C. A gas-fired melting furnace easily achieves this temperature and keeps the metal liquid while you are casting.
You don't melt the aluminum directly in the furnace, but in a crucible: a heat-resistant pot that transfers heat and holds the liquid metal. As soon as the aluminum is liquid, you skim off the oxide layer. Then you pour it into a casting mold made of graphite or into casting sand, depending on the desired shape.
Allow the crucible and mold to dry thoroughly and warm up beforehand. Moisture in the metal or mold can cause splattering. Always work in a ventilated area with heat-resistant gloves and safety glasses, as liquid aluminum at over 700 °C radiates intensely and splatters.
Are you going to start casting yourself? At Parrot Shopping, you'll find the melting furnaces, crucibles, and casting molds to work safely with aluminum. Our team will provide you with personal advice as your guide in the forging craft.
