Aluminumis the most common alloy used in metal casting. There are several reasons forthis, but the main one seems to be availability and quality. Many metal castershave access to a large amount of aluminum with soda and beer cans that theycrush and melt down. Aluminum has several desirable properties for the metalcaster no matter if they are a hobbyist, artist, or are casting needed partsfor home repairs. Many who cast aluminum also love the alloy since it can beused in all of the varying casting processes giving it a wide range ofpossibilities. Aluminum is often used as a practice alloy for the first timemetal caster or for casters who are trying out new methods and ideasPet metallized film .Many of the small home furnaces that are found in most hobbyists foundrieswill be able to easily melt aluminum. It may even be possible to use charcoalthough many just use propane since they have it on hand for other alloys. Foryour first run at casting, charcoal should be fine. If you do choose to use soda cans for your source of aluminum you are going toneed a fair amount depending on the size of the item to be cast. Make sure tocrush the cans as much as possible before placing in the crucible or other areathat will be used to melt the alloy. Since any metal casting process can be used with aluminum the choice will restwith you. There are three casting methods out of the numerous methods availablefor aluminum that seems to be preferred by small time metal casters. Thesemethods are sand casting, lost foam casting, and investment casting.
Remember, though, aluminum can be used with any metal casting process so do notbe afraid to experiment. Sand CastingSand casting aluminum is very common and is a popular way to break in a newfurnace. Casters use sand mixed with a bonding agent to create a mold aroundthe item to be cast. The item, or pattern, is removed very carefully revealingthe mold. If there will be any empty spaces in the finished product then a coreis added to the mold. The core can be made of sand and is placed so that themolten metal fills the area of the mold around it. So, say you're making apicture frame you will place a cone where the glass will go so the moltenaluminum will not fill that area. Many choose not to use sand casting since it does not allow for fine detailwhereas other casting does, but it is inexpensive.Lost Foam CastingLost foam casting which is sometimes called evaporative casting.
The lost foamcasting is a form of sand casting. The entire process is relatively cheap andwhen used with old soda cans casting aluminum this way is great on the budget.A foam copy of what you want to cast is created and surrounded by a ceramic shell.You will place the copy in loose sand which will help to hold the shape duringthe pouring process. The molten aluminum is poured into a cup that in insertedinto the copy. The foam vaporizes and the aluminum replaces it filling the areain the ceramic shell. Removing the shell will reveal the aluminum casting. Thismethod is great for fine details but the copy is lost to the ages. Luckily,foam is not all that expensive.Investment CastingInvestment casting is commonly used by jewelers as it allows precise castingswith full detail. This form of casting has been around since ancient timesunder the name of lost wax casting. Investment casting involves creating a waxcopy which is then covered in slurry creating a shell, much like the kind ofshell in lost foam casting.
The molten aluminum replaces the wax which meltsout of the shell and can be collected for reuse. Artists and casters that needhigh precision parts favor this technique.Given the number of options that aluminum presents to the caster finding theright casting method will involve some time. To help decide which aluminumcasting process is best consider factors like quality and cost. Many metal casters use aluminum far more then they use other alloys like brass,bronze, or iron.