Metal Casting

Since I have a forge, I decided to see if I could also melt and cast metal as well. Well, I can.

Turns out, the simple start up to it is not too hard. At a minimum, all one needs is a seamless steel can (I used a can from re-fried beans), a longish steel pipe, an air blower, charcoal, some sand, rigid insulation foam, and a lot of aluminum soda cans. Cut the foam with a sharp knife, and pack into wet sand, leaving a hole into which to pore the molten aluminum. Do not worry about removing the foam, as it will melt when the hot aluminum is pored onto it. However, this also means you will lose the foam form.

Before I continue I have to say I am an amateur at this, and most of what I have learned has come from talking to professionals, watching Youtube videos, reading articles, and practicing. First, and foremost, always think safety. Wear safety glasses, leather gloves, close-toed shoes. Avoid inhaling any escaping gases, or getting too close to the fire. You are working with hot, volatile stuff. Small mistakes can have large consequences.

Start the charcoal, with the steel pipe shoved into the center of it. By means of the air blower (a vacuum or hair blower work well) stoke the charcoal. Put the steel can onto the fire, burning off any materials on the metal. Avoid letting the can get to hot (glowing red) or crushing the sides. The wall are thin, and when heated, become easy to pierce. Once they have a hole, the molten aluminum will pore out, which is not good. You are now ready to melt the aluminum.

Crush the cans before adding them to the steel can crucible. This reduces surface area, which reduces the chances of oxidization. Also, it lets you put more into the crucible. Fill the crucible and add back to the fire. You can put a lid on the crucible, which allows the inside to heat up faster and retain higher heat. This expedites the process, but also increases the chances of the steel can burning through. Once the aluminum is up to heat and melting, it does wick away some of the heat from the wall, meaning the crucible can is less likely to break, but only marginally.

Aluminum soda cans melt at, give or take, 1200 degrees Fahrenheit. After my first couple times, I figured out that melting temperature is not the same a poring temperature. You will want the metal to be somewhat hotter so it does not cool off too fast and not fill up the mold. Also, aluminum soda cans have a lot of gunk on them that will be in the melted aluminum. The outside is covered in paint, and the inside is coated to prevent the sodas contact with the aluminum. Luckily, it all forms together to form this produce called slag that forms to the top of the melted aluminum. This can be removed with most any metal rod, though one should be sure not to stir the metal, as this introduces gases to the metal.

Using a set of pliers, pull the crucible can from the fire, pore the mold, let set to harden, scrap away the sand, and cool the cast piece in water before touching. And that is the basic for doing it.

Now, this will produce from you a very rough product. Also, this crucible can will only work once, so you would need to replace it every time. Straight sand is very course and will leave the casted piece very rough. An open fire loses a lot of heat, meaning it takes longer to achieve the desired temperature.

The foam shape for an Assassin's Creed logo. This is my first cast.

Fresh from the sand.

After cutting off the excess and filing down the edges, this is the finished sanded piece. Not bad for the first time.

Other creations:

The tiny head is my third casting attempt. The second, while it mostly succeeded, ended up becoming fodder for later melts.

The leaf key fob was cast with the grooves in it. Once it was polished, the piece was coated with dark paint, and the outside layer was buffed off. This left the grooves darkened.

Making a Crucible:

So, I have begun working on making my own crucible. With the help of the internet, I finally found some help. Commercial companies are loath to share how their are made, for good reason. A number of D.I.Y. sites do have suggested methods, and to these I have turned. Pictured is the initial test I created before I fired it. Although the crucible is smaller than the actual one I want, I figured it was easiest if I started small and once I had made the process work, enlarge it. The walls of the crucible on my first attempt failed, as they were too thin and too poorly packed. While the lid (not picture) did seem to fire properly, without the pot section, I cannot test it with melting metal yet.