Soft Metal Foundry
Project Background

Although close-combat weaponry is really no longer a useful thing to own, for many people the construction of blades, armor and the like still has a place in the world as a fine art. Personally, I appreciate the amount of hard work and care involved in forging, casting and grinding swords and hammers, and on occasion during the past decade I have use scraps found around the house paired with store-bought flat-bar stock steel to make my own. Metal casting is a powerful tool in the manufacturing of certain types of weaponry, especially hammers, as well as countless other fabrication applications. I was particularly interested in using a foundry of my own to cast an aluminum hammer.

I happened across a generic video involving the pouring of molten aluminum into an ant hill thus creating a positive casting of its underground structure which got me thinking about how easy and fun it would be to create my own small-scale foundry. After watching a few YouTube tutorials describing similar processes, I settled on my own method of building a foundry and within the next few months had nearly all of the necessary materials. My Dad and I mixed Plaster of Paris together with water and generic play sand and, using a garbage can and a 5-gallon bucket, formed the outer housing of the foundry.


Luckily for me, my stepdad’s shop had a long-expired carbon dioxide fire extinguisher which he gave to me to use as a steel crucible for melting soft metals. Using a hack saw I cut off the top leaving me with slightly over two gallons of liquid volume within the remaining shell. The steel walls of this crucible are around 1/8-inch thick and quite capable of withstanding the extreme temperatures found in soft metal foundries. Steel and iron crucibles do deteriorate over time, but I only expect to be using the two-gallon crucible for extremely large casting projects. I have another thinner, smaller fire extinguisher crucible which a few friends from Boy Scouts and I used to melt down around 200 aluminum cans into a clay-pot-shaped ingot.

Although I know that the pure aluminum found in aluminum cans is subpar for casting, it is a cheap source of aluminum, so I have been saving most of the cans that we normally would have recycled in Illinois. As of mid-2017, I had collected an estimated 2946 cans based on the assumption that each can weighs 12 grams and the measured 77.94 pounds worth of cans. I am eager to finally cast my Thor hammer project, including the aluminum head and brass handle end-cap, as well as structural components for my lathe and pieces of my Treasure Rubik’s Cube.

Detailed Description

When actually using the foundry, I will need to be extremely cautious for multiple reasons. If anything does go wrong, and if I haven’t taken all the necessary precautions, it could potentially cause permanent bodily or environmental harm. I made the mistake of not adding any kind of mesh material into the foundry walls while pouring the plaster which would have acted as a composite reinforcement. I only have the matrix component, so structurally the foundry walls are brittle and weak, making them susceptible to cracking. If the wall fails when exposed to extreme heat and I don’t have anything to support it, the whole setup could collapse. If I don’t have a method of supporting the crucible as well, which I now plan to have, it may collapse with the foundry walls, spilling up to 2 gallons of molten aluminum onto the surrounding ground.

Handling the crucible is another major challenge especially if I do ever plan to completely fill it. I will need to fabricate a clamping device that can safely and consistently lift and maneuver the heavy crucible before I can even consider trying to cast something. It is mainly these reasons that are preventing me from moving forward with casting any of my aluminum or brass casting projects, with the addition of having no location currently available to me that would permit me to cast anything on their property. For now, these projects are on hold. If I were to make another foundry in the future, I would likely either make a much smaller one as I should have done to begin with, using Plaster of Paris and a reinforcing structure of steel mesh such as steel wool or steel screen, or I will follow the more expensive method of stacking fire brick combined with Kaowool. This will likely be necessary in the future if I wish to work on smaller casting projects.

  • LinkedIn
  • YouTube
  • Facebook