Foundry
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The HoTD Aluminum Can Recyclery Foundry
Detailed Implementation Plan
By “Gravity Mike” Saleski

MISSION: The mission of the aluminum can recyclery foundry is to interrupt the aluminum can waste stream from the live music bar Burning Man theme camp “Hair of the Dog,” aka HoTD, and reduce the volume of aluminum cans taken from the playa back to the default world.

METAL SOURCE: Now it’s true, aluminum cans are actually a pretty poor source of aluminum for a foundry. They have high surface area for the volume, so as they melt oxygen is absorbed through the surface creating ‘dross,’ which does not pour and must be removed from the melt as waste product. Also, paint and plastic liners result in largely carbon impurities in the melt, called ‘slag,’ and must also be removed from the melt as waste product. At an industrial refinery, more aluminum can be extracted from the dross and slag, but this requires toxic chemicals and is not suited for small-scale use. I will recycle the slag and dross produced by this foundry.

Remember:  you’re not drinking beer, you’re making art!!

FURNACE: The furnace is homemade. A couple of inches of a cement/sand/vermiculite mix is coated on the inside of an ash can. The burner is made with a piece of ½” MIP with a venturi inside, inserted into a piece of ¾” MIP that is part of the furnace assembly. The gas line begins with a 90-degree ball valve, followed by an 18psi regulator, followed by a needle valve, followed by a certified and full-pressure rated flexible line. This line will be covered with large angle iron during operation to prevent accidental liquid aluminum spills and the like on the live line. All items are properly rated for the pressure (or much more) and for propane. (all parts purchased from http://www.flameengineering.com/). There is also an induction fan to force even more air into the burner (the venturi effect is not enough to draw adequate air, especially with the lid on the furnace).

CASTING: Sand Casting of metals has been done since about 4000BC and is still largely used today to cast metals! A moist sand/bentonite mix, called ‘green sand,’ is used to create single-use molds. Moisture control of the sand is an important aspect of ‘the art.’ Consequently, all sand casting on the extreme-low-humidity playa will be done in the evening hours. Melting cans into ingots does not require the use of casting sand and may take place at any time.

FINISH WORK: Cast items must be separated from the casting structure of the runner bar, sprue and pop-up holes, and gates. This is done with a hacksaw and/or jewelers saw. Following that, the items typically require some grinding, filing, and sanding to achieve the fully finished look. All of these actions will take place on a specially designed work stand where a small vise and grinder and mounted just above a container that captures falling aluminum particles.

WORKSPACE DESIGN, SAFETY, and MOOP CONTROL: Most workspace design elements in this project must take both safety and MOOP control into account. MOOP control is a serious issue with this project, and a simple canvas floor cannot be placed down in the ‘hot zone’ since any spilled liquid aluminum would ignite it! Workspace Design decisions and the safety and MOOP considerations behind them will are discussed in the following bullets:

  1. The general MOOP containment philosophy is to develop work processes and practices that are generally designed to contain MOOP. Secondary MOOP containment will also be utilized assuming that some items will escape primary containment. It is important to note that aluminum is not magnetic, and this process is inherently messy, so good design and work practice is paramount to the success of the MOOP plan.
  2. Secondary containment in the cool zone can be a canvas tarp floor. It is likely that small bits of casting sand and aluminum filings will escape primary containment. The area will be patrolled and cleaned daily.
  3. Secondary containment in the hot zone must be something that small bits of liquid aluminum (likely) or a spill (unlikely but plausible) will not ignite. Possibilities are plate steel provided by BMorg, simple square-foot patio bricks, or sheet metal over plywood. Regardless of choice, the are will be patrolled and cleaned daily.
    1. Plate Steel: will certainly work, but is not self-reliant, and possibly cannot be easily moved around to adjust camp layout.
    2. Patio bricks: supposedly spilled metal on concrete can cause steam explosions. For my volumes of aluminum this does not seem to be so, although repeated exposure of hot metal to concrete does eventually break the concrete down. Cinched together, such patio bricks should be successful secondary MOOP containment system that is self reliant, inexpensive, and adjustable in the camp layout.
    3. Sheet metal over plywood: for small drips this is an excellent light-weight alternative to patio bricks. I should conduct a controlled experiment to determine performance under the maximum plausible spill.
  4. Currently certified 20lb propane tanks will be the fuel supply. Probably 4 tanks will be plenty. The propane line starts with a 90-degree turn ball valve, then an 18 psi regulator, a needle valve, and a full-pressure-rated flexible propane line. This flexible line will be protected underneath a protective steel cover in the hot zone. The furnace is homemade but has been used around 100 times. I may build a new one with a hinged lid before the event.
  5. The Melt Tool Bucket is where the dross spoon and poker are kept, where dross and slag and are knocked off from these tools, and where the dross and slag cool before being re-recycled. Some aluminum will splash during the process – a reason for secondary containment.
  6. The Pour Table is where sand may fall from molds awaiting to be poured, or during cooling, and is also where any aluminum spill is most likely to happen. This table is a 2x2 foot plate of diamond plate with approximately 2-inch tall sides. The table sits atop cinder blocks.
  7. The Sand Box is where the messy process of producing a green-sand mold takes place, fully inside the sand box. All the necessary forms and tools are stored in an adjacent box on the sand box table. Most ‘spilled’ sand is likely to come from sand sticking to your hands and the outside of molds when moving to the hot zone. Brushing hands and articles reasonably clean of sand before removing from the sand box will be a Best-Practice work practice.
  8. The Finish Station consists of a small grinding wheel and vise perched directly over a MOOP-catching bin. Filing and sanding operations will also take place over this bin.
  9. PPE: A face shield, welding gloves, long pants and closed-toe shoes will always be worn in the hot zone. Eye protection and work gloves will be worn when using the grinding wheel.
  10. An ABC dry chemical Fire Extinguisher will be available in the work area.
  11. A First Aid kit with an emphasis on burn treatment will be available in the work area.
  12. I will be the only authorized operator. I may have assistants in the work area, but it will never be operated without my presence. Assistants need to know the PPE requirements, the basic process, and possess an awareness of what might be hot. There is a no-contact infrared thermometer on hand to measure the temperature of items.
  13. The emergency shut-down procedure is to turn the 1/4-turn ball valve to the OFF position. The hazard of extremely hot material (inside the furnace) remains for up to an hour. Spilled aluminum will cool enough to not initiate combustion of cumbustible materials 'instantly' in small amounts, in several minutes for the largest possible spill.
  14. One spare propane bottle may be stored next to the in-use bottle. Other bottles (two or three 20lb bottles) will be stored in the shade of my trailer away from the work area.

Foundry Layout