Old Design
Looking back at the first version of this forge is quite comical. I remember seeing a youtube video on this and just had a crack with no proper design, planning or thinking. The resulting forge is a metal bucket laced with high-temperature mortar with a cavity filled with BBQ charcoal briquettes and a graphite crucible I ordered off of ebay. I painstakingly drilled a tunnel through the metal bucket and mortar to feed a pipe with an airpump to constantly feed the briquettes with oxygen. I used bricks on operation to cover the internal cavity whilst still exposing the crucible so I could feed the cans into it. This suprisingly yielded some melted aluminium but took too long and was not pure enough.
Current Design
In the improved design I made a lid of the same mortar with handles for ease of operation. This design also used a propane torch fed into the furnace as the heat source, resulting in a much more consistent and faster heat up time. However, even still this had quite a long heat up time before it reached a temperature that consistently melted the cans. Lack of information was one of my biggest struggles during this process as I had no thermocouple or pyrometer to gauge the temperature and was left to regularly open the lid; a process that removed a lot of heat energy from the crucible system every time I checked. Another few issues were the safety of this design. As a can has a large air cavity, as it is fed into the crucible it often aggressively popped or crumpled which often led to the molten aluminium splashing outside of the container. Whilst many of these landed on the surrounding bricks one landed and rolled off my leg! Thankfully I was unharmed most likely due to the Leidenfrost effect but future iterations I will pay much closer attention to safety when working with these extreme temperatures.
Ultimately the design was much more successful, yielding multiple ‘ingots’ of aluminium, but I have learnt a lot on what to do for the next iteration of the design. The next iteration has actually not even been on my mind, most likely as I already achieved my first goal of turning Aluminium cans into ingots and now I don’t really have a goal.
Future Work?
- Improve safety features
- Temperature measurement system
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- Most likely pyrometry as this was my Honours thesis
- Modelling
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- I have seen software (Ansys?) that can model temperatures and these environments, this may be a good idea to give approximate time frames for heat up