Above is the complete set up. I bought a second hand hairdryer to give the blast! This is attached to a length of PVC tube. I had a bucket of sand and water ready in case of any mishaps, and used welding gloves, overall and a full face mask for safety. Sorry I have to keep repeating the disclaimers everywhere, but I don't want a law suit!
I used one of the test pieces of foam and added a sprue by hot gluing.
I packed the mould into the stand in 2 stages. I made sure there was plenty of sand in the cavities and tamped it down.
here you can see the complete mould setting with the sprue just proud of the top.
here is the completed piece - a faux polystyrene candle holder! I managed to spill molten aluminium around the hole, so there wasn't enough material to completely fill the cavity. The reaction was immediate, with the foam vaporising and catching alight immediately, at which point it is important to continue a steady pour.
The finish of the aluminium isn't great, and had some impurities through it. I have since learned that I need to 'pig' the aluminium. this basically means smelting it one, removing the impurities, and casting it into ingots to cast again. This means that on the second cast, and hydrogen gas take on on in the first smelt will burn off.
I got really excited at this point and decided to recycle this object into another shape to try and achieve more definition and a better finish.
It was at this pint disaster struck! As I was only using a tin-can crucible, I sprung a leak on the second firing, and saw the aluminium leak into the bottom of the furnace. This was a very depressing site!
I packed up my set up, and sulked for a while, but reflected on the process and what I head learned through doing it. I am now resolute in developing the process to a more refined level - confident I can turning these process into viable objects!
Disclaimer: This is a DIY project and Chris Jackson takes no responsibility for any injury,accident, loss or damage should you choose to engage in a similar project after reading this blog. In this, or any similar project, due care and diligence should be taken and always wear the proper safety equipment and take relevant precautions. If in doubt consult an expert or trades person.
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