Aluminium Casting WorkshopPosted: March 8, 2014
The casting technique Dallas taught the class was a sodium silicate sand casting technique. The compound is mixed in a big bucket with a large paint mixer and should be mixed for a long while to get rid of all lumps and to achieve a fine casting sand, this is then stored in airtight tubs as it reacts to the CO2 in the air causing it to go off and set hard almost like concrete. This sand is packed tightly around the object for casting, I cast an abstract polystyrene form I whipped up a couple of minutes before the workshop and a wax ammonite cast I had made the previous week. The polystyrene (white only) burns out and so is left in the mould during pouring, the wax cast was removed before the top of the mould was put on. The pour hole opened directly onto the polystyrene while the riser rose up from the wax cast impression, the two separate pieces joined by a flow channel. The sand is hardened using a bottle of co2 with a plunger Darlek thing on the end of the hose. The pouring of the aluminium was fun and quite exciting, it was a laborious yet satisfying process, I acted as both a pour’er and a scraper over 2 pours. I videoed the pouring and around the foundry in general. The end result was very satisfying, on the morning of Wednesday the 5th March I broke open the sand mould with a hammer and exposed my casts. They turned out well and after a clean up I realised I wanted to do more aluminium casting. I remembered a card flower former with an interesting pattern I had found months ago and wanted to cast, to create a vase like object. I approached Dallas and discussed the possibility of casting it. We talked about a few ways of proceeding with capturing the inside texture as well as the outside which would make it an even more interesting object in my eyes. The mould looks like it might be quite complicated and I am wondering about the perish-ability of the cardboard. I have decided I want to cast it and that it will be invaluable experience however well it goes.