Casting Bronze

 We did it! We cast bronze. 

Even though we had previously smelted bronze and melted brass, we were full of doubts with this attempt to finally cast bronze. Would the furnace get hot enough to get the bronze fully molten? Would the molds withstand the heat? Would the bronze cool too quickly while pouring? etc. 

It was such a thrill to crack open the molds and see that it worked!

This was the first time we made plaster molds for such high temperatures. We mixed the plaster 1:2 with sand.

And then mixed this into the water, and poured the liquid plaster into our boxes. 

Following a tip from our sculptor friend and neighbour Alex, we set some of the figures on an angle, to allow the hot gases to better escape during the casting.

(This was the angle inside.)

And then of course the wax burnout in the toaster oven, to melt out most of the wax, and then much hotter in the raku kiln to burn off the last remnants. 

And then on casting day, we wheeled our Mighty Clay Furnace out to the patio, and lit it up.

We packed our molds into containers filled with sand, in case any of them broke. Plastic ice cream tubs weren't exactly going to contain molten bronze should it have pushed through the sand, but they were better than nothing.

The bronze we were using was stuff that I had bought in Argentina about 15 years ago - kept all this time for this very day! (In places like Argentina there are still hardware and metal stores where you can go and easily buy this stuff off the shelf, unlike in Canada. At least 15 years ago, anyway.)

The temperature rose very quickly but the bronze wasn't melting fully, only at the bottom.

So we decided to cover the whole thing with charcoal, and worry later about what happens with the charcoal bits and ash when we went to pour it.

Right away the temperature increased even more and the bronze quickly melted.

(You can see the charcoal ash on top.)

So we decided to pour. 

There were these incredible lightning flashes of green, and the light from the molten bronze was so bright! It poured beautifully, especially when compared to the surface-tension issues we had when casting aluminum. 

We didn't have much bronze in the end, and decided to fill the biggest molds with the most robust walls, for fear the smaller molds would break (as Gloria's small one did while preparing the sand tub). These were two yoni-lingam molds. What a thrill to bust them open and see that it all worked!

What a beautiful material bronze is! Golden, weighty and warm, and of course, full of so much historical connotation. These cast objects are pretty full of pits (which may or may not be entirely fixable), and even a bit of what looks like charcoal, but for us at this stage in the game, they are absolutely beautiful anyway. 

Next time, we'll need to make more bronze with scrap copper and tin, and if that works, we'll try clearing out the dross before casting. And hopefully everyone can get a chance to pour their own.

It's been a long time coming, but we finally did it. A day not soon forgotten.