Catching Up on the Bronze

I can't believe it's been so long! Not sure what happened; I thought I had posted about our second round of bronze-making, but I missed it. And the subsequent casting session, too. So, here goes:

In June 2024, we made bronze again. We had made it successfully for the first time in May, so this was really just about making more, and getting more familiar with how the furnace and bellows worked. 

 

It was all pretty straightforward, and the furnace worked like a charm. It took less than two hours from set up to pouring. 

In the video, you can hear a big "crack!" near the end - we all got spooked! But it was just the concrete under the muffin tin that couldn't take the heat. See here:

We got ourselves two good muffin ingots. And while the amount of metal that went in didn't quite match what came out, I'm guessing we lost some through dross or spillage here and there.

 

In September, we tried to cast our homemade bronze into these plaster moulds:

But for some reason, it took a long time to melt our bronze, longer than it took to make it. Bronze melts at ~950º C but to make it you need to melt copper at 1085º C, so it really didn't make sense - it should have melted sooner. And we were using our box bellows, which raises the temperature much more quickly than the natural draught approach we first used to melt brass in 2023.

(The dog got bored and had a nap.)

It makes us realize that we still don't entirely know how to best use this furnace. How much charcoal to put in right away? Where to position the crucible? How much forced air to give it? When to replenish the charcoal? etc. There are only a few variables but they matter. It's exciting to know that the feeling of understanding something through experience is coming.

We cast a few objects. 

  

The pine cone isn't great because the original mould isn't great. The yonilingam came out pretty well, if a bit short. And the bee medallion has some pitting so can definitely be improved.

In October, during a trip to India, I visited an artisanal bronze workshop near Kumbakonam in Tamil Nadu. It is run by a family of sthapathis - hereditary bronze casters (in this case, for five generations). It was great to see their setup and way of working; their furnace is buried in the floor and they do lost wax with clay moulds (which we'll have to try making some day). 

(bronze on the left, wax pattern on the right)

And you should have seen the look on their faces when I told them I also do bronze casting at home and then showed them that yonilingam! 

At the end of 2024, we made some more plaster moulds for our next casting session.

But it's been so snowy and cold this winter that we haven't been able to fire up the furnace.

 

It's now March 2025, I think we'll be able to soon. And then I promise to post about before 9 months passes.