Finn is not a huge fan of chemistry this semester. Her grades have wobbled between “terrible” and “passing” with peaks and valleys along the way, and we’ve had to stay on top of her studies every night to keep things on track. I can understand her indifference; chemistry was never my strong suit (I had no patience, a raging case of ADD, and a terrible grasp of basic math) but the stuff she’s learning is light-years beyond what I was exposed to in my school. She completely surprised me last night, however, when I showed her the latest iteration of my silicone mold project.

So far I’ve done three metal pours after I got a silicone mold to set properly. The first pour was terrible because the metal didn’t find its way down into the cavities fast or smoothly enough before hardening, so I pulled it out after it cooled and re-melted it. The second time I used the sharp end of a file to guide it into the cavities but the fill was still inconsistent. So I pulled the metal and took the time with an X-acto knife to carve out all of the edges of the mold as much as possible to open things up. Then I did a third pour in three stages. This one was much more successful but still didn’t fill the entire mold. I’ve learned it’s very hard to control molten tin before it cools—I suppose I need to get it hotter than I have been—but even then I’m not thrilled with the results. The tin is very malleable when it’s cooled, making it easy to bend, and my design has a lot of small, easily bent details.

Showing this to Finn, she was fascinated with the cast and asked to make some molds and casts of her own. After I mentioned I was thinking about making some kind of small smelter to try aluminum instead of tin, she idly suggested I try using resin instead of metal.

Sometimes she surprises me with her wisdom.

Resin looks to be a much easier substance to work with, is tintable, and the heat resistant variants get closer to the melting point of tin: I found one at 300˚F, which I think would be good enough for something mounted on a metal box in direct sunlight. It’s worth a shot in any case, so I’m going to pivot to chemistry and leave my foundry days behind.