Core77 wrote an interesting piece about a couple of cousins in upstate New York who are using waste vegetable oil for iron casting. They brought their innovative idea to kickstarter and reached their funding goal, allowing them to build their furnace and micro-foundry.
Based in Syracuse, New York, Borough Furnace is a small metal-casting workshop founded by cousins John Truex and Jason Connelly. The crux of their operation is the Skilletron, a custom crucible furnace now on its fifth or sixth iteration that melts scrap metal by burning waste vegetable oil.
Truex was first introduced to the world of iron casting via a small cupola furnace, a miniature version of the old coke-fired furnaces that were the staple of industrial iron production for a long time. “Now most U.S. iron production is done in large electric induction furnaces; a lot of Indian and Chinese iron production is still done with large coke-fired cupola furnaces,” Truex says. Wanting to create a small batch of cast-iron goods like skillets and bottle openers, Truex and Connelly looked at a variety of furnaces and manufacturing options to see what would make the most sense.
The duo discovered that for the same amount of money they would need to spend on tooling for overseas production they could build out their own micro-foundry and prototyping studio in the States that would also allow them to explore new cast-iron products and objects—retooling and making their own production molds for each new piece. Investigating further, they found that existing cost-effective furnaces like cupolas were restricting in their ability to only cast iron and types of bronze; also, because of the coke fuel, they were extremely dirty. But more expensive crucibles, which can melt aluminum or any other metal cleanly, proved unacceptable in the amount of pollution and fuel the process requires.
“The waste vegetable-oil furnace was the next step, and the initial design was based on a few different home-published books about waste-oil furnaces, notably those by Colin Peck and Steve Chastain,” Truex says. “Where our furnace diverged from the ‘backyard casting’ predecessors was in trying to get the iron hot enough to pour thin-walled castings [for skillets] and in making it repeatable and consistent.” Thus was born the Skilletron.