How Cast Iron Pans Are Made by Hand at Borough Furnace

“A piece of cookware is a very tactile intimate product. It’s something that someone who has it at home is using it everyday, their food is touching it everyday, and so we’re very specific about how we treat that surface,” says Liz Seru, co-owner of the handmade cast iron cookware company Borough Furnace. “We’re only trying to make products that will last forever, that are useful, and the process informs its value.”

The small shop creates cast iron skillets, oven-to-table bakeware, and Dutch ovens. The molds for each of these items are first designed digitally, and then a machine-produced pattern is created. “That helps us with the design process because we get to live with things for a while,” says John Truex, co-owner of Borough Furnace.

Once the team has a mold they like, the creation process begins. First the mold is packed with sand. Then, at the induction furnace, which melts about 200 pounds of iron at a time, the metal is mixed with carbon silicon and melted. This melting process is tricky, explains Truex, because there’s no good way to take the temperature of the molten metal since any thermometer placed in it will melt. Therefore, the team has to use a trained eye and get a feel for when the metal is right, both so that it doesn’t freeze before it hits the mold and that it doesn’t burn through the sand. When the molten metal is right, it’s poured into the mold. After it is cast and cooled down, the mold is dropped on a vibrating machine called the shakeout, which breaks the sand apart to reveal the pan.

At this point, the pan’s surface is sanded down until a fine surface is created. Then it’s shot with tiny steel balls to give it a micro texture. From here, the team makes the pan in one of two different finishes: they can season it, or enamel it. For the seasoned option, it’s whipped down with flaxseed seed oil because it’s very high in fatty acid which bonds well to the pan when baked, creating a sealant. This finish helps give the pan a non stick layer, and seals in the raw cast iron which is susceptible to rust.

Borough Furnace is the only U.S. producer of enamel cast iron. Enameled pieces receive an “enamel slip,” which is a spray similar to those used in glazing ceramics, composed of glass, clay, and powder. Their mix is specially engineered to expand and shrink with the pan as it goes from an oven to room temperature to keep the enamel from chipping.

“I think making these things by hand informs so much of what it is. The idea that you’re getting this tool that was made for you, that took a lot of care to do it,” says Seru. Truex adds, “More and more people are in tune with where their things come from. I’m really interested in being connected to the product all the way through. We try to make things that we’re proud of.”

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