Meet the Enormous Articulating Trucks Built to Haul Molten Hot Slag

The slag pots can hold as much as 300 tons of liquid metal at 1,500-degrees Fahrenheit.

Specialized heavy vehicles always amazes me. There are countless highly specific vehicles, designed to do incredibly difficult jobs, that most of us have never heard of. Before today, I didn’t even know molten hot slag was a thing, never mind the massive, articulating trucks that are designed to haul the stuff. Not only are slag pot carriers real, they’re awesome.

For those as new to slag as I am, it’s the byproduct of smelting metal and is a molten substance made of waste metals that sits atop the desired molten metal. While it’s technically a waste product, slag is used in a variety of different applications, such as filling potholes or covering parking lots, which means it needs to be separated from the molten metal it covers and then transported to storage. That’s where slag pot carriers come in.

Kress is one of the companies that makes slag carriers and the amount of different kinds of slag trucks are nearly endless. That’s because each carrier is designed to the specifications of each job and for a specific-sized slag pot, which is essentially just a giant bucket that holds the molten metal. Hydraulic controls can tip the slag pots, to pour the liquid hot metal into slag dumps. That might not sound all that impressive, until you realize that the carrier trucks can carry up to 300 tons and 1,589 cubic-feet of liquid metal at 1,500-degree Fahrenheit. Some of the pots are so massive, they can seemingly fit three of the passenger cabs inside.

Transporting molten hot slag is an important, and potentially dangerous job, that I didn’t know existed until today but now I’m fascinated by. Imagine just driving along with a massive pot filled with molten metal that’s hot enough to turn an entire car into goo? As fascinating as that job is, though, I absolutely do not envy anyone who has it, as being responsible for not spilling any slag while driving sounds horrifying.

Got tips? Send ’em to