Waste Oil: Fun, Free Furnace Fuel

The odyssey of building a waste oil-powered blast furnace from the Artful Bodger’s plans has consumed my free time almost since the inception of this blog. It melted its first 10 pounds of aluminum a month ago, but as I gear up for a proper post about it that includes video, here’s a summary of process-related personal anecdotes. Prior to building this furnace I ran a smaller one on charcoal for a couple of months. That became noxious and unsustainable, and my guilt at its use overtook the joy of casting.

This new furnace runs on waste vegetable oil (WVO), as from a fryer, or waste motor oil (WMO), drained from car crankcases. Both are disgusting substances, but even soiled they still contain incredible energy. A cursory search about the recycling of WMO yielded this South Carolina government FAQ sheet which, after an amusing paean to the joys of driving, says that most recycled motor oil is burned to heat municipal garages or generate electricity. Searching WVO leads to a lot of prating about biodiesel, whether you can make it in your garage and drive for free, etc. My process is vastly less complicated and resource-intensive. Either one burns in this furnace, but WMO burns hotter.

In order to secure reliable supplies of these scummodities, I visited two places across the street from the wine store where I work: a pizza joint and a garage, conveniently one door apart. I underestimated everyone in this “community-outreach” phase of my project, thinking people would be put off by my request for a 5-gallon bucket of their waste.

The owner of the pizza joint seemed to know exactly what I was talking about even before I showed him my crap phone video of the furnace’s first burn. He told me that pizza ovens use similar materials to blast furnaces, and certain components I might need could be bought from pizza shop suppliers.

A worker at the garage was glad to siphon off 5 gallons of stinking waste motor oil from one of their 6 55-gallon drums. He said someone comes by once a week to pick up the drums, but no one will care if I take 5 gallons here or there. He told me a funny story about over-pressurizing the drain station and hosing down an adjacent residential building with waste oil. The going rate is something like $50 for 6 55-gallon drums. Considering their weight, fuel cost in transport and reprocessing, it’s greener when I drive some half a mile to burn up on my driveway.

Finally, the owner of the local hardware I wrote about before advised me on furnace construction because he used to heat a barn with a water heater shell adapted to aerosolize and burn “drain oil.” He used to collect the drain oil from the marina where he worked and burn it through the winter.

An experience I had dreaded became the most pleasant of the build. Now I have a working furnace as green as one can be with local supply lines to keep it running. Stay tuned.