How to Build a Single Tank Biodiesel Processor

Now, almost everyone has heard of biodiesel, but few know that this environmentally friendly diesel fuel replacement can be made in a corner of a garage, using waste vegetable oil as the main ingredient. One only needs three basic ingredients to make biodiesel: methanol (or ethanol, if you're a corn lover), oil (new or used), and lye (caustic soda). This article will tell you how to build a simple, straightforward single-tank biodiesel processor out of materials you may be able to round up for free.


  1. Image titled Build a Single Tank Biodiesel Processor Step 1
    Gather together the few common items listed under "Things You'll Need."
  2. Image titled Build a Single Tank Biodiesel Processor Step 2
    Assemble the drum.
    • Cut a large opening (about half the top) in the top of the steel drum. You may also be able to find a drum with the top already removed.
    • Drill a 1.5-inch hole in the bottom of the drum. You will attach a pipe to it shortly.
    • Weld the 1.5-diameter pipe in the hole at the bottom of the drum.
    • Attach the 1.5-inch brass ball valve to the pipe. This is the drain valve. Brass is not necessary, but it offers the greatest durability.
    • Drill a hole in the side of the drum at the bottom, same size as the heater element. You can find heater elements in old hot water heaters or purchase them at a hardware store.
    • Fit the heater element properly, making sure it is not touching the side of the drum.
    • Wire up the heater element.
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    Assemble the chemical mixer.
    • Attach one pulley to the rolled steel rod.
    • Attach the other pulley to the spindle of the electric motor.
    • Weld the propeller to the other end of the rolled steel rod. You can use cheap shelf brackets as propellers.
    • Attach the rod, pulley and propeller assembly to one side of the hinge. This will allow you to be able to move the propeller/mixer when necessary.
    • Weld a piece of angle iron across the top of the drum. This angle iron (or similar) offers support for the mixing apparatus.
    • Weld the unattached side of the hinge to the angle iron so the propeller and rod assembly sits in the middle of the drum. The hinge should swing the propeller and rod back and forth.
    • Mount the electric motor on the side of the drum. You should be able to mount the motor directly to the drum without it tipping the drum (unless your motor is from an old Cadillac or something).
    • Fit the belt to the pulleys and tighten by wedging a block of wood into the hinge. A tight belt is necessary to mix the biodiesel.
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    Fashion a simple wooden measuring stick with 10 litre increments. The measurement stick will aid in processing biodiesel.


  • If you don’t know how to weld, you can fashion a container that uses threaded pipe or industrial adhesives.
  • This is just one version of a simple biodiesel processor. You can use other items that you may find cheap or free. The basic idea is that you need a large, durable container, a mixer, and a way to heat the oil while mixing. Use your imagination!
  • Consider placing your entire processor on a stand with wheels. This will make your single stage processor portable and adaptable to most any space!
  • Think of your single tank processor as a large blender. One can easily make a blender batch of biodiesel, and the processor described above is simply a large rendition of a blender.
  • If you don’t have access to a small motor, there are other options. One can use a drill with a propeller in the chuck to mix the biodiesel. There have even been models of single stage biodiesel processors that mount a bicycle on top of the drum, effectively stirring the biodiesel by mounting the stationary bike and peddling away!
  • It is essential to have a leak free container to ensure that the ingredients’ proportions are correct and to keep messy vegetable oil from creating a slick out of your garage.


  • Both ethanol and methanol are highly flammable liquids, and unfavorable conditions may result in flash combustion.
  • Lye (Sodium Hydroxide) is a strong base (alkaline) and will cause serious burns to the skin in a very short time and can cause blindness in SECONDS if splashed in the eyes. Chemistry-style goggles should be used whenever using Lye.
  • Research how to correctly and safely process biodiesel before making your first batch.
  • Place your processor in a well-ventilated area. The mixed chemicals will result in fumes that can be hazardous to your health. If the processor is going in a garage or outbuilding, make sure to place the processor near a door or a window that will open.
  • Sodium hydroxide can cause blindness in seconds. It hydrolyzes protein quickly, leading to severe eye damage. Cataracts, glaucoma, adhesion of the eyelid to the cornea, blindness, and loss of the eye may occur after eye exposure.
  • Lye is a caustic ingredient, and contact with skin--especially wet skin—-will result in severe chemical burns.
  • Make sure that your heating element is never in direct contact with flammable materials. Use the heating element to preheat oil prior to the addition of methanol or ethanol.
  • Flush exposed or irritated eyes with plain water or saline for at least 30 minutes. Remove contact lenses if easily removable without additional trauma to the eye, otherwise sodium hydroxide trapped beneath the lens will continue to damage the eye. If pain or injury is evident, continue irrigation while transferring the victim to the hospital.
  • Making biodiesel is addictive. Creating your own single stage processor may make you an oil baron.
  • If skin is exposed to Lye, it will first begin to itch, then a burning sensation will set in. If exposed, flush with cold water for several minutes.
  • For more information about safety and handling Lye, see

Things You'll Need

  • 55 gallon drum.
  • 1/2 or 3/4 Hp (small) electric motor. An electric drill will also work.
  • Two pulleys which produce 250 rpm and a max of 750 rpm at mixer blade. You will not need the pulleys if you use a drill to power the propeller.
  • A belt for the above.
  • 12 inch (30.5 cm) rolled steel rod. The rod can also be shorter or longer—it just needs sufficient propellers to mix the contents of the entire drum.
  • Two steel shelf brackets (for the blade).
  • 1 1/2 inch (38mm) brass ball valve.
  • A hinge and a spring to act as a belt tension device.
  • 2000-watt electric water heater element. Lesser or greater wattages will simply increase or decrease the time to pre-heat the oil.
  • A water heater thermostat.
  • 1 1/2 diameter piece of steel pipe 3–5 inches (7.6–12.7 cm) long with male threads on one end.
  • Assorted tat: angle iron, wood, screws etc.

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Categories: Reduce Recycle and Reuse | Environmental Awareness