Things You'll Need:
- Latex or nitrile gloves
- A scale capable of weighing to a gram
- pH paper
- Lye (sodium hydroxide 97%+ granule form)
- Methanol (99%+)
- Used cooking oil
- Blender
- Hot plate for heating the oil
- Large lidded container for settling the mixture
- Filter apparatus, filter paper, pump for filter
- Graduated cylinders, beakers, containers for measuring lye
- Clean workspace (garage or laboratory)
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Step 1
Determine how much oil you have to start with. Measure a fifth or 20 percent of that total to determine the amount of methanol you'll need. Keep in mind that you'll need 3.5 grams of sodium hydroxide for every liter of oil. Don't measure it out until you're ready to start: it absorbs water from the air, and water interferes with the process.
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Step 2
Dissolve the sodium hydroxide into the methanol and mix thoroughly until completely dissolved. Make sure this is securely covered because methanol and sodium hydroxide absorb water.
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Step 3
Filter used vegetable oil (skip this part if you are using store-bought oil). Preheat oil to 55 degrees Celsius (130 degrees Fahrenheit). Add vegetable oil. If you're using used cooking oil, you'll need more sodium hydroxide than if you're using pure cooking oil. Mix the oil for about 20 minutes or longer. Keep the lid on your blender to avoid spillage.
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Step 4
Transfer mixture into a lidded container. Allow the mixture to settle for 8 to 24 hours. The longer the better.
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Step 5
Observe your mixture. The biodiesel is the top layer. The bottom layer is glycerin. After settling carefully, decant the biodiesel layer into another container, not allowing any glycerin into your diesel. If they get mixed, you'll have to wait for it to settle again.
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Step 6
Pour the biodiesel into your gas tank. The fuel, if produced correctly, is ready to use in your car's diesel engine. It can be used as your sole source of fuel or mixed with regular diesel.
