The Frybrid Still



frybridstillClay posted his filtration system on the Biofuels Technologies Forum under Filtration. It is based on the popular once Frybrid Still. The Internet Archive of the Frybrid website has construction instructions including parts lists and diagrams. Know that he no longer uses this system. He now uses a motor-driven centrifuge to clean his oil.

Freshly collected oil goes in the prefilter drum on the right. Once the drum has enough in it to process, It is pumped into the water heater and heated to 140°F. Heating the oil frees up some of the emulsified water allowing it to settle to the bottom of the still. The next day the temperature drops to about 110°F, and it becomes time to drain the water into a cubbie. The remaining dry oil is circulated through a 1-micron bag filter to remove the particulates. It needs to run long enough for the oil to go through the filter seven times. For example, if it takes 5 minutes to empty the water heater through the bag filter, then it takes 35-40 minutes to make seven passes. Now it is time to try a hot pan test. If it passes, then pump the oil through the bag filter into the tote for storage. The large tote is for storing clean, dry oil that is ready to use. It has two pumps. One for the still, and one to pump oil from the tote to the vehicle.

The pre-filter drum has a hole cut in the top the same size as the inside of a 5-gallon bucket. The hole is just the right size for a bucket strainer to drop right in. Bucket strainers are available on the internet at a variety of locations, including The 400 and 600 mesh are both good choices. Simple and easy to use, they strain out the big chucks that could plug up the pump without slowing down much. The pre-filter drum depicted on the frybrid site is a little bit more complicated but just as effective.

The Frybrid Still is plumbed almost the same as depicted on the Frybrid site with two notable exceptions. An overflow tube that dumps any overflow back into the pre-filter drum replaced the vent filter. Clay says he made that change after cleaning up a few spills.

The other change is the addition of a temperature gauge in the lower plumbing. It gives an accurate temperature reading when the pump is circulating the oil.

In the pump picture, the hose seen going up is the outlet up to the valves that direct the oil either into the top of the water heater or through the filter. The inlet goes around to the barrel AND the water heater.

On the manifold, the clear hose on the far right goes to the inlet on the pump. The black hose with the valve goes to the barrel and is plumbed in 4" off the bottom. Open the valve on the right and close the one on the left, and the pump transfers the oil from the barrel to the water heater. Only open the right valve to transfer oil from the barrel, the rest of the time it is closed. When the water heater is full of heated and settled oil, open the drain valve shown and drain 3-4 gallons of the crud off the bottom of the water heater. To circulate oil through the filter, open the left valve, and close the right valve.

This filter bag housing is from McMaster-Carr (part no 6870K59). It is aluminum and accepts standard size 4 bag filters. It's max operating temperature is 250°F, and it's max operating pressure is 300 psi. The pump Clay recommends to run the still is no longer available from Northern Tool. However, the Pedrollo pump at Northern tool is a good one. It is inexpensive and reliable. Just be sure to wire it up with a 6 amp inline fuse. If the pump starts to overheat, it will blow the fuse before catching on fire.

The 300-gallon tote was the latest addition to the setup. It eliminates storing oil in cubbies. If you look at the top of the bag filter housing, you see a pressure gauge. It is there to indicate when it is time to change the bag filter. The higher the pressure, the dirtier the bag filter.

Related Links

Frybrid Still Construction Instructions

turbofroggy's Frybrid Still - pictures only