Bert writes:


Not cooking oil; vegetable or animal derived oils will go rancid over
time and don't handle really high temperatures very well. Mineral oil is
much more appropriate.

transformer oil can be toxic and is difficult to find

Traditional transformer oil contained PCBs. The new stuff doesn't.

MFJ sells 1 gallon bottles for $30.

There's been no PCB's in transformer oil (or anything else
sold...) since 1979. GE is still trying to clean up the Hudson
River.

http://www.mfjenterprises.com/Produc...oductid=MFJ-21

Thank you. This is the coolant for the motor controller
we built; for an electric Miata we've named QAR. The heat
sinks have copper tubing embedded in them. We need thermal
conductivity and electrical isolation since the heat sinks are
200V apart, and are not referenced to the frame.

We tried mineral oil but the viscosity is way too high.
Fluorinert would be ideal but would likely cost more than all we
have spent to date. We're looking at DOT5 brake fluid as well.



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