Biodiesel has a higher flash point/auto ignition temperature than diesel oil.
Here's my list of fuels, which may prove handy if you ever get invited to a Geeks Convention! Temperatures are in degrees C
Exact flash and ignition temperatures of oils/fat fuels cannot be given, due to their variability.
All the figures quoted below are published figures from reliable sources.
Flash points for vegetable oils/fats are about 140-190șC in a pressure jet burner spray arrangement- see video below.
The true flash point for vegetable oil is around 240șC
Diesel oils flash point: 70-130șC depending on grade and blend.
B100 Biodiesel flash point: 150-220șC depending on quality and feedstock vegetable oil/fat. B100 IS PURE BIODIESEL. When cut with regular diesel the number represents the biodiesel percent. B3 is 3% biodiesel for instance.
Auto Ignition point for vegetable oil is about 245șC.
An electric arc in air is at a temperature of over 3700șC.
Auto ignition points for various fuels show a wide variation:
FUEL AUTO IGNITION TEMPERATURE șC
Carbon monoxide 609
Ethyl Alcohol 365
Diesel [ #2 oil] 256
Kerosene [UK=paraffin] 210
Vegetable oil c.245
Oak [dry] 480
Charcoal [aged] 350
Bituminous coal 300
B100 Biodiesel c.235
For home heating purposes IMHO there is no point in converting WVO to biodiesel, as the methanol and other chemical costs make it only viable for use in engines or to deny Gummints' Revenue Men. And, Larry, you are right about the hazards of messing with lye and methanol - methoxide is a lethal poison that can enter via your skin. It is also self-anaethetizing so you don't notice the big hole you just burned right through your hand till you see your feet through the hole! DON'T MESS WITH MAKING BIODIESEL AT HOME!
Just clean the WVO of fries, chickens and dead customers, [I use a centrifuge], but a special burner is needed. Here's a typical WVO burner - but be aware, this is an advert....http://www.youtube.com/watch?v=q4ZriEMN0FQ&feature=channel
My atavar shows my version, still being developped.