Just noticed this thread. Wesson oil looks like it was cottonseed oil up until 2009. Now it is canola/corn/sunflower/whatever is cheaper. Maybe cottonseed is the ticket but is unobtainable now? I wonder if someone else sells the cottonseed oil. Maybe it is better than synthetic or could even be what is being used as synthetic by oil manufacturers? :-) I don't know the burning /boiling temp. of it. Maybe it could be mixed with peanut oil or synthetic or caster to keep the price down and use ether or acetone to help idle and acceleration a bit as a nitro substitute. (not more power though) Some commercial brands used soybean oil in the 1970's. I never liked it because it ran hotter than Klotz and caster, and left an ugly stain on the motors and smelled like something was burning. I still have a Cox Conquest and a VA .049 with a nasty stain from this oil.. I may have forgotten but I think Ucon or Ukon was the brand. I often wondered if mixing gasoline or some other mineral based fuel with methanol in just enough quantity to mix with a two stroke motor oil in maybe a 40:1 mixture would mix and lubricate sufficiently without rod bearings. The motors wouldn't have to be called slimers then. Any ideas or experimenter/rocket scientists want to try? Or know the smoking temp. of cottonseed oil and a manufacturer of it? Wesson had a process of refining it so it wouldn't smell. Maybe that is the same as degummed castor oil as an end product.
I'm doubtful any vegetable oil other than castor oil will dissolve readily in methanol in appreciable amounts - the reason was, as I stated earlier, castor oil is the only one that contains ricinoleic acid. This is the only vegetable fatty acid that has a -OH group in the middle of the carbon chain. This gives it an affinity to alcohols (which, incidentally, are defined as molecules with one or more -OH groups). That said, I suppose I should actually try the experiment rather than be dogmatic about it. I have heard of people experimenting (and using) soybean oil in racing fuels where mileage was important, but I've heard the results were less than stellar. Never heard of it ever being used in a commercial brand, though, but of course I haven't heard everything, either.
UCON oils are something else altogether - they are synthetic "oils" which belong to a group of chemicals called polyalkylene glycols (usually abbreviated as PAG). They are good for use in glow fuels mainly because they dissolve readily in methanol. The UCON oils are PAGs originally sold by Union Carbide, but now by DOW chemicals. The one mostly used by home brewers was LB-625, but there is a whole range of them, with different viscosities. They are used in a huge number of applications - some are water soluble and used in the food industry, for instance, and some are used as compressor fluid in airconditioners (I know of a airconditioner repairman in Chicago who uses the stuff - it's got fluorescent dye in it, by the way - to mix fuel). And I'm willing to bet a sawbuck for a donut that most "synthetic oils" used in commercial model fuels - and this will include Klotz - use PAGs (and most likely one of the UCON LB fluids) as a base. PAGs have a couple of big drawbacks, which have been discussed ad infinitum
here - they absorb water (and were thus deemed undesirable as automotive lubricants back when they were tested in trucks in Alaska in WWII), and they don't protect your engine from a lean run like castor oil does.