I wondered about heat too, Jim and have decided to follow you plan. Bushido's method - as he said - is not for amatuers (sp) so I'll stick to the easy and safe method
This is a fascinating thread.
Simple potstiller. Slow, single run.
(50 litre, propane heated pot still. Coil in bucket condenser - No thermometer, No carbon) The Reading Lounge AND the Rules We Live By should be compulsory reading
If you just want the THC, then only soak the plant material in clean, high strength ethanol (minimum 70%), for a maximum 20-30 seconds, and agitate while soaking. Then quickly strain off through a fine alcohol proof filter. Any longer will draw out a whole bunch of other stuff, such as waxes and chlorophyll, that have nothing to do with the plant's psychoactive or medicinal properties, though they will sure as hell add extra 'flavours'. But the THC alone has a subtle and quite pleasing range of smell and taste, so adding the extra stuff in will just mask it.
Also, if you extract the THC and leave it in solution with (ethanol or isopropyl) alcohol, it will keep indefinitely. Alcohol prevents it breaking down in the presence of sunlight.
Actually, THC degrades in isopropyl in the presence of UV light, and maybe even other spectra of light (can't recall for sure), and I think to a lesser degree in ethanol as well. So you would not want to leave it in solution in alcohol for a long time without it being in an amber or other non-clear glass.
What you said above about extraction time and pulling bad-tasting chlorophyll etc is right on the money though. I've done iso extractions exactly in that manner (but left it in contact for slightly longer, 1.5 minutes), and got a beautiful clear, clean red oil.
The only downside quality-wise about the iso extraction is that a lot of the terpenoid constituents that give each strain of cannabis its (sometimes) unique flavor and aroma are not extracted by iso alcohol, resulting in the end product being not as tasty as, say, butane-extracted oil (assuming that the maker of the butane type knows how to correctly purge the trace butane at the end, a skill in itself).