I have recently switched from butane to DME (Dimethyl Ether). This makes a product called DMO. Technique is very similar to BHO. All the same safety recommendations apply (i.e. NEVER do it indoors) but it is slightly less flamable. I prefer the flavour ...
Um, er, I know this is an old post, but really?
Firstly, I very much doubt it really is dimethyl ether, seeing at that's a gas at RTP! What I strongly suspect is being written about is Di
ethyl ether, which is a liquid organic solvent, with an extremely low boiling point - about 35℃!
Diethyl Ether is hellishly flammable (I'm not quite sure what "slightly less flammable" means to be honest), has an exceedingly low flash point (doesn't take much heat for it to spontaneously combust), and is heavier than air and collects at ground level, creeps across the floor 'looking' for a nice thermostat or other spark or hot point (even a hot plate or steam pipe can do it!) - then wham! Flashback!
It's heaps of fun! (if you like no hair and red raw skin or worse).
If it's in a sealed container it will rapidly build up pressure due to the high vapour pressure it exerts, especially in a warm environment! One common accident is the vessel suddenly rupturing or the stopper blowing out, causing liquid and vapourous ether to energetically spill, and risk a fire (plus it has the effect of a general anaesthetic, so careful not to breath in!).
Even batman would struggle to escape ether intoxication in a closed area filling up with ether vapour while waiting for the heating thermostat to turn on! Did I mention it can form explosive air mixtures?
Do please take care with flammable organic solvents! And please try to double check facts before posting advice regarding potentially very dangerous materials and processes. People have life-changing and fatal experiences doing this sort of stuff without knowing a great deal about what they're handling. One solvent may very well not be like another. Just changing your solvent in a known and practiced method can have unexpected negative consequences.
One point of note though, as diethyl ether evaporates at a very low temperature, it's easy to strip out of your oil, if you can set up a modest low pressure rig (even a water-powered vacuum pump will do - just slips onto a tap, and no need for a cold trap as with an electric pump) and a water heater, you shouldn't have worrisome traces left in it.
All in all it can have many properties that make it good for solvent extraction, but I honestly would not advise using it unless you really know what you're doing, and ideally have wet organic chemistry experience. The likes of butane and propanol are bad enough, ether, even outdoors, has the potential to cause some nasty accidents, and not just to the user! Your neighbours may not thank you if they live!
I may come across as a bit of an 'old woman' (for want of a better and less sexist expression) but I worked in advanced chemistry labs for about 12 years and know of what I speak.
Final little tip - something most people rarely hear about - there's a device called a soxhlet extractor that's designed to do exactly the sort of job of extracting active compounds from cannabis. It's a piece of glassware that recycles clean organic solvent into a glass vessel containing a large thimble made of something like filter paper which you fill with plant material. You then leave it running and it essentially distils the solvent so it's clean, and gradually fills the glass vessel submerging the thimble and soaking the plant matter.
When it reaches the top of the vessel it automatically syphons all the solvent, now containing some of the cannabinoids and terpenes, back into the reservoir where the solvent continues to boil and send clean solvent back into the vessel via a condenser. This will continue as long as the power is on to heat it, and the condenser has water flowing through it to cool it (and condense the solvent vapour into the vessel with the thimble). It doesn't leak solvent vapour as long as the water is running while the heat is on. You can leave it going for hours and it will wash your weed with solvent many many times until there's next to nothing left in it. If you really want to get everything out, you can even finish, change to a different solvent, then let it go for another few hours, then add the two solutions together and strip off the solvents (probably not worth it though - diminishing returns and all that).
You then need to strip off the solvent in a vacuum oven or rotary evaporator (not cheap!). Use a rotevap and you get most of your solvent back - very environmental! Using low pressure will keep the temperature required to boil off the solvent to a minimum thus protecting more of your precious active compounds.
These things ain't cheap though, you'll likely pay a grand give or take for something that will take an Oz in one go. Beware of very cheap one's as they may not be made of strong high quality borosilicate glass! Genuine Quickfit glassware is expensive for a reason, if you're saving plenty its because the risks are rising higher than you can see or appreciate. It also needs a heating mantle if one not bundled. Probably best to have some silicon grease or similar to stop the quickfit glass joints jamming. And that's before you sort out your method of cleaning out the solvent from the oil. Many things to go wrong if you've not done this before and not all of them very obvious. It's not the sort of thing you should learn by doing without some expert advice at hand.
There are many extra processes to further clean it and remove lipids and fats and all sorts of non-active crap, but there again, every operation will lose a certain amount. And the rougher your technique and equipment the more you'll lose, so fewer operations tends to be more efficient.