This thread has really had me thinking and doing some research for the past week or so as time has allowed. I was mentally trying to design a way to utilize the vac process to evaporate and then re condense your solvent for reclaim while in the low atmospheric conditions sans any heat. While doing some research I stumbled upon Vacuum Distillation processes and some are using condensors to reclaim the solvent. A home made rig is definitely feasible I think the hardest part would be dialing in the vacuum (depending on your equipment) to maintain a satisfactory level of atmosphere in the chamber without going to low and evaporate your solvent so quickly that your condenser doesn't have a chance to do its job. I would imagine this could be controlled fairly easily with a ball valve (or some other sort of regulator) on the vacuum device and on a barometric relief (tube to atmosphere to intoduce pressure and raise vacuum level). If you wanted to go crazy you could even control the vac with a pressure transducer and relay to maintain a certain range.
A cheap vacuum pump you can use is a refrigerator compressor that you an easily convert for the duty. You can find them on eBay or other places for about 40$, an appliance repair shop would probably let you have one for next to nothing if they plan to scrap it anyway.
Most of the links I have are on my other device I'll try and edit them in later but some googling on 'DIY vacuum pump' and 'homemade vacuum distillation' would get you started if interested.
An interesting homemade apparatus that would probably be more suited to butane I would guess (only because I don't know what level of vacuum it is capable of) then ethanol was in a thread I stumbled onto on mycotopia. It was using two mason jars one as the evap chamber and the other as the condensor in an ice bath with a brake bleeder to control the vaccum in the chamber.
Probably out of the scope of what your looking for but it would be heat less, safe, and economical once properly setup as you could reclaim your solvents. Just my
but it's been fun researching and contemplating anyway. Thanks for the mental excerise
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