You want to pull a constant vacuum,l not just pull a vac and close the valve.
You could pull a vac and close the valve but you would need to then passively purge the oil… connect a second vacuum chamber and put on ice, put the oil chamber on heat
Let us know how it works out!
Hee hee, snicker, snark, thanks for pushing me to research Gast diaphragms, which gives me some ideas on where I might use my existing pumps!
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Glad my idiocy could be somewhat helpful. I’m open to suggestions, especially from master greywolf. We bought it from Amazon, easy enough to return the thing
This is the one I use for vac filtration and rotovap not my oven though. For my oven I use a 12cfm 2 stage rotary vane vacuum pump from ebay and if I’m doing anything etoh related I use my shitty bvv cold trap.
Bust most everyone here prefers a Welch wobi
This is part of the reason I want a quieter oil free vacuum. I want to run the vacuum constantly while purging, but my robinair is too loud and I don’t have a mist filter.
Man, I feel so stupid, I wish I had known quality rotary vane pumps were so quiet. An edwards E2M12 lists its volume as 52 db… that’s significantly less then the gast @ 68db.
edited
I did end up getting this pump as a Christmas present from the wife, couldn’t return/exchange because she does her Christmas shopping in October…
All in all, I’m happy with the pump. It’s all setup and running, quieter, no oil mist. I ended up getting a 4l vacuum flask, and this thing is almost too much vacuum. With the funnel full it pulls a deep vacuum quickly, pulling the etho through the filter so fast it comes out the funnel foamy. Some residual splash will coat the sides of the flask, but the vacuum doesn’t appear to be enough to suck the etho straight into the pump.
I should probably get a regulator for it though. In the photos it appears to have regulator behind the gauge, but mine did not come with one. I believe this is the one they sell, but I cannot find a photo or diagram anywhere
I ran the pump for roughly 30 hours until then oil appeared none reactive. I hooked up my old robinair to see if a deeper vacuum would stimulate a reaction. Roughly 5-10 tiny bubbles appeared, dissipated within moments. While tilting and running the oil side to side, maybe 5 more tiny bubbles came out. Oil was none reactive again within a few minutes. I figure I’ll do most of the run with my diaphragm pump and I’ll finish with my rotary
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You ran the vacuum for 30 hrs on your oil?
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Not consecutively. Like 12 hours the first day, then I killed the heat and vacuum, then another 12 the next day, probably 24 hours total at this point, plus another hour to finish with the rotary.
This is just for friend and family, not production, i would rather run the pump longer then needed and be on the safe side, don’t have any means of testing it
Would running it too long hurt anything?
Do you care about terpenes? You definitely don’t ever need to run vacuum continuously.
I pull mine down to -15 to -20 ish and leave it for 2 days and then call it good.
Anything more and you’re just boiling terpenes out. It’s a delicate game between evap the gas not the terps
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I do and I don’t, my main concern is safety since I can’t test my product. I would rather sacrifice terps then hand out product with butane or ethanol in it. This oil is for carts, so I’ll be adding terps back in, I even decarbed in the same chamber.
I use to pull the deepest vac I could with my robinair, seal it off for hours, then pull again like 6-12 hours later, but only for a few minutes. I thought the big guys ran their pumps non stop when purging, heck someone earlier in the thread made a post about it
Plus this is the largest batch I’ve ever done, almost double my usual batch
If I’m making shatter I vac the whole time. I also get the oven to temp and then shut off the heat 
flip and repeat
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I’m not sure what you’re end product is, but if it has liquid terps in it. You can not purge like that. You’ll just be boiling terps out.
If it’s shatter the post processing is different for sure. All this depends on the consistency of the product.
Thick like shatter, lots and lots of vacuum.
Thin and watery low vac.
To each their own
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If your adding terps in, why do it under vacuum at all? Heat it and stir it. Voila
Honestly I didn’t know I could use less vacuum and achieve a complete purge. That’s was one my concerns when buying this diaphragm pump, because it’s limited to -29hg, I was unsure if it was enough vacuum to fully purge the etho
I decarb under vacuum because; until recently I didn’t have a hot plate stirrer, was told ovens are inconsistent and not ideal, and I read decarbing under vacuum helps reduce oxidation and help preserve some of the color, which it seems to be working. I don’t have a pressure vessel to decarb in so I achieve a similar principle of removing oxygen to retaining color at the cost of terps.
I only reintroduce terps when mixing the oil before filling carts. I heat and stir, just bought a homogenizer
I didn’t think losing terps was a big deal for carts considering most are made with distillate. I did turn a bunch of crumble/sugar pho and turn it into nice hard shatter before decarbing it, I guess it’s because i boiled off the majority off the terps.
I also thought terps boil off based on temperature not pressure? I use to never exceed 160’f until I started decarbing in the chamber
Vacuum reduces the boiling point of everything in the vacuum.
If we’re talking about the terpenes that come from the garbage material that disty is generally made from then yes you’re right, we don’t care at all about saving those terps 
If you’re making bho and like the natural terpenes from your product you should try to save the terps.
If you’re happy with what you’re producing then don’t let me steer you in another direction.
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Appreciate the info, I’ll try it low and slow next time and see how I like it. I’m just paranoid about residue solvents
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Solvents we use have very low boiling points at atmosphere. Bringing under vac makes it even easier to pull it out.
What are your extraction parameters?
Are you jarring it? Or going straight to the vac chamber?
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I’ve been buying oil from a friend. I then winterize, purge, decarb and introduce hemp terps. I used canna terps last time, but I have about 30ml of hemp terps left to use.
I’ve debated dissolving some etho to see if I can get it to crystallize. I would love to make my own terp sauce, but I haven’t figured it out yet. I know I could redissolve in butane, but I don’t have a vessel for that
You also need to flip your Slab to adequately degas.
May also wanna check out some tips and tricks Tricks of the trade
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