Vacuum Oven

[PeopleWish]

What Vacuum Oven would you choose and why?

http://www.cascadetek.com/ovens/tvo-2-vacuum-oven

Basically because it comes pre calibrated and its plug and play.

 

[Hashmasta-Kut]

i've heard really good units are available for around 650, so this seems a bit pricey, tho maybe its really great too

 

[PeopleWish]

which make and models are you talking about?

 

[montroller]

He is probably talking about the used models on ebay. The cheapest ones I could find that would fit our application where ~ $1,500. I am a little sketched by the used ones because most of them are in questionable working order. A lot of the descriptions I was reading said they bought the unit in a mass auction or some company went under and they took all the assets so they don't have the capabilities to test if it works properly or not.

That being said I am sure if you lurk long enough you can find a good deal.

 

[montroller]

I want to buy this one from MTI by the end of this year, hopefully.

 

[Hashmasta-Kut]

which make and models are you talking about?

i dont know specifics, but here is a quote about it:

"Across international, a buddy of mine has an MTi oven and we were thinking MTI buys their ovens from Across and re-labels them, same product at a fraction of the price."

 

[hammalamma]

What Vacuum Oven would you choose and why?

http://www.cascadetek.com/ovens/tvo-2-vacuum-oven

Basically because it comes pre calibrated and its plug and play.

Those are really nice, a bunch of cool features. I find the biggest problem with vac ovens is size, I wish I could fit a 11x15" pyrex in the one I use. If I could bring my pans inside and straight to the vac oven it would save a lot of time and effort.

 

[JColtrane]

don't waste your money on a vac oven .... spend it on a real pump that will pull to 10 micro tore, like an edwards RV12 ... and vac with no heat. Vac ovens are over rated, just my $0.02

 

[Hashmasta-Kut]

Those are really nice, a bunch of cool features. I find the biggest problem with vac ovens is size, I wish I could fit a 11x15" pyrex in the one I use. If I could bring my pans inside and straight to the vac oven it would save a lot of time and effort.

if you are going to vac it anyway maybe instead of using the big purging pyrex you can use a smaller vessel that will fit in an oven easily. its only essential to keep it in a large container for heat purging really, isnt it?

 

[Flying High]

don't waste your money on a vac oven .... spend it on a real pump that will pull to 10 micro tore, like an edwards RV12 ... and vac with no heat. Vac ovens are over rated, just my $0.02

I am interested in hearing about your no heat purge tek. In my experience, the oil needs to be closer to a liquid in order ffor observaable offgassing to occcur for a long enough time period to completely purge any nasties...

When I have used vacuum alone, I noticed the oil was solidifying quickly, which stops all bubbling. While I could call this finished, taking the same oil and heating to 110F and placing back under vacuum results in the oil bubbbling/offgassing rapidly, sometimes for as many as forty more hours... I should mention I use a digital micron gauge,, and consider a fulll purge at 110F to be under 500micron....

I think a vacuum oven large enough to hold the big Pyrex dishes mentioned above is a must have feature. Ideally, I would want at least three shelves in order to hold at least three of those Pyrex.

For me, the advantage to a vaccuum oven would be the ability to run truly thin film purges in larger quanities...

Would anyone who has a vacuum oven be willing to share what they feel are the most importaant features to look for when shopping for a new oven, maybe recommend a brand?

 

[midwestHIGHS]

I was going to say the same thing Flyinghigh. Heat is essential to proper purge under deep vacuum, without it your oil will not be viscous enough to release solvent even with the strongest vacuum pumps pulling on it. Your oil will become stable under vacuum and still have shit load of solvent left in it, unless your purging oil that has been extracted from fully decarboxylated material, then your oil might be viscous enough to release solvent with no heat.

Hammalamma what size is the oven you have access too?
hmk- Thin film purging is essential to both heat and heat w.deep vacuum purging.

 

[PeopleWish]

hin film purging is essential to both heat and heat w.deep vacuum purging.

How thin are we talking like a few grams?

Could we not purge a pyrex full at a time at ~115f for like 24hrs and achieve "solvent less" non-viscous stability?

 

[Kushed_]

You need to be careful about buying used lab equipment. It may need to be decontanimated.

 

[maxlax1574]

You cannot just put used lab equipment into service. You need to have it professionally refurbished. You have no idea what kind of contaminants were in thee or if they are safe. Try www.vacuumpumpsupply.com for help.

 

[OGShush]

How thin are we talking like a few grams?

Could we not purge a pyrex full at a time at ~115f for like 24hrs and achieve "solvent less" non-viscous stability?

As thin as you can possibly get it in my opinion. You can purge a few grams with just heat if you have time and patience, but the more grams the thicker the slab and the harder it is to purge.

The problem is achieving the steady 115F or whatever the temperature is under the vacuum. That's why a lot of us are dreaming of a vacuum oven. Every cubic centimeter is heated to the same temperature whilst under vacuum.

If you are talking about a non vacuum purge at 115 for 24 hours it could result in a fully purged product, but likely at the cost of some terpenes through oxidation. I'd bet $20 that it would wax up because of residual moisture (boiling point of water =212). The reason vacuums are so desirable is that oxidation slows greatly in a vacuum (this is why foods are vacuum sealed) and boiling points being lowered (this is why you can boil water at room temp in a vacuum).

 

[PeopleWish]

Yah pulled the trigger on an oven, best thing since sliced bread!

 

[OGShush]

Yah pulled the trigger on an oven, best thing since sliced bread!

I'm green with envy right now. Where'd you get it and how much did it set you back? Do you have any comments on the consistency of your finished product?

 

[blaster528]

would like to know how well this worked out for you and what model and price you got and paid if you wouldnt mind please

 

[midwestHIGHS]

Which one did you end up going with?

Brand new, used? Tell us more

 

[PeopleWish]

I got a used "Precision Scientific Napco 5831 Lab Vacuum Oven #2" for 850 bucks off ebay.

I purge for 48+ hours at 30hg~ 105-110F and the shatter is of the best consistency that I have been able to achieve.

Not to mention you simply place your dish in the vac oven, pull your vacuum and sit back n relax. With the vac oven I am able to do much larger batches, specifically thicker slabs that are smooth and "bubbleless".

Amazing value. I recommend ebay for finding your vac oven. Simply search for one in an area near you and offer to pick it up and pay cash.

Never looking back.