Short Path Distillation

[Permacultuure]

GW,
is that glassware rated for high vacuum? It is a very large glass vessel to be puling that hard. hoping you checked before recommending it...

I bet we are going to start seeing a bunch of implosions/explosions with all these amateur non-chemists playing with cheap glassware at high vacuum.

lets be safe about this

I'd be surprised if the Eden labs vessel could maintain the vacuum required....maybe enough to distill, and maybe for a while, but eventually that large bulb could implode. Scary.....

I agree fully with Regis. When buying glassware make sure it's rated for vacuum as many of these setups are not, which is reflected in price. I'm told the longer annealing time increases the price and strengths.

 

[A6 Grower]

Are you speculating? Or have you used this glass setup before?

lol right, ive seen many setups with this head and it works just fine when kept at a proper temp

 

[Intoxicus5]

Yes, this is the setup and apparatus I know many others are using.

 

[Intoxicus5]

Not saying it's the most ideal.
Only that is confirmed to be in common usage for THC distillation.

 

[HG23]

Honestly man, I use a Claisen adapter and haven't used the standard setup as linked by Intoxicus5.

I was given that advice from someone who has ran the pictured setup and thought it was far from ideal. Sorry to misrepresent, I really should have stated that.

 

[Permacultuure]

Where do you use the adapter? I don't see how that fits in? It's essentially just a y adapter right? Sorry I'm a lil confused

 

[HG23]

It replaces the whole distillation head and condenser. It's nothing big. Just a little more efficient I think, but like I said I haven't used the other kind and am still sorta figuring this one out in all honesty.

If you take a look at a Claisin with Liebig vs the standard short path, it looks like a more direct path for the vapor to get to the condenser IMO. I'll send you a pic on IG as it's easier for me right now.

 

[HG23]

Here is a small pic. See how the neck is shaped differently?

 

[snake11]

Not saying it's the most ideal.
Only that is confirmed to be in common usage for THC distillation.

Most common?? Not by people in the industry. I have not met one professional that uses a setup like that.

 

[A6 Grower]

Your Claisin with Liebig condenser is WAY longer then that short path head that was posted. And the short path head that was posted also comes in a jacketed version to keep the temp stable and make it easier to keep warm.

 

[G.O. Joe]

High vacuum is only 1 mm. more dangerous to glass than the 759 mm's before it - there isn't glass rated for high vacuum, except for seals having some specified limit. Like on Eden's resin flask, which might seal well enough. Or anything that teflon tape can't fix.

All distillation glassware and most other lab glass is convex - vacuum increases its physical strength - and flat bottomed glass meant for vacuum is thick and not meant to be heated, because thickness adds thermal stress.

Thermal stress and physical damage are the problems you should focus on. A little bumping of glass on glass or anything harder can possibly cause damage, a chip, a little star. You cut glass by making a single fine scratch. It's much too easy to cut a RBF exactly in half with a little thermal wizardry that many people have discovered, without looking for it or trying to develop that skill.

It's true there will be breakage if DIY distillation suddenly catches on, and this might happen under vacuum, but blame operator error. The chemistry gods are not on your side if you skip organic chemistry - even skip reading .edu tutorials, watching clowns on youtube instead - and go straight to distilling THC.

 

[snake11]

A safety screen is a good idea if distilling. Here are a couple of glass safety sites that have good info.

http://www.scilabware.com/uploads/pdfs/2010/technical_information_glassware.pdf

http://www.uvm.edu/safety/lab/safe-handling-of-glassware#Vacuum

http://www.sigmaaldrich.com/labware/glassware-catalog.html

 

[Gray Wolf]

Glass has its highest strength under compression and it lowest under tension, especially if there is a small fracture or scored line to propagate.

The maximum vacuum pressure it can see is about 14.7 psi compression at sea level, so a round boiling flask, essentially a globe evenly distributing the stresses under compression, is highly forgiving until you shock it under vacuum or start a propagation point with a handling micro-fracture.

Way more forgiving than it would be at 15 psig internal pressure.

 

[Permacultuure]

Go joe, as I understand it, the thickness isn't what seperate the two, but the anealling time. So it may be only one mm thicker but a longer anealling time increases strength. Which in turn would combat the thermal stress and physical damage risks, no?

When you say high vacuum is 1mm thicker but then say there isn't glass rated for high vacuum, it confuses me? So there is high vacuum glass ware but you just feel that it is equal to the 1mm thinner option that isn't rated for high vac?

 

[Permacultuure]

View attachment 332477
Here is a small pic. See how the neck is shaped differently?

No vigreaux?

 

[G.O. Joe]

Go joe, as I understand it, the thickness isn't what seperate the two, but the anealling time. So it may be only one mm thicker but a longer anealling time increases strength. Which in turn would combat the thermal stress and physical damage risks, no?

When you say high vacuum is 1mm thicker but then say there isn't glass rated for high vacuum, it confuses me? So there is high vacuum glass ware but you just feel that it is equal to the 1mm thinner option that isn't rated for high vac?

Something got lost in translation there. I'm not trying to dazzle or baffle anyone, but there is no attempt to make my posts easy to read so that's my fault - because I don't care, and that's my fault too.

Atmospheric pressure being 760 mm. and high vacuum not starting until 1 mm., once you get to the high vacuum range, you've already done 759/760ths of the evacuation, the pressure differential on the glass.

The earliest really high vacuum pumps were made of delicate glass, and in those days you had to make them yourself out of soda-lime glass tube. McLeod gauges were used to measure that really high vacuum and they're all broken now, but it wasn't vacuum that broke them.

I don't know which glass manufacturers take the most and least care in annealing, the most established glass manufacturers are the most knowledgeable I guess. Only a few pieces of glass I have are not from the major brands. I've broken a lot of lab glass and it was all my fault except for a Chinese 24/40 powder funnel that exploded to a hundred little bits as it was in transit to me, even though it was in bubble wrap and there was no obvious damage to the box. Yes, bad annealing was exactly the thought there when that was unwrapped. Longer annealing times are given to thicker pieces of glass, and that piece being a mix of thick funnel and thin ST joint. It would be a good idea to build a polariscope and check cheap glass with it before use.

An overlong annealing time is undesirable because the components of the borosilicate glass separate. The thin glass distillation kit parts don't need the long annealing time of thicker glass.

 

[sog army]

I offer classes teaching people to make clear raw with a short path distillation setup and heidolph brand rotary evaporator.. If interested please PM ME>

 

[Gray Wolf]

It would be a good idea to build a polariscope and check cheap glass with it before use.

Good idea! It will very accurately high light any residual stress patterns in the glass.

 

[Permacultuure]

Thank you for the clarification Joe!

 

[HG23]

No vigreaux?

The Vigreaux indentations would cool the vapor before it gets to the receiving flask and would likely get gummed up, impeding the process.

I wrapped the claisen in foil, ran hot water through the condenser and it didn't get gummed up too bad but I had a shitty heating mantle and really shitty, unwinterized oil. There were likely a lot of problems with my setup. I'm just going to save up a little while for a Kugelrohr instead of trying to improve it.

The claisen adapter seems to be a lot cheaper than those short path heads and with the liebig on there as an extension it can easily be used with 5L boiling flask.