Author Topic: confused in chromics sassy distillation writeup  (Read 2402 times)

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majic22

  • Guest
confused in chromics sassy distillation writeup
« on: November 27, 2002, 09:39:00 PM »
In Chromics write up in step 3 (just under the picture of the picture of the glass setup) it says..........

"While on the subject of flat bottomed flasks, it should be mentioned to NEVER use a large (>250ml) flat bottom flask under vacuum. The risk of implosion is quite high."



This is what confuses me.  The way i understood that statement was that you cant use a flat bottom flask larger than 250ml.....is this correct?  if so, why do they even make them? 

Also, i cant remember off hand without looking at my print-outs and files but somewhere in either the Bright star synth, the Nitro synth, or hex synth it calls for a vacuum filtration flask and if i remember correctly it is bigger than 250 ml.  WTF? 


Theres nothing to be afraid of, just concentrate, and trust the music.

raffike

  • Guest
There is difference in FB flask and filter ...
« Reply #1 on: November 27, 2002, 09:49:00 PM »
There is difference in FB flask and filter flask,filter flask is heavy-walled FB usually is not.

A friend with speed is a friend indeed

majic22

  • Guest
cool thanks
« Reply #2 on: November 27, 2002, 09:51:00 PM »
cool thanks

Theres nothing to be afraid of, just concentrate, and trust the music.

pHarmacist

  • Guest
use what you got..
« Reply #3 on: November 27, 2002, 09:59:00 PM »

Moriarty

  • Guest
What type of vacuum is being pulled?
« Reply #4 on: November 27, 2002, 11:39:00 PM »
The risk of implosion is low unless your friend's got thin glass and is using one hell of a pump?  Water aspirator?  SWIM wouldn't worry.  Something that pulls down to 15 microns is a diffreent story.  That might still be okay but tell your friend to get thick walled round bottomed flasks if he/she hasn't ordered something already.  If he/she has, SWIM'd use what is available but your friend does have something to lose if hot oils in a flask and the peanut oil in the oil bath go everywhere.  Your friend would lose precursers, which are getting really hard to obtain, probably break lots of expensive glass, burn things in his or her room (if he/she works in a residential room but SWIM has definately made some mistakes requiring recarpeting) and your friend might hurt his or herself.  SWIM's learned a thing or two and skimping on the right equipment and taking short cuts will make your friend pull his or her hair out.  Get the right stuff, tell your friend to make as few precursers as possible, follow the directions to a "T" and tell your friend to take his/her time.  Distill everything twice.  Just SWIM's thoughts and he's learned the "what-not-to-do's" the hard way.

Who wants to play cops and dope fiends?

hypo

  • Guest
pHarmacist!!
« Reply #5 on: November 28, 2002, 01:16:00 AM »
are you crazy? a vacuum implosion is _not_ fun. you'll never totally recover from all the glass in your skin and how are you going to explain the accident when arriving in a hospital with trillions of tiny shards sticking in your skin?

pHarmacist

  • Guest
Yes, I'm crazy
« Reply #6 on: November 28, 2002, 01:32:00 AM »
chill, fat chance that his flask will explode. 2 factors, combination of hard vacuum and thin wall do that, one factor seldom produce implosion... By the way, one should allways wear protection while working in bthe lab, for eyez, hands and a lab-coat. If the flask is in the fume hood it can't relly cause no harm even if it blows. Fuck, there are more damgerous things in the lab to worry about.


"Turn on, Tune in and Drop Out"

hypo

  • Guest
hard vacuum?
« Reply #7 on: November 28, 2002, 01:40:00 AM »
outside pressure: 1000mbar
weak vacuum: 15mbar
strong vacuum: 10^-something mbar
difference between weak vacuum and outside pressure: 985mbar
difference between strong vacuum and outside pressure: 1000mbar

not that much of a difference! and don't forget: when distilling,
the flask is heated => stress, that's another factor.

i strongly oppose to your statement "see if it breaks". when it
implodes, it's too late.

Moriarty

  • Guest
I pulled a light vacuum with a thin flask!!!
« Reply #8 on: November 28, 2002, 01:41:00 AM »
It's not that it's likely; it's that it could happen.  Think about the shape of a flat bottomed flask.  It's just beggin' to implode.  Would I take the risk?  Sure.  I admit it but I'd recommend this bee order some good glass (thick walled round bottomed boiling flasks) so that one thing that can go wrong can be excluded.

My thin walled flask was a 1000ml RBF and it didn't break under my weak vacuum, it broke when I was swirling after amalgamation.  Just put in the extra $20 and you might avoid a possibly large problem.  It's worth it.

Who wants to play cops and dope fiends?

Rhodium

  • Guest
Welcome back hypo! Pharmacist: Not many of the ...
« Reply #9 on: November 28, 2002, 02:44:00 AM »
Welcome back hypo!

Pharmacist: Not many of the people here are using a real fume hood, so flat bottomed flasks or scratched round-bottom flasks are definitive no-no's for hobby experimenters.

hypo

  • Guest
lab coat?
« Reply #10 on: November 28, 2002, 03:14:00 AM »
hi, rhodium  :)

> By the way, one should allways wear protection while working in bthe
> lab, for eyez, hands and a lab-coat

have you seen what's left of a lab-coat after a vacuum implosion?
not bloody much!  the 10000m of air are quite heavy...  :P

pHarmacist

  • Guest
well my lab-coat is 3 cm thick Pb, happy-hypo?
« Reply #11 on: November 28, 2002, 03:17:00 AM »
:) No, I've actually never experienced such a disaster in the lab, thanks god..

"Turn on, Tune in and Drop Out"

hypo

  • Guest
i'm always happy (well, almost..)
« Reply #12 on: November 28, 2002, 03:27:00 AM »
i recommend you check the security demonstrations
at the local university. you'll reconsider some of
your opinions. i'd rather wait some weeks for the
rb to arrive than risk an implosion...

Moriarty

  • Guest
I'm talking too much!
« Reply #13 on: November 28, 2002, 11:38:00 AM »
Sorry but I had to say something.  I don't think that was the point.  Will it implode?  Probably not.  Is the risk greater?  For sure.  Anyway, the truth of the matter  is that glass under goes wear and tear (sp?), probably at the bottom of the flask more than any other place where flat glass is most volnerable.  All glass is made differently by the glass companies and their varying standards, respectively.  Dare I say, and I don't know this, each piece they produce it different in some way.  There are no specs that could insure this man's safety.

Just get thick walled round bottomed flasks.  They are designed for a strong vacuum.

The issue here is what is more likely to leave this bee without a hospital visit.  I've experienced some real lab accidents in the 12 years of off and on (mostly off) experimentation and the most unlikely things happen.  Just do that which is more suited to your safety.  pHarmacist is probably right.  Nothing would most likely happen but FUCK!!!  It's so cheap to do it right with regards to your own personal safety.  You won't hear another word from me.  I just don't see the point in defending flat glass.  Maybe I missed the point.  I'm not picking on you, and might not even understand the issue as well as you do, but it's widely accepted that RBF's are preferred for the very reasons discussed in this thread.

Who wants to play cops and dope fiends?

Chromic

  • Guest
A few more numbers
« Reply #14 on: November 28, 2002, 11:59:00 AM »
The flat surface on a small flask is about one inch squared. That's 14.7lb of pressure (1atm = 14.7 psi) that is unequally distributed on the small flask. That's not too bad. But if you double diameter of the flat surface you've now got 4x the pressure unequally distributed over that area, with a larger volume whose wall thickness has not proportionally increased, combined with heat, with any surface imperfections... your flask stand a good chance of imploding.

Moral of the story, no one likes to clean up spilled safrole... so don't risk it.

raffike

  • Guest
I know RB's are way to go with vacuum but what if ...
« Reply #15 on: November 28, 2002, 12:03:00 PM »
I know RB's are way to go with vacuum but what if i have 12 liter RB,is it ok to attach vac to so large RB(for distilling the last part of water out when makin methylamine)?

A friend with speed is a friend indeed

Osmium

  • Guest
This shit has been discussed ad nauseum in the ...
« Reply #16 on: November 29, 2002, 04:29:00 AM »
This shit has been discussed ad nauseum in the past, and the conclusions were always the same!
Being the swell guy that I am, I'm gonna give you some top secret information: we even have a pimp as fuck toolbox to retrieve all that stuff!
Here it is!

https://www.the-hive.ws/forum/searchx.pl?Cat=



You will be able to find all kinds of cool stuff there. So please keep it to yourself, do not share this source with anyone!

Oh yeah, almost forgot to give you some free search results regarding the stupidity of using flat bottomed glassware! Here it is!

Post 89079 (missing)

(bliss: "flat versus round bottom flasks", Chemicals & Equipment)

Post 104748 (missing)

(Somaz: "Flat-bottomed flasks under vacuum?", Chemistry Discourse)

Post 198900 (missing)

(reflux: "vac bomb", Newbee Forum)

Post 305676 (missing)

(chem_123: "Sass. distillation setup", Newbee Forum)
and many more

I'm not fat just horizontally disproportionate.