Acetic Acid
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Homeblown retort
Hm... so you know those glass watering globes for plants? Well I got 6 of them for $5 and attempted to blow one into a retort. I chose to start with
the crappiest one that was small and had a really short and wide stem. Using a torch I managed to bend it into the proper shape. By keeping it
slightly above the flame I managed to cool it without it breaking, but when it WAS cool it cracked slightly. It made a few more small cracks for
unclear reasons. I loaded it with vinegar and noticed that there was no leak through the cracks, so I thought it would be alright. I set it up for
steam distillation. The water got to full boil and the vinegar was about to begin distilling, but then there was a problem. The assembly didn't
shatter, but rather the stem gently came loose at the cracks. I'm going to try it again tomorrow after homework, with a better and longer globe. Wish
me luck!
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Acetic Acid
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Questions: What's a REALLY easy substance to distill? You know, so I can see if this thing works
Do you think I could use epoxy to seal up those tiny cracks if/when they appear on my next attempt?
What is the composition of the decorative blue junk on the globe? Just colored glass?
[Edited on 8-9-2011 by Acetic Acid]
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bob800
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Quote: Originally posted by Acetic Acid  | Questions: What's a REALLY easy substance to distill? You know, so I can see if this thing works
[Edited on 8-9-2011 by Acetic Acid] |
Water... Do you mean something with a low boiling point? In that case, something like alcohol would obviously distill at a lower boiling point, but
PLEASE DO NOT DISTILL ANYTHING HAZARDOUS IN YOUR SETUP.
Cracks in chemical glassware don't just make things leak. They can often cause articles of glass to shatter when heated, spewing your chemicals
everywhere. If you distilled anything flammable, I think you can guess what may very well happen. 
Try blowing another retort, but this time try to cool the temperature slowly. IIRC, if using a bunsen burner, you can close the air-intake to produce
a relatively cool, sooty flame. This is useful to slowly cool and "anneal" the glass. After you've "cooled" the glass to this temp., submerge your
retort in a bin of vermiculite or similar non-flammable insulator. Cotton will work but will probably smolder and possibly ignite.
Leave it in the insulation until cool. I still wouldn't recommend this for hazardous procedures like nitric acid distillation, however.
NEVER USE CRACKED GLASSWARE!! (Even if you plug it with epoxy)
[Edited on 8-9-2011 by bob800]
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Acetic Acid
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ok thank you. I encountered slight problems loading the retort, even through the globe with the fat stem. Any idea how to get something into the
(tiny) opening of the stem?
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Panache
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wool is good or when using the bunsen on sooty flame at the end do this for a very long time like 10 minutes, the purpose is to cool it slowly in
something less hot but still hot. Glass i a pathetic conducter of heat and cools poorly, thats why it takes a long time.
Then immediately put the very very sooty retort into your kitchen oven that has been preheated at its highest temp possible and close the door and
turn it off. leaving the item in there until it is at room temperature and not opening the door.
This will give you your best chance.
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vr6t4dr
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fiberglass insulation
a long time ago....beer/wine/liquor bottles used to be turned into water pipes. for smoking and whatnot. anyways. right after your done, wrap it in a
piece of fiberglass insulation. we also used to set that in the oven on warm then turn off, so it will cool slower. just a tip if it helps...
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fledarmus
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This is a problem, especially if the glass is not particularly uniform either in thickness or in composition. Heating small areas of glass and
reforming them, then allowing them to cool, will set up stresses throughout the glass. Additional stresses occur as thinner areas cool and shrink
quicker than thicker areas. Pyrex, due to its composition, expands and shrinks less during heating and cooling, and is less likely to develop these
stresses. Any of these stresses can develop into cracks, and once you have cracks in your glassware, you are asking for trouble if you try to use it.
Annealing ovens are the best way to handle the stresses. They heat the glass up hot enough to allow the stresses to be relieved without melting the
glass, then cool it slowly so they do not redevelop. If your glass is reasonably uniform in thickness, you can get a similar effect by heating a much
larger area of the glass while you are working it, and then heating the entire piece with a broad, feathery flame after you are finished and
insulating it while it cools.
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Neil
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... http://library.sciencemadness.org/library/books/GlassWorking... ...
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Endimion17
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What kind of glass are these globes you're talking about? Anything other than borosilicate (or quartz) glass shouldn't be heated.
If you really want to make a retort, you have to anneal it like fledarmus told you. Use sooty, safety flame and cover the whole heated area in soot.
Then you can bury it in asbestos dust if you're extra careful and doing it outside. 
When the stuff cools down, wipe the soot and inspect the glass using polarizing filters (search for photoelasticity). If there's any stress, this is how it will look like. The more contrast, the greater the chance it will burst. Yeah, it can even explode in rare cases, but it usually
bursts or breaks.
Never ever heat glass vessels in direct flame, especially if there's something flammable inside. Use sand baths for retorts. People get the wrong idea
that retorts are (and were, by alchemists) heated in flame. Usual stupid picture is a retort with an alcohol burner underneath. Bullshit. That kind of
localized heating is the most dangerous.
Alchemists were putting them in furnaces with glowing coal and ash. That ensured uniform heating. But they had lots of accidents with cracking glass
because they didn't have borosilicate one.
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Bot0nist
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A good practice run would be to distill of some pure water from brine (saturated NaCl solution) and test it for saltiness to rule out carry over. You
could also salt a little white wine and attempt to distill a fraction of ethyl alcohol from it. The alcohol could be tested by seeing if it will burn
at room temp. Using beer and red wine wont work as well, as they tend to foam up a lot.
Use a "frydaddy" or a pan on an electric burner or hotplate filled with oil as your heat source. This will greatly reduce a chance of ignition,
provide an even heat to the apparatus, and most oils can reach temperatures suitable to boil water and many other volatile liquids before nearing
there(oils) smoke point.
Be careful before thinking of trying to distill dangerous things like HNO<sub>3</sub> or other acids in these though. Even something like
diethyl ether could be potentially catastrophic if your apparatus fails.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Mildronate
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You need heat your retort in tube furnance after making it, because there is glass stress.
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Acetic Acid
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Update: on my 4th attempt I managed to cool one to room temperature without it cracking. I decided to epoxy the hell out of the joint to lower the
chance of me accidentally breaking it with force. I loaded the retort with saturated saltwater (easier said than done through the small stem) and put
the globe over a 250 ml beaker filled with water. I heated my hotplate to around 200C in an attempt to do a steam distillation. I couldn't get the
saltwater to boil, presumably because of boiling point elevation from the dissolved salt. The globe didn't shatter when I turned off the hotplate and
let the assembly cool. The next thing to do is to try a sand bath or oil bath, which I know will get to the right temperature.
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Bot0nist
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Use an oil bath @ ~150C to distill the water.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Acetic Acid
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What kind of oil do I use? Would pharmacy-bought mineral oil work?
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Bot0nist
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I guess, I use canola or Crisco a lot.
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Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Acetic Acid
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Can the oil be re-used for multiple distillations? Roughly what temperature does it go up to?
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Bot0nist
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Yes, it depends on the smoke point if the oil. Just Google the particular oil to see.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Acetic Acid
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Thanks for your help.
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Bot0nist
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No problem. Remember that your oil bath needs to be at least 20c hotter than the boiling point of your target fraction because of the heat that is
lost as it transfers from your heatbath to your solutions in the apparatus. This is why you can't boil brine with a fresh water bath. Using brine as
your heating bath will work when distilling low boiling point fractions like ether and IPA/ethyl alcohol.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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mr.crow
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Don't waste your time
Your crappy home made retort WILL break and your oil bath will explode everywhere
Double, double toil and trouble; Fire burn, and caldron bubble
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Bot0nist
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Yeah, I forgot to add, wear eye protection (face shield) when trying this. You know what happens if a liquid that boils at 75C falls into an oil bath
of 150C right?
[Edited on 11-9-2011 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Acetic Acid
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This is the type of failtastic overly concerned post I really hate on these forums. I get it if someone is talking about making F2 or some illegal
drug, but really? This isn't ScienceForums. These boards are supposed to be about mad scientists doing mad experiments, not a bunch of numptys going
"nooooooo dont do it its 2 dangerus" like the other boards I've seen...
On a related, more polite note, yeah of course I wear a full face shield. I have no plans to do any dangerous distills and I'm ready for the thing to
shatter at any moment, even though it already made the cooldown from when I initially made it. Also, what makes up the blue/green decorative junk on
the outside of the glass? I'm certain it won't interfere with my distillations but I like to be able to see through the thing clearly. 
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dann2
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The thinner the walls of the retort the less liable it will be to crack due to internal stresses in the glass.
Every time I see a large light bulb, I see a round bottomed flask........
Dann2
[Edited on 12-9-2011 by dann2]
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Endimion17
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| Quote: Originally posted by dann2 |
The thinner the walls of the retort the less liable it will be to crack due to internal stresses in the glass.
Every time I see a large light bulb, I see a round bottomed flask........
Dann2
[Edited on 12-9-2011 by dann2] |
Not necessarily. Thin walls will be less liable to create internal stresses, whereas thick walls will. Though the thick walls are stronger.
It's not a good idea to judge the crack resistance by the thickness of the glass. It's best to check for photoelastic stresses and to know what type
of glass is it.
@Acetic Acid: Though I don't appreciate some kinds of sarcasms and I understand your frustration, the advice was not that bad.
I don't really recommend oil bath at 150 °C for heating water in a retort prone to cracking. Goggles won't save you. This can happen. Use a sand bath instead.
And buy some large, thick test tubes. They're made out of borosilicate glass, so you can turn few of them into (usually) dispensable retort which
won't crack that easy.
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mr.crow
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| Quote: Originally posted by Acetic Acid |
This is the type of failtastic overly concerned post I really hate on these forums. I get it if someone is talking about making F2 or some illegal
drug, but really? This isn't ScienceForums. These boards are supposed to be about mad scientists doing mad experiments, not a bunch of numptys going
"nooooooo dont do it its 2 dangerus" like the other boards I've seen...
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Yes, I shouldn't have been rude. Sorry. I also missed the purpose of your experiment
Double, double toil and trouble; Fire burn, and caldron bubble
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