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PhenethylamineMachine
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To the original poster: have you not worked with any of this laboratory equipment previously?
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fusso
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@Pheneth...
I havent worked with them before, I just worked with basic beakers, test tubes, conical falsks etc, but definitely havent with those with glass joints
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Texium
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I use both 14/20 and 24/40. I started out with 24/40 because that's what I was able to get my hands on out of luck, originally, but looking back, it
would have been easier to start out with 14/20. I use both types about equally now, but it's advisable to start small.
19/22 is an awkward joint size, in my opinion, and I wouldn't recommend it. While it can be seen as a happy medium for amateur scale work, it seems to
be mainly used in teaching labs. Thus it's hard to find more specialized glassware in that size that you wouldn't normally find in an organic teaching
lab kit. The research lab that I work in uses only 14/20 and 24/40 pieces like I do at home. Adapters that convert from 14/20 to 24/40 are common too
if you ever need to bridge the gap for any reason.
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Leafs
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I went with 24/29.
Sidenote question though for anyone.
I know that 24/29 male joint will fit inside a 24/40 female joint, but will 24/40 male (like a condenser) fit inside a 24/29 female (flask)? Don't
think it would be ideal though from an efficiency standpoint having some of the joint hanging inside like that.
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Melgar
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Yeah, both "24" sizes fit together both ways. It's just that they only touch each other for 29 mm of their length.
Personally, I started with 24/40 because it's easier to find. But then I realized that my mistakes tended to do a lot less damage when I'd experiment
at smaller scales, and eventually put together a 14/20 set. It's also allowed me to experiment without using up as much in the way of reagents.
The only annoying part here is that often I need to distill a fairly large amount of liquid, which isn't practical using 14/20 gear; the largest
flasks they make are maybe 250 mL and even those are rare. It also seems like it's practically impossible to find flat-bottom flasks in 14/20, and I
don't always want or need some sort of bath for heating my flask, or feel like messing around with setting up a stand and clamps. So for that, I just
use a 24/40 flat-bottom flask, and then have a 14/20 adapter that I use with it. It means that distillations take a bit longer, but I can always get
a 24/40 condenser if that becomes a problem.
A really nice benefit of 14/20 glassware is that due to the cube-square law regarding material strength, it's much less common to accidentally break
14/20 glassware by dropping it from about the height of a table. Virtually impossible NOT to break 24/40 glass.
Oh yeah, I also think those 14/20 all-in-one distillation head contraptions look really cool, and own perhaps three. None of the really complicated
ones, but still, being able to have a one-piece distillation head is pretty convenient.
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
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Magpie
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I like 19/22 because that is the scale (50-100g) that I normally work in. If I need to go largerto make reagents I use adapters to 24/40.
I have a hood that is 4' wide. The 19/22 setups fit much better than the 24/40, both for width and height.
The single most important condition for a successful synthesis is good mixing - Nicodem
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LearnedAmateur
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Quote: Originally posted by Melgar  | | A really nice benefit of 14/20 glassware is that due to the cube-square law regarding material strength, it's much less common to accidentally break
14/20 glassware by dropping it from about the height of a table. Virtually impossible NOT to break 24/40 glass. |
And 19/26 it seems, my poor 250mL RBF just suffered an incurable star fracture from a 5cm drop onto the base of my retort stand. I was just getting
back into experimenting as well just to take the piss, the hydrolysis of APAP then a Sandmeyer reaction to hydroquinone - luckily I saw it before I
hit the thing with a flame! ‘Tis a sad day, but oh well, time to go shopping and this time I’ll try find a 14/23.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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fusso
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Soxhlet extractor: upper female joint size?
So I think I also need a soxhlet extractor for extractions. However I'm not sure what size should the upper female joint be. Can someone give me some
advices?
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DavidJR
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| Quote: Originally posted by LearnedAmateur |
And 19/26 it seems, my poor 250mL RBF just suffered an incurable star fracture from a 5cm drop onto the base of my retort stand. I was just getting
back into experimenting as well just to take the piss, the hydrolysis of APAP then a Sandmeyer reaction to hydroquinone - luckily I saw it before I
hit the thing with a flame! ‘Tis a sad day, but oh well, time to go shopping and this time I’ll try find a 14/23. |
If you have a blowtorch then it's pretty easy to repair that sort of fracture. Just make sure to warm it up slowly, and even more importantly, to cool
it down very slowly afterwards (i.e. flame-anneal the glass).
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S.C. Wack
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Until it eventually arrives from Laboy or aliexpress. Cheap 10/30 thermometers are harder. There's one on ebay for $11, only $26 shipping.
| Quote: Originally posted by fusso | | So I think I also need a soxhlet extractor for extractions. However I'm not sure what size should the upper female joint be. Can someone give me some
advices? |
It depends on scale. I love glass extraction thimbles for them and never have found a cheap source of cellulose thimbles. They're often found cheap
because no one knows what they are, but IME they tend to be just a hair too big if American or small if Chinese for Pyrex Soxhlets.
[Edited on 7-5-2018 by S.C. Wack]
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LearnedAmateur
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| Quote: Originally posted by DavidJR |
If you have a blowtorch then it's pretty easy to repair that sort of fracture. Just make sure to warm it up slowly, and even more importantly, to cool
it down very slowly afterwards (i.e. flame-anneal the glass). |
Yeah, but nah, the number of times I thought I could get away with that just to end up with a pile of glass shards because one of the cracks shoots
around the piece making the problem even worse. I do try to heat outside the crack then slowly move in to limit propagation but it’ll fuse then
slowly creep back and wham, I’ve got two bits when there should only be one. I’ll just stick to using it as a low temperature vessel rather than
risk it going in the bin, maybe I’ll give it a go if I have access to a MAPP torch in the future but my little torch won’t be able to fix that.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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DavidJR
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| Quote: Originally posted by LearnedAmateur |
Yeah, but nah, the number of times I thought I could get away with that just to end up with a pile of glass shards because one of the cracks shoots
around the piece making the problem even worse. I do try to heat outside the crack then slowly move in to limit propagation but it’ll fuse then
slowly creep back and wham, I’ve got two bits when there should only be one. I’ll just stick to using it as a low temperature vessel rather than
risk it going in the bin, maybe I’ll give it a go if I have access to a MAPP torch in the future but my little torch won’t be able to fix that.
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I've had success just using my el-cheapo eBay butane torch (only issue with that torch is that it occasionally emits flames from orifices which are
not supposed to emit flames). Then again plenty of times i've tried to repair glassware and it's gone very wrong, but given that it was broken anyway,
I don't consider it much of a loss if I break it even more.
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sodium_stearate
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I'd like to see some pictures of some of the repaired
glassware! That sounds very interesting about being
able to make repairs using a torch.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
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DavidJR
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| Quote: Originally posted by sodium_stearate | I'd like to see some pictures of some of the repaired
glassware! That sounds very interesting about being
able to make repairs using a torch. |
I had a RBF star fracture very similar to the pic posted by LearnedAmateur. It was either a 250ml or 500ml flask, don't remember. I've looked closely
at all of my flasks and honestly I can't figure out which one it was. Maybe if I looked at them with a polariscope...
I've never had good results trying to repair glassware which has actually separated into multiple pieces. However, if it's cracked but still in one
piece, then it's not too difficult.
You need to heat it up slowly and evenly or the crack will propagate further. Start with a small flame and keep it moving over a large area
surrounding the crack.
As the area surrounding the crack heats up, you can turn up the torch and focus on a smaller area, while still keeping the flame moving. It'll
eventually glow a dull red/orange and you can then blast the crack with lots of heat without moving the flame much. You will suddenly see the crack
join back together and become more transparent (like the difference between a greased and ungreased joint). Continue heating strongly for a few
minutes to ensure a good repair.
Then very slowly cool the piece, using a gradually reducing size of flame/increasing distance, again constantly moving flame. If you cool it too
quickly, the glass will be weak due to stresses trapped in it.
Disclaimer: I'm no glassblower so take this advice with a grain of salt.
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Dr.Bob
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| Quote: Originally posted by fusso | | So I think I also need a soxhlet extractor for extractions. However I'm not sure what size should the upper female joint be. Can someone give me some
advices? |
It is about volume of liquid you want to extract with. There are small, medium, large, and huge. The small only holds 30-40 ml in the top
extractor, medium is maybe 50-60 ml, and large is over 100 ml. The amount of solvent needed in total is about triple that. I would tend to stick
with medium as a starting point unless you know what scale you are considering.
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fusso
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| Quote: Originally posted by Dr.Bob | | Quote: Originally posted by fusso | | So I think I also need a soxhlet extractor for extractions. However I'm not sure what size should the upper female joint be. Can someone give me some
advices? |
It is about volume of liquid you want to extract with. There are small, medium, large, and huge. The small only holds 30-40 ml in the top
extractor, medium is maybe 50-60 ml, and large is over 100 ml. The amount of solvent needed in total is about triple that. I would tend to stick
with medium as a starting point unless you know what scale you are considering. |
What's the corresponding female joint size above the thimble?
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Texium
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The smallest Soxhlet I've seen has a 34/45 joint. 45/50, 50/50, and 55/50 are typical for medium-large ones. Bigger than that and you get some other
wonky large joint sizes going as big as 80 or 90 mm.
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S.C. Wack
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Download and read the catalog from Ace Glass. It's a great reference. Like that Soxhlet on ebay I turned down with the 55/50 base because where am I
ever going to find a used condenser for it. Turns out all I needed was a little reducing adapter.
[Edited on 7-5-2018 by S.C. Wack]
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Dr.Bob
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small, cond is 34/45
med, cond is 45/50
large, cond is 55/50
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S.C. Wack
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| Quote: Originally posted by S.C. Wack |
Until it eventually arrives from Laboy or aliexpress. Cheap 10/30 thermometers are harder. There's one on ebay for $11, only $26 shipping.
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A BTW update after trying aliexpress I see why that store has filled like 5 orders even though they're so cheap. They took my information but refused
me in the end and locked my account.
No problems with Laboy except it costs more and there's some things I wanted, especially gas dispersion that Laboy doesn't offer. They sell 10/18
thermometers but these seem to fit 10/30 better and appear to be closer to 10/21. So I'd recommend them for "10/30" thermometers except they're pricey
for the quality, have the usual faint scale, and one has to take their word for it on the immersion, because there is no line and no writing.
[Edited on 16-7-2018 by S.C. Wack]
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zed
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Umm. Deschem and Nanshin, have online E-bay stores, that you can peruse as required.
Lots of Soxhlets, adapters, and friendly prices.
Larger neck provides easier access, and the capacity to accept larger diameter items.
https://www.ebay.com/sch/m.html?_ssn=deschem&_from=R40&a...
[Edited on 16-7-2018 by zed]
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S.C. Wack
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A larger neck Soxhlet, the one I was referring to with the 55/50 base and should have bid high on, are the Ace 6810's. 500-5000 ml. Brilliant finding
24/40 on ebay...unfortunately neither of them sell 19/22 except for an adapter to 24/40. Laboy sells some weird things including 19/22; in theory the
anything store on aliexpress had a lot more, at prices too good to be true.
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