Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
24/40, 24/29, 29/32, what is the best?
Goodmorning everyone 
I am thinking of renovating my ancient laboratory, and I am undecided which glassware kit to buy.
In particular, my problem is choosing the best type of joint, but I don't know what practical differences exist between them.
For example, between 24/40 and 24/29, which one to choose?
And why are there so many types that are very similar in diameter to each other?
Thank you all
PS: The kit I would like to purchase would probably be this (the price seems good to me, less than 200$,some other advice is welcome):
[Edited on 28-3-2021 by Blunotte]
|
|
|
Antigua
Hazard to Others
Posts: 155
Registered: 27-9-2020
Member Is Offline
|
|
Generally, 24/29 and 24/40 are considered "american". These are the most used standards in Chinese glass too. So if you aim to buy all/most of your
glass from Chinese suppliers, then these are the way to go. 24/40's joint lenght is larger than 24/29's but they're compatibile with each other. I
wouldn't say that either of them are superior really, the 29 milimeters of joint surface is more than enough to keep a seal. So whatever is more
available and cheaper for you. 29/32 is more of an European standard (at least in Eastern Europe it's commonly used) and may be harder to get on Ali
or eBay. So pretty much it comes down to availability! Keep in mind that 29 is a bit larger than 24.
|
|
|
Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
Hi Antigua, thanks for the explanation:
In fact, all the glassware I currently have is 29/32 (I mostly have a lot of round bottom flasks), but I see it's hard to find, so I thought about a
total refurb, rather than additions.
So if I bought the 24/40, it would then be compatible with a future 24/29, great to know, thanks, I think this will be the path I will choose
|
|
|
Antigua
Hazard to Others
Posts: 155
Registered: 27-9-2020
Member Is Offline
|
|
I highly advise you to get some 24 to 29 and 29 to 24 adapters. They are very cheap and they solve any joint problems one might have. I once bought a
set of adapters from 14 to 29 and never had to worry whether the flasks I have are the right joint sizes.
|
|
|
Texium
Administrator
Posts: 4618
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Historically, 24/40 has been more common in America while 24/29 is more common in Europe. Likewise, for 29 mm joints, 29/42 is seen more commonly in
America while you'll see 29/32 in Europe. Nowadays though with glassware widely available online and rarely purchased locally, it isn't especially
relevant which one you go with. I would recommend going with 24 mm though, whether you choose 24/40 or 24/29. 29 mm glassware is less commonly
available in general, and there tends to be less variety of it available. For instance, you can easily find 29/xx flasks, but you might struggle to
find a Dean-Stark trap. Also, 29/xx flasks tend to have a lower limit of about 250 mL, especially for multi-neck flasks, whereas 24/xx flasks can be
found easily as small as 50 mL. Unless you want to work on multi-liter scale all the time, 24/xx will cover everything you need to do.
Another thing worth considering is 14 mm. Available in 14/20 (US) or 14/23 (international), which are also cross-compatible, it is a very versatile
size for glassware as well. Single and multi-necked flasks are readily available up to 500 mL and most everything that you can find in 24/xx can be
found in 14/xx as well. It's good to have a 14/xx kit because when working with smaller scales, using 24/xx glassware can lead to heavy mechanical
losses. 14/xx glassware is generally less expensive too. I actually use 14/20 for most stuff, and only break out the 24/40 for stuff where a large
volume is required, like steam distillation, or bulk preparation of nitric acid.
|
|
|
metalresearcher
National Hazard
Posts: 758
Registered: 7-9-2010
Member Is Offline
Mood: Reactive
|
|
I also have mostly 29/32 glassware, does that mean I cannot use 24/40 ?
|
|
|
Dr.Bob
International Hazard
Posts: 2750
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: No Mood
|
|
It also depends on where you are. If in the US, 24/40 is the most common, although I have lots of 29/42 stuff for sale, if you are in the US.
Outside of the US, there are other sizes that may be more common.
|
|
|
Sulaiman
International Hazard
Posts: 3721
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
Random ramblings...
. https://en.wikipedia.org/wiki/Ground_glass_joint
. There is no glassware size that satisfies all needs
sometimes smaller is better, other times I want much larger.
. Glassware size tends to influence
- hazard per experiment/procedure
- cost; heating, stirring, cooling, filtering....
- required workspace area
- quantity of chemicals purchased (e.g. 100ml vs 500ml vs 5l)
- storage space for chemicals
- safety of chemical storage (small spill or fire vs large one)
- quantity of waste to deal with.
Due to cost I have bought mostly new Chinese glassware and used quickfit.
If you can afford it, glassware with good joints is very nice to use.
Chinese glassware is very capable but...
It seems that 24/40 still gives the most options on eBay etc.
(most of my stuff is 24/29)
PS Lately I have specifically chosen GG17 glass if from China - it looks and feels good
- time will tell..
[Edited on 29-3-2021 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Fyndium
International Hazard
Posts: 1192
Registered: 12-7-2020
Location: Not in USA
Member Is Offline
|
|
One useful info first:
- 29/32 and 29/42 are usually always interchangeable. Only some very tight angles could cause issues fitting 42 male into 32 female, but I never had
this issue with any combination.
- 24/29 and 24/40 are usually also always interchangeable. Same as above.
- Most everything can be fitted with adapters. I have 29* glassware from older ages, and new 24* glassware, and a bag of adapters m29>f24 and
f29>m24 to fit all together. Issue with adapters is that equipment height can rise quickly and may not fit in your fume hood or workspace and it
also causes more torque stress so a little more care must be taken when mounting clamps.
In eBay at least, 24* seem to have the widest and cheapest selection of glassware, so I would go with that. You can freely upgrade and downgrade from
minor to major size and get all the equipment. I would suggest this size to all amateurs and general chemistry. Larger joint sizes come handy when
upping glassware size to something like +5 liters.
If you need and intend to make only small experiments, smaller joint size like 14* could provide useful. Mechanical losses from large equipment go up
quickly - try distilling few mL of liquid in 29/32 glassware, and you might end up nothing useful.
Those kits are good bang for buck usually. Just maybe hit an extra fritted funnel there, a stirmantle/plate and lab jack and 4-6 clamps and bossheads
and you're good to go. If you're willing to invest half k$ at start, you'll get pretty much all equipment you need for a long time, instead of
constantly ordering little parcels here and there, like I do. 
|
|
|
Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
Goodmorning everyone
Finally the glassware has arrived (perfect packaging), and this is my first setup: distillation of denaturated alcohol at 99°.
Everything works fine, now I'll try to start using it
PS: I know, the heating mantle is not the best, and the Liebig had to be turned with the tubes upwards, and the receiving balloon had to be connected
via the dripper, but I only took a picture at the beginning, when I quickly assembled everything
[Edited on 8-5-2021 by Blunotte]
|
|
|
Texium
Administrator
Posts: 4618
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Oooo bad bad bad... you’re heating a closed system! You need to include some way for pressure to escape, either by using an open vacuum take-off
adapter between the condenser and the receiving flask, or by removing one of the stoppers that you have in the receiving flask (I’m guessing that
one probably removed itself, or the apparatus popped open somewhere else during the distillation). Don’t worry, I made the exact same mistake on my
first distillation.
|
|
|
Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
Hi Texium, I don't know if you can see from the image, but one of the two caps of the receiving balloon was only partially inserted, just to avoid
overpressure (I made this mistake years ago and I immediately regretted it )
|
|
|
Keras
National Hazard
Posts: 931
Registered: 20-8-2018
Location: (48, 2)
Member Is Online
|
|
Whoops [redacted]
I use CN19 Rodaviss glassware. Just to mention alternatives exist
[Edited on 8-5-2021 by Keras]
|
|
|
Texium
Administrator
Posts: 4618
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Quote: Originally posted by Blunotte  | | Hi Texium, I don't know if you can see from the image, but one of the two caps of the receiving balloon was only partially inserted, just to avoid
overpressure (I made this mistake years ago and I immediately regretted it )
|
Ah, no, I couldn’t see that in the picture you posted, but that’s good
|
|
|
Keras
National Hazard
Posts: 931
Registered: 20-8-2018
Location: (48, 2)
Member Is Online
|
|
This is anyway loosely stoppered. When you distill, you want to use Keck clips and grease to make sure your joints are sealed. Especially if you
distill something that could solidify on the ground glass surfaces.
That’s the Rodaviss system main advantage: no clips, no need for grease, and it’s sealed with teflon-like rugged rubber joints. It’s more
expensive, though.
|
|
|
Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
Rodaviss system is very nice, but I never found them on Internet at rasonable prices... 
|
|
|
Keras
National Hazard
Posts: 931
Registered: 20-8-2018
Location: (48, 2)
Member Is Online
|
|
It’s not that expensive, but Chinese manufacturers don’t use it, I think the system is patented. My glassblower claims a single CN19 rugged
Rodaviss joint costs him € 7.
It’s more frequent in Europe, I guess? Anyway, it’s a nice standard.
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
A drying tube with CaCl2 or just cotton would be preferable.
|
|
|
pneumatician
Hazard to Others
Posts: 412
Registered: 27-5-2013
Location: Magonia
Member Is Offline
Mood: ■■■■■■■■■■ INRI ■■■■■■■■■■ ** Igne Natura Renovatur Integra **
|
|
oh, I want to buy one like this of 3L for occasional use, no problem heating the flask, all ok, heat around the flask?
In my experience: 24/40 (usa standar) for low volumes, no more than 2L, I've one of 10L as is near impossible to clean with brushes.
From here the more volume and solid the matter, the wider the mouth, but if is only for a repetitive use for some easy liquid to clean like alcohol...
14/23 for low volumes, 5-100ml, 29/32 is a european standar, 24/29 aussie and chinese standar?... so it depends of what and how many. In the end you
have a pouporri of joints and adapters or a mega lot of glassware :-)
Sometimes the matter after distil. is so hard and indisoluble... or you search info before or use a reactor or if yuo want to recover what remain
inside the flask your only option is offer it in sacrifice :-(
[Edited on 8-5-2021 by pneumatician]
|
|
|
Blunotte
Harmless
Posts: 49
Registered: 2-4-2015
Member Is Offline
Mood: No Mood
|
|
It works perfectly, only the first few times it smells like hell and then you have to clean the RB with alcohol
For the rest, fine
|
|
|
pneumatician
Hazard to Others
Posts: 412
Registered: 27-5-2013
Location: Magonia
Member Is Offline
Mood: ■■■■■■■■■■ INRI ■■■■■■■■■■ ** Igne Natura Renovatur Integra **
|
|
oh yes, normally the manual say: put at max temp until fumes appeard, stop, when no fumes, start again until fumes and so on until no more fumes.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
