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Author: Subject: Ground Joint Soda Glassware
Sulaiman
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[*] posted on 20-1-2018 at 07:26
Ground Joint Soda Glassware


Two days ago I ordered a couple of small glassware parts via eBay and I just looked at them again,
one item now looks like I should have read the description more carefully
https://www.ebay.co.uk/itm/14mm-Female-to-18mm-Male-Expander...:DfsAAOSwhpZaQKN0
as it seems that the glassware is intended for some kind of drug taking pipe, so is only made of soda lime glass.
If my suspicion is true then using this with my borosilicate kit could be a false economy :(

Any opinions as to whether this piece is borosilicate or not ?




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JJay
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[*] posted on 20-1-2018 at 07:58


It's probably borosilicate, but I wouldn't use one of those with labware. When I see drug paraphernalia listed with the labware on eBay, I report it if it clogs up the search listings. Sometimes I send a scathing diatribe to the seller.



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unionised
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[*] posted on 20-1-2018 at 08:06


This sort of thing might help.
https://www.exploratorium.edu/snacks/disappearing-glass-rods
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LearnedAmateur
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[*] posted on 20-1-2018 at 12:35


Yeah they’re for bongs/water pipes (sorry if I’m not supposed to use those terms here), I wouldn’t class it as drug paraphernalia in itself but 14.5 and 18.8mm are the two joint sizes typically used for this purpose. Since the adapters aren’t directly heated, and considering the cost, I’d go with it being soda lime.

I’d purchased a $0.99 14/23 male-male adapter for use in chemistry, for a cheapskate Dean-Stark setup in the synthesis of p-toluenesulphonic acid, and it does the job just fine for a fraction of the cost of purpose made glassware. The trade off being that the joints aren’t overly precise and tend to wobble, being about 1-2mm out, so if you’re concerned with leaking gases then it’s probably best to avoid it and just spend out a little more for the borosilicate options.




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Dr.Bob
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[*] posted on 20-1-2018 at 14:59


Not sure what use this would even have for real lab glassware, since it's hard to tell if the joints are standard tapers. Maybe it would work for 14/22 and 19/22, but not at all clear. There are other Chinese vendors with real lab glass for not much more, I would stick to the better stuff, only a small difference in price.
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LearnedAmateur
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[*] posted on 20-1-2018 at 22:21


Quote: Originally posted by Dr.Bob  
Not sure what use this would even have for real lab glassware, since it's hard to tell if the joints are standard tapers. Maybe it would work for 14/22 and 19/22, but not at all clear.


Yes they use the standard tapers, I’d also bought a cheapie 14.5-18.8 adapter, just the other way around to the one in question since I had a small job lot of 19/23 RBFs. The only variations being, IME, the length of the joint so it could either protrude past or stop before the connecting joint terminates on the fused end. Regarding the last point however, I’ve had this occur with purpose built QuickFit glassware, the most prominent one being between a sintered glass funnel and a 24/29-14/23 adapter (somewhere in the range of 5-10mm), so it’s not a big issue unless a perfect fit is absolutely required.




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Sulaiman
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[*] posted on 21-1-2018 at 02:15


Even though I can't resist cheap stuff, I assumed that the adapter was borosilicate when I ordered it,
I'll do the glycerol refractive index check (thanks unionised)
... if not borosilicate then I'll bin it to avoid future problems.

I just wanted an opinion on the glass type
and to warn others of the potential problem
as this is the first time I've come accross non-borosilicate ground joint technical glassware.




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NEMO-Chemistry
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[*] posted on 22-1-2018 at 17:16


Quote: Originally posted by Sulaiman  
Even though I can't resist cheap stuff, I assumed that the adapter was borosilicate when I ordered it,
I'll do the glycerol refractive index check (thanks unionised)
... if not borosilicate then I'll bin it to avoid future problems.

I just wanted an opinion on the glass type
and to warn others of the potential problem
as this is the first time I've come accross non-borosilicate ground joint technical glassware.


I also got some of these recently. they freeze up lab glass joints really easy.

The ground finish on mine was very bad
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Sulaiman
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[*] posted on 6-2-2018 at 08:23


The adapter arrived today,
I put it in a beaker together with vegetable oil and a GG17 (borosilicate) adapter,
both adapters 'dissapeared' almost completely but not quite,
the new adapter seems to have a refractive index VERY close to borosilicate glass.




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wg48
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[*] posted on 6-2-2018 at 12:32


Quote: Originally posted by Sulaiman  
The adapter arrived today,
I put it in a beaker together with vegetable oil and a GG17 (borosilicate) adapter,
both adapters 'dissapeared' almost completely but not quite,
the new adapter seems to have a refractive index VERY close to borosilicate glass.


I suggest you also put soda glass in as a comparision.

You may also be interested in this:

Another scheme which works is to make up a solvent solution (16 parts of methanol and 84 parts of benzene) which has a refractive index of 1.474. Borosilicate glass has the same index value.

from: A Simple Method of Distinguishing Borosilicate and Soda Lime Glass pubs.acs.org/doi/pdf/10.1021/ed056p692 by WH Brown - ‎1979
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[*] posted on 12-2-2019 at 21:58


All bongs and glass smokeware are pyrex.sodalime glass would crack when heated and cooled.it is definitely borosilicate.its the same glass your flasks are made of.
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