Sciencemadness Discussion Board - Ground glass joints - US to EU ISO adaptors?

Ground glass joints - US to EU ISO adaptors?

picketfence - 23-1-2007 at 05:31

Has anyone here come across any adaptors to make compatible the US standard ground glass joints to the European and australian ISO standards?

Sauron - 23-1-2007 at 06:44

I didn't know ISO was involved in this.

I am familiar with the full lenth joints, fir example 24/40 and 45/50 and have occasionally run across shorter joints such as 45/40. Some glassware catalogs show three series of standard taper joint lengths: long, medium and short.

But in all cases I have encountered these are interchangeable.

A short inner fits in a long outer.

A long inner usually fits in a short outer.

So no big deal.

So, is there something new? Something requiring an adapter?

Things get a bit more complex with spherical ball/socket joints and in this instance Buchi likes to make proprietary sizes which can be annoying when it is time to replace a nicked joint member.

Coldfinger - 23-1-2007 at 08:57

Sauron, if i am not mistaken, picketfence is asking if for example there are any adaptors that would allow a 24/29 (Australian size) condenser with a 24/40 (US Size) RBF, meaning a borosilicate piece with a 24/29 socket and 24/40 cone would be required.

If i am correct, i have seen 3 or 4 similar adaptors on ebay (australia) in the past, but none in the last 12 months or so, maybe it might be an idea to order a heap of ground glass joints from the US/EU or wherever your glassware is the standard and get a glass blower to make you up some adaptors with the local standard that you need, it isnt as expensive as you would first think

Sauron - 23-1-2007 at 09:12

What is the objection to just using the 24/29 inner joint in the 24/20 outer joint?

It fits fine but just leaves a bit of the longer taper cone exposed. You could fix that with a 24/20 PTFE liner if necessary and also avoid having to use grease.

Of course you can do as you say and have a custom adapter put together. The usual suspects (Ace, Kontes, ChemGlas, LabGlas, Schott) sell joints.

DrP - 24-1-2007 at 02:18

That's a very good idea! Build up the slack with PTFE tape and all should be well.

picketfence - 24-1-2007 at 06:44

PTFE isn't suitable for this purpose as it slips easily, I've had bad experiences with teflon-coated corks in the past.

Yeah well contacting the glass blower for custom adaptors was option two and is viable.

Coldfinger your right.

Thanks sauron and all others

DrP - 24-1-2007 at 09:30

Yes, I've suffered slippage in the past as well. The plastic clips work well for stopping this, but then your back to squre one I suppose as they are also made in set sizes.

Sauron - 24-1-2007 at 12:23

No, not teflon tape. PTFE cones.

There are full length ones that are thin, there are slightly thicker semirigid ones, there are narrow ones that are used with an applicator tool. The last are the least expensive.

The plastic clips are OK, metal clips are former, and there are two piece threaded joint clamps for both ball/socket and standard taper joint pairs, and finally there are spring loaded joint clamps with adjustable locking rings. While more commongly encounterered for ball and socket pairs they are also made for S/T.

The Keck clips are not perfect as they are subject to heat damage. They do have higher temp polymer versions but these are rarely encountered.

unionised - 24-1-2007 at 12:24

What slack?
These fittings are (AFAIK) all based on the same standard 1 in 10 taper. 24/50 means the ground part is 24mm diameter at the wide end and 50 mm long. A 24/50 cone will therefore fit into (almost) any 24/whatever socket.
If it's a 24/50 socket the 2 ground glass surfaces will be exactly the same size. If it's a 24/25 socket then half of the cone will stick into the vessel or whatever. The only problem would be if there weren't enough room in the vessel- say a short form weighing bottle.
PTFE sleeves are made precisely the purpose of fitting in between the 2 glass surfaces and you can get adaptors in PTFE too- I'd use them all the time if it weren't for the price.

itsafreecountry? - 24-1-2007 at 14:10

I'm also wondering about what disadvantage any "slack" would have. As long as the tapers are the same, would there be any procedures that forbid using a longer or shorter joint? Perhaps, say a 24/25 inner placed in a 24/40 outer may freeze more easily?

Also, this brings me to another question, is there any real purpose to a medium or short joint? Why do some product major mfrs. lines include a 29/26 or 24/25, when 29/42 and 24/40 are so common?

Sauron - 24-1-2007 at 20:05

I think I asked essentially the same question a few posts ago so I will try a partial response: in some rxns it may be disadvantageous to have ground glass exposed. Extreme example: diazomethane generation requires NO ground glass, special apparatus with ungrund joints are used to prevent possible explosions.

More commonly one might be working with materials that can permanently contaminate a ground surface and which may impact subsequent reactions (for example strong caustics.)

But most of the time you can probably get away with it, at worst you might not be advised to use that flask in some sensitive procedures later.

itsafreecountry? - 30-1-2007 at 16:15

Good point. I do remember hearing that the KOH/EtOH mixture is quite difficult to clean off.

So then what is the benefit of a 29/26 or 24/25, when if one needed to use it on their full-length stuff, the joints may become contaminated? Are these medium joints simply space-saving?

Sauron - 30-1-2007 at 21:23

I have never seen an explication of the rationale, if there was any, for the shorter series of joints. Maybe the major lab glassware companies can answer this. Ace, Corning, Schott, Kimble/Kontes.

Anybody have any insight?

It seems pretty obvious thatin principle the longer joints will provide a superior vacuum seal as long as either they are properly (that is, sparingly and at the top only) greased or used with a PTFE sleeve.

Space saving makes no sense, in a vertical stack of four joint pairs the difference between 24/40 and 24/29 is only 44mm in an assembly that could easily be a meter tall. (Fractionation setup).

chemrox - 3-2-2007 at 22:19

Are the shorter tapers compliant with another standard? I have a damned good condenser I got on ebay that has 29/26 joints. It's 500 mm with an inner coiled finger and an outer jacket. I had one like it made once and it cost a pretty but was capable of holding ten liters of boiling ether in the lower third. So with such capacity, why the short joints? And with such obvious original expense (it's also equipped with screw in water line adapters) why the shorter joints?

unionised - 4-2-2007 at 08:58

"Good point. I do remember hearing that the KOH/EtOH mixture is quite difficult to clean off."
I gather that it comes off quite easily with diprotium monoxide.
What's tricky is undoing the damage caused to the glass by the caustic.

The best explanation I can come up with for the short ground joints is that with less grinding to size they are probably easier (hence cheaper) to make,
When I'm putting glassware together in the lab I don't worry about the difference and my stuff sems to work OK.

Beatnik - 4-2-2007 at 19:10

Its not so much as they are different standards, just that as allways america likes to do things backwards. No offense but you guys have a way of complying to international standards but applying your own twist so its not entirely compatible and requires everything to be made differently.

Do you know how many textbooks i have labled, "international addition: not for sale in the US" ??? different vcr formats, etc.... prefered units of measure all that crap. All my chem lectures are prefaced with, "Any americans in here today?"

S.C. Wack - 4-2-2007 at 19:55

Why is it that we have to conform to Euro standards, but you conforming to our standards is unthinkable? Why does our glassware need to match? Why is it that you guys apply your own twist so its not entirely compatible and requires everything to be made differently?

I always find it funny how Euros (vulture comes to mind) blame amerika for all the world's problems and see it as some sort of dictator, when problems are a human condition and much dictatorshit happens in Brussels and elsewhere in the EU.

Quote:

Do you know how many textbooks i have labled, "international addition: not for sale in the US" ???

I'd worry about any textbook labelled so.

Sauron - 5-2-2007 at 10:24

All the major US lab glass companies produce short, medium, and long taper joints and will put whatever one you want on their products.

That's wht companies like Ace Glass have custom shops for.

In the era of globalization, EU glassmakers like Schott would doubtless like to enter the US market and vice versa. The US companies may have a tougher time in the EU market than Schott etc will have in the US market.

No businessman likes being poked and prodded by the ISO, nor should they?

DrP - 6-2-2007 at 02:27

Quote:

Originally posted by S.C. Wack
Why is it that we have to conform to Euro standards, but you conforming to our standards is unthinkable? Why does our glassware need to match? Why is it that you guys apply your own twist so its not entirely compatible and requires everything to be made differently?

Surley you can't be championing the worlds conversion to imperial units!!??! Us Brits changed back in the seventies to SI units for science because it is so much easier to calculate things in your head when working in base 10. Also everyone uses metric.

Anyone remember the Mars probe shambles where UK and US scientists shared some work on the project- they forgot to convert imperial units to metric or something and the thing smashed into the surface before initiating its landing sequence - it thought it was XYZ miles away, but it was actually only XYZ km away and so it crashed.

unionised - 6-2-2007 at 08:02

Close, but where are the UK scientists in this problem, Colorado or California?
"A failure to recognize and correct an error in a transfer of information between the Mars Climate Orbiter spacecraft team in Colorado and the mission navigation team in California led to the loss of the spacecraft last week, preliminary findings by NASA's Jet Propulsion Laboratory internal peer review indicate. " (Quote from NASA's site about the crash here http://mars.jpl.nasa.gov/msp98/news/mco990930.html)

This whole EU/US thing seems to me to be a storm in a teacup. All the glassware still fits because it's all 1 in 10 taper. It's all measured in mm so it's not as if it's imperial vs metric.

"Why is it that we have to conform to Euro standards, but you conforming to our standards is unthinkable?"
The simple answer to that is ecconomics; the rest of the world uses metric units so the big market is in metric stuff. Why would the EU manufacturers bother to make imperial size stuff just to sell to one country (which is a smaller market compared to the rest of the EU, nevermind the rest of the world), particularly when that country is perfectly capable of making its own stuff?
Besides which you seem to have missed a rather important point. America (specifically ANSI) is part of ISO, so those ISO standards that you seem to feel are being foisted upon you (which you have wrongly labeled as Euro standards) are every bit as American as they are, for example, English or French.

While we are on the subject, if the Americans are so detemined to use outdated English units would they please get them right. A pint is 20 ounces and a gallon is about 4,5 litres. Similarly English is the language spoken in England and, unlike American, doesn't include words like sidewalk or spellings like color. Feel free to use any words and spellings you want but don't label them as English when they are American.

End of rant; I'm off to the pub for a quick 0.000568 cubic metres

Interesting thing about SI units, if you ask most people, even most scientists, what the SI unit of weight is they will say the kilogram.
It's the Newton of course.

[Edited on 6-2-2007 by unionised]

S.C. Wack - 6-2-2007 at 16:11

Quote:

Originally posted by unionised
Besides which you seem to have missed a rather important point. America (specifically ANSI) is part of ISO, so those ISO standards that you seem to feel are being foisted upon you (which you have wrongly labeled as Euro standards) are every bit as American as they are, for example, English or French.
[Edited on 6-2-2007 by unionised]

Bullshit on your call of bullshit. US glassware is made to NIST and ASTM standards, while EURO-MADE GLASSWARE is made to EURO STANDARDS, which sure as hell isn't NIST and ASTM. Euro standards happen to be ISO standards, which although called "international", aren't.

[Edited on 7-2-2007 by S.C. Wack]

Sauron - 7-2-2007 at 04:56

Correct me if I am wrong but NIST is a government agency.
Dates from 1901, part of Commerce Department.

ASTM is a private organization.

ISO is an NGO, which means it is a pretentious private organization which would like to be santified by the UN It also is an offshoot of what is now the IEEE.

ANSI, is government or private? It's private despite calling itself a national institute, which is highly misleading, it is ninety years old and an offshoot of what is now the IEEE.

And yes very much in bed with ISO.

NOTE the only one of these with any official standing at all is NIST.

ISO is not part of the European Union government. It is a typical self promoting self serving NGO and its encroachments on national sovereignty should be regarded with due suspicion. ANSI is a creature of ISO.

I am especially dubious of ISO14000 which is their environmental standardization initiative . I bet it bodes no good for chemistry and chemists.

[Edited on 7-2-2007 by Sauron]

[Edited on 7-2-2007 by Sauron]

Sauron - 7-2-2007 at 05:48

From ISO website:

"ISO is a non-governmental organization: its members are not, as is the case in the United Nations system, delegations of national governments. Nevertheless, ISO occupies a special position between the public and private sectors. This is because, on the one hand, many of its member institutes are part of the governmental structure of their countries, or are mandated by their government. On the other hand, other members have their roots uniquely in the private sector, having been set up by national partnerships of industry associations"

unionised - 7-2-2007 at 10:04

Ho hum, Here's the list of ISO members.
http://www.iso.org/iso/en/aboutiso/isomembers/MemberList.Mem...
It seems to include ANSI as the USA's representative.
It also includes such quintessentially "European" countries as Brazil, Australia, Japan and China.

It may be a dog's breakfast of self interested busybodies but it isn't particularly European.
I also don't quite see how it's encroaching on other country's sovereignty. It has no army and isn't formally linked to any government.
The glassware still fits together.

Sauron - 7-2-2007 at 10:31

I am really concerned about Brazilian standards.

ANSI is not a government agency and despite the name is not a national institute in same sense as say NCI, NIH, NIST etc.

The sovereignty issue have to do with other issues not glassware. You are right, ISO is not "particularly European" and I said so above before you did. It is simply an NGO, no more no less. It has about as much power to coerce as say, the Boy Scouts. Maybe less.

And yes the joints do fit together.

Japan has its own JIS standards about lots of things and often tells ISO to take a hike.

unionised - 8-2-2007 at 03:16

For what it's worth, if you want to find European standards they are called "EN" rather than ISO. Of course, quite a lot of them are the same because there's no point reinventing the wheel.
BTW, Where did you say that Iso isn't European before I did. Was it here somewhere?
"
All the major US lab glass companies produce short, medium, and long taper joints and will put whatever one you want on their products.

That's wht companies like Ace Glass have custom shops for.

In the era of globalization, EU glassmakers like Schott would doubtless like to enter the US market and vice versa. The US companies may have a tougher time in the EU market than Schott etc will have in the US market.

No businessman likes being poked and prodded by the ISO, nor should they? "
Beacuse that's the only post you made between S C Wack Calling ISO standards European and my pointing out that they were not.

[Edited on 8-2-2007 by unionised]

Sauron - 8-2-2007 at 11:48

Quote:
"Correct me if I am wrong but NIST is a government agency.
Dates from 1901, part of Commerce Department.

ASTM is a private organization.

ISO is an NGO, which means it is a pretentious private organization which would like to be santified by the UN It also is an offshoot of what is now the IEEE.

ANSI, is government or private? It's private despite calling itself a national institute, which is highly misleading, it is ninety years old and an offshoot of what is now the IEEE.

And yes very much in bed with ISO.

NOTE the only one of these with any official standing at all is NIST.

ISO is not part of the European Union government. It is a typical self promoting self serving NGO and its encroachments on national sovereignty should be regarded with due suspicion. ANSI is a creature of ISO.

I am especially dubious of ISO14000 which is their environmental standardization initiative . I bet it bodes no good for chemistry and chemists."

unionised - 8-2-2007 at 14:02

Oh, that sort of before.

posted on 6-2-2007 at 04:02 PM

"Besides which you seem to have missed a rather important point. America (specifically ANSI) is part of ISO, so those ISO standards that you seem to feel are being foisted upon you (which you have wrongly labeled as Euro standards) are every bit as American as they are, for example, English or French.

posted on 7-2-2007 at 12:56 PM

Correct me if I am wrong but NIST is a government agency.
Dates from 1901, part of Commerce Department.......

S.C. Wack - 8-2-2007 at 14:42

Quote:

Originally posted by unionised
For what it's worth, if you want to find European standards they are called "EN" rather than ISO.

Copy/paste from Schott-Duran:

"In addition to the international standard ISO 3585,
which lays down the type of borosilicate glass 3.3,
DURAN® laboratory glassware also conforms to
the many standards for glass laboratory items; for
example DIN 12 331/ISO 3819 for beakers and
DIN 12 347/ISO 1773 for flat bottom flasks.
The particular DIN/ISO standard is indicated on the
product pages of this catalog. When changes are
made to the DIN, e. g. as a result of adapting to ISO
recommendations, our dimensions are modified
appropriately in a reasonable time."

Had the thread been on Chinese glassware, I would have referred to Chinese standards as Chinese standards. Had we been talking of African glassware, I would have referred to their standards as African standards. Does this not make sense?

Copy/paste from Corning/Pyrex:

"Standard Taper:
...is the symbol used to designate interchangeable glass joints, stoppers and stopcocks complying with the requirements of ASTM E-676, and requirements of ASTM E-675. All mating parts are finished to a 1:10 taper.

Spherical Joint
...is the designation for spherical (semi-ball) joints complying with ASTM E-677.

---

Standard Taper
Symbol used to designate interchangeable joints, stoppers and stopcocks that comply with the requirements of Commercial Standard CS-21 published by N.I.S.T.

Spherical Joint
Symbol designates spherical joints that comply with CS-21."

As the ASTM link that I posted points out, the ASTM and NIST specs for joints are closely related. I don't know why you're going on and on about ANSI, it has nothing to do with this thread and you're the only one talking about them.

[Edited on 8-2-2007 by S.C. Wack]

unionised - 9-2-2007 at 03:10

"Had the thread been on Chinese glassware, I would have referred to Chinese standards as Chinese standards. Had we been talking of African glassware, I would have referred to their standards as African standards. Does this not make sense?"

Yes it does.

And if you wanted to talk anout European standards you should have refered to European standards; the EN series (as far as I know there isn't one for glassware but I haven't looked).

However, what you actually talked about was the ISO standard which (as has been discussed at some length) is not a European standard- it's the one drawn up by ISO who are an independent group, not part of of the European government and including representation from most of the world. But you refered to them as European standards which they never were and probably never will be.

The list of members of ISO includes ANSI and thus proves that Americans take part in ISO too. That means it isn't a European standard. Since you said (in this thread) that it was, it is reasonable to point out that you are mistaken and to offer evidence of this. That's why it has relevence to this thread. Of course, since there's no such thing as an EU ISO standard fitting the whole thread is wrong headed.

The glassware is not made by a standards committee, it's made by companies like Schott. They comply with their own local standard (DIN because they are a German company) and also with the ISO standard because (rightly or wrongly) it is recognised throughout the world and they want to sell internationally.
If they wanted to sell to the roughly 5% of the worlds population who are in the USA they might have chosen to adopt a US standard. The other 95% of us don't see any particular reason to follow the USA's standards. If the USA decided to join in with the vast majority (there are about 300 million Americans and about 6 billion people) the problem would go away.

The glassware still fits together.

S.C. Wack - 9-2-2007 at 03:43

Yeah, I was so wrong to tag a link to the actual standards used by Euro lab glass manufacturers with "Euro standards". What a huge blunder.

[Edited on 9-2-2007 by S.C. Wack]

unionised - 9-2-2007 at 09:12

Well, I guess it wasn't such a big mistake the first time, but I'm puzzled about your doing it again. Of course going on about the Euopeans forcing you to adopt EU standards was also wrong.
And then putting this in didn't help understanding.
"I always find it funny how Euros (vulture comes to mind) blame amerika for all the world's problems and see it as some sort of dictator, when problems are a human condition and much dictatorshit happens in Brussels and elsewhere in the EU."

It seems to me to be a bit like the thread somewhere on this site about "Texas law".
DIN standards are German and Germany is part of Europe so DIN standards must be European standards.
Texas is part of America so Texas law must be American law.
Except it isn't really.

BTW, My guess is the Schott-Duran would prefer to be thought of as a world company rather than European, but I haven't checked.

Sauron - 9-2-2007 at 11:52

DIN is certainly the German standard.

ISO again is not a Euro entity, it is a global NGO with roots to the pre WWII IEN now known as IEEE which started off rather a creature of Edison Electric.

It is worth noting that according to their own website ISO does not develop standards, rather if you condense all their highfalluting language, they are a middleman.

So, if something is a ISO/DIN standard it was developed as a German standard, then adopted as an ISO standard later.

Which may or may not be same as the EN official European standard. Probably is but if so that probably has more to do with standardizing on the DIN than with ISO butting in.

NGOs over time lose focus and just become self serving cottage industries. And ISO is an old NGO.

I am not a huge fan of IEEE mostly because of their role in the revisionist history of electrical technology being written at Case Western, which glorifies Edison (while taking a lot of money from Edison Institute) at the expense of the geniuses who actually did the creative work, particularly Nicola Tesla.

Edison was a hack of a scientist. His main invention was the industrial research lab. But he was a plodder and an exploiter.

S.C. Wack - 9-2-2007 at 12:38

Quote:

Originally posted by unionised
Of course going on about the Euopeans forcing you to adopt EU standards was also wrong.

DIN standards are German and Germany is part of Europe so DIN standards must be European standards.

1. What the fuck are you talking about? Now you're just making things up. My original post can only be read in the context of the post that I was replying to, immediately above it.

2. The Schott quote says that the DIN adopts ISO standards. They are one and the same. Reread the last sentence of the Schott quote until you get it. Yes, it's true: Schott-Duran is the largest European laboratory glassware manufacturer, ergo the ISO standard is indeed a standard for tapered joints, and there is nothing wrong with the very first post in this thread.

From where I'm sitting, you've got some sort of problem. Get back to us when you find a major Euro manufacturer of lab glass that does not follow ISO standards.

[Edited on 9-2-2007 by S.C. Wack]

unionised - 9-2-2007 at 17:07

1 I'm talking about this; for the first part....
"Why is it that we have to conform to Euro standards, "
An assertion made without any evidence and I didn't make it up; you wrote it.
For the record, here is the post above which gives it context.
"
Its not so much as they are different standards, just that as allways america likes to do things backwards. No offense but you guys have a way of complying to international standards but applying your own twist so its not entirely compatible and requires everything to be made differently.

Do you know how many textbooks i have labled, "international addition: not for sale in the US" ??? different vcr formats, etc.... prefered units of measure all that crap. All my chem lectures are prefaced with, "Any americans in here today?" "
My best guess it that relates to the same point I made earlier, specifically this one.
"The other 95% of us don't see any particular reason to follow the USA's standards. If the USA decided to join in with the vast majority (there are about 300 million Americans and about 6 billion people) the problem would go away."
For the second part. Hey! shucks- you pointed out the importance of context. Please let others judge the effect of context rather than running randomly chosen quotes together like this.
"Originally posted by unionised
Of course going on about the Euopeans forcing you to adopt EU standards was also wrong.

DIN standards are German and Germany is part of Europe so DIN standards must be European standards.
"
Let's do something dull an put it back in its context; tricky because those two clauses were in totally different contexts.
This is what I wrote.
"It seems to me to be a bit like the thread somewhere on this site about "Texas law".
DIN standards are German and Germany is part of Europe so DIN standards must be European standards.
Texas is part of America so Texas law must be American law.
Except it isn't really."
I was pointing out that being subject to the standards of one EU country does not mean being subject to EU standards. I even gave an example to help people out.

2
"The Schott quote says that the DIN adopts ISO standards. They are one and the same"
Er, no. Here's that last sentence.
"When changes are made to the DIN, e. g. as a result of adapting to ISO recommendations, our dimensions are modified appropriately in a reasonable time."

And, tacitly for other reasons. DIN standards my change without a change in ISO. Do you understand what e.g. means? What they actually say is they will stick to their own DIN standard; if that changes then they will change. That seems like reasonable local politics to me.

I clearly have a problem; it is that not all of what you say agrees with the evidence. Get back to me when you have addressed this. This is a scientific forum; if you cannot provide evidence for an assertion like
"Euros (vulture comes to mind) blame amerika for all the world's problems and see it as some sort of dictator"
you ought not to make it.
As for ". Get back to us when you find a major Euro manufacturer of lab glass that does not follow ISO standards."
I can't see why it can matter that any European ( or any other nationality) manufacturer follows an international standard or not. It's not my problem and it doesn't make the standard any more European.

Standard Marijuana Taper

earpain - 15-4-2020 at 13:56

Hi everyone. I chose to bump this 2007 thread because it seemed to have the highest level of nit-pickery, which is actually super useful when making a large glassware order.
So besides S/T, often 24/40, and then the world standard, I feel it's time to address the 'stoner-standard'....or maybe more scientifically I will refer to it as the 'Cannabis Industry' ground glass standard.

So both of the pictures here depict the same female ground glass connector, and the same device(I really cannot figure out the purpose of the device, but it happens to serve as an amazing vacuum trap or gas bubbler). In both pictures it is the bottom piece.

However the ground glass hollow stopper is not of the cannabis kin. It came with a chinese complicated scientific steam distillation kit. The joints were all 24/40 except there was a glass 2L steam generator with two necks. A main, centrally position neck which was 24/40, and a second smaller neck which merely served as a means to add more water into the steam generating flask without interrupting the distillation. The female piece was indeed labeled with TWO NUMBERS, and I do recall seeiing them often in the science world. That glass stopper (scientific) is flawlessly compatible with every female connector in this pile of odd devices that my trash exploring friend gifted to me.

There does not appear to be a central standards committee for cannabis smoking/vaping/atomizing ground glass taper.
Though most claim it will always be one of three, and the largest is '18mm'. Which is what my ruler is measuring the ID of the largest end of the female connectors to be.

If I wanted to order compatible joints with this cannabis standard, would 19/22 be the likely culprit? It seems that that cannabis standard implicitly follows the same taper ratio, which to be honest, does make ground glass confusion a little easier.

dawt - 15-4-2020 at 14:28

Sounds so. Maybe check the manufacturer's website (if you can figure out who that is)? I looked at a few and most seem to be using 14/23, 19/26 and 29/32 in Europe, though many don't specify the length of the joint. Might be different where you live.

S.C. Wack - 15-4-2020 at 14:56

Quote: Originally posted by earpain

There does not appear to be a central standards committee for cannabis smoking/vaping/atomizing ground glass taper.
Though most claim it will always be one of three, and the largest is '18mm'. Which is what my ruler is measuring the ID of the largest end of the female connectors to be.

If I wanted to order compatible joints with this cannabis standard, would 19/22 be the likely culprit?

Are you asking if the joints on bongs sold online in 19 mm size are 22 mm long, or have rogue bong enthusiast glassblowers invented a whole new thing like 19/18 or 19/24 instead of using standard parts? Bongware and labware are interchangeable.

earpain - 15-4-2020 at 15:26

Quote: Originally posted by S.C. Wack

Quote: Originally posted by earpain

Well yes just backwards. I discovered by shear chance that the two were interchangeable. And was asking if anyone had similar experience or more detail about it.

I'm in the US and there are stores everywhere with tons of glass devices. The experts all claim no awareness of a second number(the length of the joint) And this thread helped me better understand why that doesn't matter anyway. And even the 18mm vs 19 mm discrepancy still allows for a vacuum tight seal .

SWIM - 15-4-2020 at 18:01

A 19/22 probably has only 12 mm of contact length with an 18 mm.

19/26, 18.8/26, and 19/38 joints should all have longer contact areas with the 18 mm joint.

Like 16, 18, and 28 mm.

18.8/26? yes, there is such a thing. I can't explain why it exists, but it does.
I think precision glass made it. Whoever did I got some so I can attest to their existence.

Anyway, these longer contact patches might be nice for high vacuum applications.

earpain - 15-4-2020 at 20:53

Quote: Originally posted by SWIM

A 19/22 probably has only 12 mm of contact length with an 18 mm.

19/26, 18.8/26, and 19/38 joints should all have longer contact areas with the 18 mm joint.

Like 16, 18, and 28 mm.

18.8/26? yes, there is such a thing. I can't explain why it exists, but it does.
I think precision glass made it. Whoever did I got some so I can attest to their existence.

Anyway, these longer contact patches might be nice for high vacuum applications.

hmm, well you have got my gears turning now.
So both of the pics i attached, were intended to be high resolution close ups of this joining, and to be reasonable, that water addition neck had to have been a 19/22. So both of those pics are a male 19/22, forming a vacuum tight seal inside of a 18mm by X(where x is extrapolated by the same proportion ratio, though indeed, it doesnt really matter if its a bit longer or shorter)

So if the male stopper were 18mm and the female neck were 19mm, this joining wouldn't be possible. For the male side, anything that has a 19mm diameter section of glass, must thus also have an 18mm, and a 17mm, etc.

But for the female this statement would have to be inverted to apply to the absence of glass, not the presence of it.

Takes me back to math class. Linear functions, or just lines, always have a value m, aka the slope, aka the derivative. If all sloped are the same, the only variation that remains is the Y intercept, yes?

I guess I could imagine up a few lines of code that should be able to predict all possible ground glass joint connections.

Plus the diamond mill devices were probably already sitting and ready to grind after making batches of 19/22 necks all day, and the bong guild just used the cutter that was still out on the bench. They could have called it 17mm, 16, wouldnt matter.

Last thing:
In response to the 2007 pondering of how the short versions became a thing?
Sure, going in deeper may make a better vacuum seal. But it would also:
a. Signiicantly increase the chances of a joint seizing during thermal changes when using the glassware, not to mention chemical ones
b. once a joint does seize, a longer/deeper mating would only make it that much harder to unseize the joint.

This is all conjecture of course.

edit: the first picture is scientific male <-> marijuana female. The second pic, with the mysterious orange glycerine condenser, is simply marijuana male <-> marijuana female. They both slip, and lock, and turn, and slide with precisely the same evenness. And I think you're saying there is an 18.8 because it's a taper. Every size circle possible, within the range, is occurring . Maybe there's some quantum physics limitation to that, that's beyond me.

Probably more true for glass than most other materials.

A=πr(r+sqrt[h²+r²]) where r is the radius of a cone and h is it's height, A is the surface area

[Edited on 16-4-2020 by earpain]

Dr.Bob - 16-4-2020 at 07:45

Who cares what standards we use, the glassware I have seen is ALL interchangable. As stated, the longer joints fit into the shorter tapers on every piece I have ever seen, and the shorter ones fit into the longer joints just fine, in all but 1% if the cases (a few pieces taper at the joint, but that is a bad design). I have a few odd adapters that are 24/29 and other Euro sizes, but most are either all long or all short. If you find a long joint adapter, you can always have it cut to a short one with a diamond saw, I have had glass cut before, and it is not that difficult to do. But you cannot fire polish the ends once cut unless you regrind the joint. if anyone wants mixed adapters, let em knwo and I will look out for them. I have some 14/22 to 24/40 adpaters for sure, and some 19/38 to various sizes as well. No big deal either way, again they all are the same taper.

earpain - 16-4-2020 at 09:47

Quote: Originally posted by Dr.Bob

Who cares what standards we use, the glassware I have seen is ALL interchangable. As stated, the longer joints fit into the shorter tapers on every piece I have ever seen, and the shorter ones fit into the longer joints just fine, in all but 1% if the cases (a few pieces taper at the joint, but that is a bad design). I have a few odd adapters that are 24/29 and other Euro sizes, but most are either all long or all short. If you find a long joint adapter, you can always have it cut to a short one with a diamond saw, I have had glass cut before, and it is not that difficult to do. But you cannot fire polish the ends once cut unless you regrind the joint. if anyone wants mixed adapters, let em knwo and I will look out for them. I have some 14/22 to 24/40 adapters for sure, and some 19/38 to various sizes as well. No big deal either way, again they all are the same taper.

Dr. Bob thank you. I do love my diamond grinding wheels, and enough flame work skill/equipment to make occasional adjustments. I sure woulld love to obtain whatever is used to final diamond shaping of the various ground joints. Even the B2B glass suppliers sell premade ground glass tube ends, but not that piece.

Anyhow, when you say "it doesn't matter, they're all the same taper" does this apply to 14/20 <-> 19/22 as well? Forgive such ignorance, i'm about to make an order, perhaps I should send a U2U after this.

By the way, I also have always been very reluctant to do anything with flame after cutting anything ground glass joint related. But the sharp edges can simply be 'diamond polished'. or an entire 24/40 joint, from personal experience, can be heated over an air carbureted propane torch and the piece will work fine for joining. Propane simply won't provide enough heat to warp the glass

Dr.Bob - 16-4-2020 at 16:23

No, a 14/20 won't fit within a 19/38 joint, even at the bottom, and a 19/38 is too big to fit into a 14/20 joint, even at the top. I think they made it that way on purpose, even though the taper is the same, so you can't try to use the wrong sizes together. But you can mix short, normal or long joints of the same first number. (Is that the diastolic or systolic joint number?)

BTW, if anyone wants any premade joints, I have lots of them, in 14/20 and 24/40, plus lots of stopcocks and other glassblowing parts and pieces. I know a few people here have done some glassblowing.

Refinery - 11-7-2020 at 11:58

The fact that I started my glassware collection with 29/32(29/42) joints is making me mad seeing basically all glassware on ebay for half the price at 24/29(24/40) joints. I finally decided to cut the act and get half a dozen of reducers and expansers to be able to interchange the glassware. My bad I already have mostly everything acquired.

Dr.Bob - 11-7-2020 at 15:37

I have tons of 29/42 glassware, and sell it at the same price as the 24/40, sometimes even a discount. There are only a few items that I don't have, but I have scads of it. So don't feel bad, it is great for larger distillations and reactions. Good luck.

I also might have a few adapters as well, but running out of some sizes.

Sulaiman - 12-7-2020 at 10:53

Quote: Originally posted by Refinery

The fact that I started my glassware collection with 29/32(29/42) joints is making me mad seeing basically all glassware on ebay for half the price at 24/29(24/40) joints. I finally decided to cut the act and get half a dozen of reducers and expansers to be able to interchange the glassware. My bad I already have mostly everything acquired.

If you have a working still in 29/32 for solvents, water etc. that is useful for higher volumes,
I have not looked carefully but 19/26 might be a good choice (given that you have the29/32 still)
Most experiments do not need to be done at 24/29 or 29/32 scale,
Operating at 19/26 scale would save on space, chemicals, waste etc.

(I use mostly 24/29, I have quite a bit of 10/19 glassware that rarely gets used)

Eddie Current - 12-7-2020 at 13:01

What are peoples opinions on the maximum volumes that should accompany particular glass sizes?

Example: 14/20 & 14/23 = 500ml, 19/22 = 1000ml, etc.

RedDwarf - 12-7-2020 at 14:06

Quote: Originally posted by Dr.Bob

BTW, if anyone wants any premade joints, I have lots of them, in 14/20 and 24/40, plus lots of stopcocks and other glassblowing parts and pieces. I know a few people here have done some glassblowing.

I know you don't generally ship to the UK, but out of interest what would you charge (ignoring shipping) for premade joints, stopcocks etc?

Dr.Bob - 12-7-2020 at 16:48

Quote: Originally posted by Eddie Current

What are peoples opinions on the maximum volumes that should accompany particular glass sizes?

Example: 14/20 & 14/23 = 500ml, 19/22 = 1000ml, etc.

The largest flask in 14/20 I have ever seen is 500 ml, although I think they sell 1000 ml ones, but 250 ml is the most practical large scale I would do in a 14/20. And for distillations, the neck restricks the flow a huge amount.

For 24/40, I have gone up to 5L, and down to 50 ml, but I find that 100 to 2000 ml is the most reasonable range for 24/40.

The 29/42 flasks go up to 12 L, and down to 100 ml, but I mostly use them for 1L and up, but they are not that much larger than 24/40, so not a big difference. Easier to fit large stirbars through the joint, for sure. You can distill at a fast rate from this size.

Dr.Bob - 12-7-2020 at 16:52

Quote: Originally posted by RedDwarf

Quote: Originally posted by Dr.Bob

BTW, if anyone wants any premade joints, I have lots of them, in 14/20 and 24/40, plus lots of stopcocks and other glassblowing parts and pieces. I know a few people here have done some glassblowing.

I know you don't generally ship to the UK, but out of interest what would you charge (ignoring shipping) for premade joints, stopcocks etc?

Not sure which exact parts you want, but I ask the same price as for 24/40 parts, see the thread on glassware looking for a home for some photos and a spreadsheet of prices. The shipping to the UK would start at about $25 for a pound, and go up to about $50 for up to 4 pounds. Covid has created huge delays on international shipping, as well. It might be that DHl would be better, I have used that a few times now, and they are cheaper than USPS in some cases.