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Author: Subject: Ground glass joints - US to EU ISO adaptors?
picketfence
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[*] posted on 23-1-2007 at 05:31
Ground glass joints - US to EU ISO adaptors?


Has anyone here come across any adaptors to make compatible the US standard ground glass joints to the European and australian ISO standards? :o
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Sauron
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[*] posted on 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.
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Coldfinger
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[*] posted on 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
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Sauron
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[*] posted on 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.
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DrP
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[*] posted on 24-1-2007 at 02:18


That's a very good idea! Build up the slack with PTFE tape and all should be well.
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picketfence
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[*] posted on 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 ;)
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[*] posted on 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.
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Sauron
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[*] posted on 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.
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[*] posted on 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.
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[*] posted on 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?
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[*] posted on 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.
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[*] posted on 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?
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Sauron
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[*] posted on 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).
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[*] posted on 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?
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[*] posted on 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.
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[*] posted on 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?"
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S.C. Wack
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[*] posted on 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.
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Sauron
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[*] posted on 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?
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DrP
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[*] posted on 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.
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[*] posted on 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 :D

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]
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S.C. Wack
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[*] posted on 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]
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Sauron
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[*] posted on 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]
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Sauron
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[*] posted on 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"
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[*] posted on 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.
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Sauron
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[*] posted on 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.
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