Sciencemadness Discussion Board

Frozen Glass Stopper

ScienceHideout - 18-10-2011 at 17:02

On the way from gym class to my locker, I said hi to my best friend- the chem teacher. She said that I have a project to do after school- As it turns out, last time we were in the lab (her and I enjoy doing experiments by ourselves after school) we left a stopper in the volumetric flask. Yep... you know what happened. To make matters worse- she imagined that putting it in the freezer would get it undone. Now it is my job to get it out. To make matters even worse- there is a molar sodium hydroxide solution in it. Any tips for getting it out? The flask in not mine, so I want to be extra careful.

Neil - 18-10-2011 at 17:08

dun dun dunnnn UTFSE

http://www.sciencemadness.org/talk/viewthread.php?tid=14343#...

BromicAcid - 18-10-2011 at 17:12

Since it has NaOH in it, it's a bit of a different scenario than some of the propositions in that thread. I wouldn't use heat on it. Maybe try to submerge the flask in water for a day or so and see if that loosens it up?

Neil - 18-10-2011 at 18:15

True.

http://www.lbl.gov/ehs/Lessons/groundGlassJoint.pdf

http://www.ilpi.com/inorganic/glassware/glassblowing.html


The soaking in coke trick in the last link sounds interesting.

Mixell - 18-10-2011 at 18:20

Putting it under running hot water and then trying to rotate the stopper does the trick (for me at-least). Molar sodium hydroxide doesn't seem to be too dangerous (unless you soak your hands in it for a long period).

hkparker - 18-10-2011 at 19:36

Try dripping toluene around the joint.

fledarmus - 19-10-2011 at 03:42

Things that have been successful in my lab:

1. Rocking the stopper back and forth with your thumb while the rest of your hand supports the joint rather than rotating the stopper can help.

2. Since the flask contains a sodium hydroxide solution, immersing the entire flask in warm (not hot) water for an hour or so might also help, occasionally rocking the stopper gently under water. Tapping the outside of the joint lightly and rapidly with a rubber hammer or stopper, or pressing a hard vibrator against it while it is under water may also help free it. If you have a sonicator you can soak it in, that is even better. You want at least the stopper and the neck of the flask completely submerged.

3. Suspending the flask by the stopper less than half an inch above a soft surface (hot pad or rubber pad) and gently tapping down on the edge of the opening around the stopper with a rubber or wooden hammer or pressing a hard vibrator against the outside of the joint might work.

Warning - wear gloves while trying any of these, and try to find a pair that will actually protect you from broken glass. The latex gloves won't even protect you from an aqueous solution if you've ripped them and your skin open with a jagged piece of glass, but even cloth gloves will protect you from the sodium hydroxide long enough for you to strip them off and wash your hands if you break the flask. Also wear safety glasses. 1M sodium hydroxide is not particularly hazardous but you don't want it in contact with your skin for too long - make sure you know where the sink and safety shower are before you start. If you have a lab coat or apron, that can keep you from having to strip off your shirt quickly if you happen to drop the flask against the desktop and it shatters and splashes on you. This is not a typical lab operation and the chances are reasonable that something will break before you get the stopper out. It doesn't hurt to be prepared.

unionised - 19-10-2011 at 11:53

I don't think that fledarmus has adequately emphasised the importance of wearing safety glasses.
Broken glass will cut your skin. Sodium hydroxide will, slowly, attack it and it will sting like hell if you get it in a cut. With just 1M NaOH the effects will be temporary: you would be very unlucky to get a scar.

But alkalies damage eyes very quickly and quite often permanently.

SmashGlass - 19-10-2011 at 12:06

One of those flasks doesn't cost so much.
Find a sabre on ebay and viola! Champagne style opening. :cool:

Now for my serious answer.
A heat gun, eye protection, lab coat, and some good heat gloves, if used properly would get it
unstoppered without doing any damage to you or the flask. Take a bit of water on the joint first and see where it runs in to.
Heat the joint, not the rest of the container, rotating it evenly around the joint when it gets warm you will see the water that has crept in disappearing.
Stop, and try to see if it will get loose using the heat gloves and a bit of "elbow grease" (your muscles).
If it is still stuck try a few more times repeating with the water to see if you are progressing.

If it's 1M NaOH it's not so bad, but do it in a plastic basin just in case.
You can always have some citric acid ready just in case of a serious f@$k-up.
As in, you bust the joint and get some on you, and are a bit paranoid. I would just wash it off and maybe a
dilute solution of acetic acid (vinegar) to neutralize the soapy feeling.

If you don't care about the NaOH solution (it costs like ? Nothing to make a new one) you could get some lactic acid into the joint.
That stuff lubricates ground glass joints like a hot knife through butter.
Its great! After a day if it still stuck chuck that into a sonicator for say 30mins...
Don't worry... It wont over flow the sonicator if the joint comes out.

Have fun.
I love stuck glassware.
- My own personal record for a stuck joint was 2 years (without breaking it)
on some very fancy and expensive glassware. Now that is what you call persistent! -

fledarmus - 19-10-2011 at 15:44

Wow, with a name like SmashGlass, you're a lot more patient than I am! When I've got a glass joint that won't work, it's either broken or working by the end of the day.

I would be very, very hesitant about using a heat gun on a sealed bottle, especially if it's a real heat gun and not one of those blow dryer wannabes. It's amazing how hot the glass can get, and how long it will stay that way. You might not actually blow up the flask heating it with a heat gun, but you could build up enough pressure that when the joint does come loose stuff will spray everywhere. You may also just make a very hot spot that will break as soon as you triumphantly remove the stopper and start to pour the solution back out.

Be patient and try the other stuff first. If you do decide to go the heat gun route, think about either working behind a blast shield or wearing a full face shield.

And don't even think about using a torch on a sealed system. Just toss it and replace it.

SmashGlass - 19-10-2011 at 16:23

Quote: Originally posted by fledarmus  
Wow, with a name like SmashGlass, you're a lot more patient than I am!

Thanks. Well it was custom made and very, very expensive. $$ :o "Big No no to it go brakey brakey!"
And I'm -SmashGlass- not -BrokeAnotherGlass-. He works beside me. ;)
Quote: Originally posted by fledarmus  

I would be very, very hesitant about using a heat gun on a sealed bottle, especially if it's a real heat gun and not one of those blow dryer wannabes.


I've done this heaps! Glass isn't very conductive heat-wise.
That is why we still use glass stirring rods and not carbon or graphite ones.
"Och! That's hot!"

Quote: Originally posted by fledarmus  

It's amazing how hot the glass can get, and how long it will stay that way. You might not actually blow up the flask heating it with a heat gun, but you could build up enough pressure that when the joint does come loose stuff will spray everywhere. You may also just make a very hot spot that will break as soon as you triumphantly remove the stopper and start to pour the solution back out.


Yes, I concede it could be a bit risky in untrained hands. Akin to shaving with a cut throat razor.
But not as much as you are making out fled.
If you look at my instructions carefully, one adds water to the joint. After applying heat evenly
using a "real man's" heat gun, not a sissy hair dryer, and when you see the water evaporating you stop.
The joint head isn't too hot, but hot enough to be uncomfortable to bare skin when
wrestling with the stopper. With the water in the joint it's both a method for dissolving salts
that form the joint lock and a visual aid. As always the devil is in the detail.
As for exploding hydroxide bottles of doom...?
I don't recommend sitting it on a hotplate to get the cork off. Next time use a plastic stopper too.

I am only offering suggestions which I have done and would do myself.
It is up to each individual to ascertain their own level of skill in such matters and act accordingly.

Cheers.

ScienceHideout - 20-10-2011 at 13:47

I went to school yesterday and attempted to fix it with a blow drier. My teacher reminded my to put on my face shield, gloves, and glasses and work in the hood (while she is shorter than me... and wearing no protection. The glass joint could've bounced off the baffle, thru the sash and in her eyes! Even though we didn't get it out, we will try again... btw she is the coolest. Just some stuff she said...

"We need an extension cord because father (I go to catholic school) was too cheap to spend an extra ten cents to wire the fume hood."

"Don't worry about the glass joint- if it breaks, it ain't my glass, it ain't your glass, it ain't a big deal."

Me: "Why doesn't the switch on this hood work?"
Her: Goes across room, flips a switch, and vrooooooooooooooommmmmmmmmm..........

Her: "Don't forget to get everything out of the fume hood before using it... I don't teach in this room so I don't know what this crap is..."
Me: "This looks like potassium chlorate and sugar dead reaction."
Her: "And This is probably iron and sulphur..."
Me: "Shouldn't we leave that in the hood?"
Her: " A bit of H2S ain't gunna kill us..." *Turns on purge fan* :)

I also told her that I will try again... maybe with the Coke Soak.

Endimion17 - 20-10-2011 at 14:40

Quote: Originally posted by ScienceHideout  
I went to school yesterday and attempted to fix it with a blow drier. My teacher reminded my to put on my face shield, gloves, and glasses and work in the hood (while she is shorter than me... and wearing no protection. The glass joint could've bounced off the baffle, thru the sash and in her eyes! Even though we didn't get it out, we will try again... btw she is the coolest. Just some stuff she said...

"We need an extension cord because father (I go to catholic school) was too cheap to spend an extra ten cents to wire the fume hood."

"Don't worry about the glass joint- if it breaks, it ain't my glass, it ain't your glass, it ain't a big deal."

Me: "Why doesn't the switch on this hood work?"
Her: Goes across room, flips a switch, and vrooooooooooooooommmmmmmmmm..........

Her: "Don't forget to get everything out of the fume hood before using it... I don't teach in this room so I don't know what this crap is..."
Me: "This looks like potassium chlorate and sugar dead reaction."
Her: "And This is probably iron and sulphur..."
Me: "Shouldn't we leave that in the hood?"
Her: " A bit of H2S ain't gunna kill us..." *Turns on purge fan* :)

I also told her that I will try again... maybe with the Coke Soak.


What a nerd. Seriously, fume hood?

Dude, get yourself a heat gun, eye protection, heavy duty gloves and an old thick towel to put on your lap. And then get down on it.
You'll just hurt yourself listening to her.

Magpie - 20-10-2011 at 15:15

When dealing with SO3 I was greasing 19/22 joints with silicone grease. One stopper was stuck hard, carbonized I think. I tried temperature delta, acetone, soaking in hot soapy water, and rapping on the table top - nothing worked. Then I read the glassblowing site linked above, and following their suggestion used the wood stick method. To my surprise and delight it worked well and the stopper popped right out!