Frozen Ground Glass Joint

[innerI]

Howdy y'all,

My glass reagent bottle and its glass stopper are stuck together. It's a ground glass joint. My basic soup and heptane are stuck in the bottle. I have tried running hot water over the joint and using all my strength to try to free it but it won't budge.

Does anyone have any tips on how to get the joint unstuck? Thanks

 

[blue.magic]

Here.

Okay seriously... most common aid is to apply heat to the outer joint and also cool down the insert if possible.

However be careful with the heat, especially open flame around that heptane. This is REALLY dangerous!

 

[leratiomyces]

Run joint under very hot water and try opening every 20 seconds or so

Or

Use heat gun or hair dyer on joint, try opening periodically

Or

Place bottle in fridge for a while

Or

Simpler try tapping joint with metal spatula, gently, while rotating joint.

Or

Pipette acetone at the top of the joint, it can work its way in sometimes and assist with release.

All the above have worked on various occasions.

Be patient......

 

[pitubo]

In general when working with ground glass joints (before they're stuck):

Ground glass joints are very sensitive to strong lye solutions. Whenever lye is about to get near ground glass joints, always grease them beforehand. The grease protects the fine surface structure of the ground glass from attack by the lye. It does not have to be fancy laboratory grade grease, regular petroleum jelly works fine. Apply only the thinnest amount and wipe off any excess with your fingers. As a confirmation that the joint is well-greased, it should turn almost transparent when the joints are fitted and pressed together. If any grease squeezes out, that is a sign that you used too much.

For the frozen joint that you are stuck with, I recommend the following:

- Apply ptfe lubricant (WD-40) to the joint. This has a very good ability to creep into the joint. If necessary, give it a few days to fully permeate the joint and apply more lubricant if needed. You can observe the progress by watching the joint turn clear where the spray moves in.

- Tap the joint from the side with a wooden spoon. Don't use metal, you'll chip or break the glass. Turn the joint while tapping it, to tap it at all angles. Tapping the outer part may help, but tapping the inner part is what you want most. Tap it from the side in such a way to make it move out of the other part. You obviously don't want to hammer it in any further.

- Heat with a heat gun or with a stream of hot water. Don't use a naked flame, especially so when the flask contains flammable liquids. You only want to apply the heat to the outer part of the joint, not to the inner part. The idea is that thermal expansion of the outer part will make it come apart from the unexpanded inner part. If you apply the heat to both parts, it doesn't work. Tapping as per the above point is also useful here.

Be careful when performing the above procedures. It is very easy to break the glass and spill the contents. Wear safety glasses and gloves. Wrap the flask in a plastic bag and then in another fabric bag. Keep it in or over a bucket to contain any spills

 

[innerI]

Thank you everyone for your help, I am happy to report I have freed the glass joint!

I used hot running water to heat the female part of the joint and I put a bag of ice on top of the male part, then I used a rubber mallet to tap the male part and it came free! It took me a while but I persevered and it finally came free. Wow I am so happy and relieved right now.

I have learned my lesson and in the future I will use ptfe tape/sleeves or some kind of grease on the joint. I had used the same bottle for several previous extractions but I didn't have problems until now. I guess the lye affected it slowly over time.

 

[leratiomyces]

You might want to use a sleeve rather than greasing the joint.
Using grease on your ground glass joints inevitably leads to grease in the organic phase and therefore, grease in the final product. It's difficult to remove and it seems a small amount always remains, no matter what you do.
Don't use it unless you don't mind smoking a very small amount of grease.