Tricks for glass that’s eternally stuck to each other?

I have a mechanical cold trap. One of the glass inserts is just absolutely impossibly sealed to itself. I can only put so much pressure trying to twist it before the glass is going to break. I assume the vac grease just became solid over time. So, any trick to separate these two glass pieces before I try a jack hammer

boiling hot water bath… then try and chill the smaller side only…

You could try a heat gun to get the glass to expand a bit.

Heat the outside joint enough to expand it enough to break the interference fit. the trick is to try and keep the inside joint cooler so that only the outside joint expands.

I also swear by taking cheap thin vacuum grease, putting a bead around the top of the joint, heating it intill it starts to “melt” into the joint, im not sure if this does any real help, but i swear by it, i think it works


A heat gun slowly ramping up temp
All glass. Might get heated but around 250 C they let loose


Temperature differential. Heat the female joint and try to keep the male joint cool(er). Glass expands roughly .0005" for every 100°F and inch of diameter.


Use a wooden spoon, whack the joint and rotate, hit it harder than you think is ok, this is the tried and true method for stuck bong slides, downstream, and illidelph coil condensers


You’ll have to hit it with the torch. The trick is to make the outer part expand more than the inner so it actually requires very brief and fast heating

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I got one loose after boiling it. The other one has been stuck forever and seems cemented lol. I have a heat gun, but I’ll try a torch to really shoot the temp up fast

Fill the inside with ice water (or something colder) up to the joint. Heat the outside of the female joint with a heat gun, and twist hard!

I second the torch, use two of them, hit the outer glass for 5-10 seconds on opposite sides. With heavy gloves on, twist apart