Sciencemadness Discussion Board

Glass Joint Grease and Pentane

electrokinetic - 7-4-2021 at 20:52

I'm doing an extraction with pentane, which I understand can be used to remove joint grease when cleaning glass. So if I use grease in assembling the glassware, can I assume that the chances are good of contaminating my extract?

If that's the case, is my only option using sleeves? What if I don't use anything? Achieving vacuum is not necessary.

dawt - 7-4-2021 at 21:30

Glycerine works well in those cases, as does a paste made from glycerine and starch. You can also get away with not using a sealant, but on the off-chance your glassware does get stuck you'll curse yourself for not investing those 10 seconds. :)

itsallgoodjames - 8-4-2021 at 05:41

Quote: Originally posted by dawt  
but on the off-chance your glassware does get stuck you'll curse yourself for not investing those 10 seconds. :)

This is why you keep around a piece of wood dedicated to lightly tapping stuck ground glass joints to dislodge them

electrokinetic - 8-4-2021 at 09:54

I'll try the glycerin and starch route. I have the wood, but would rather not have to use it.

Thanks both!

Panache - 10-4-2021 at 05:32

depends on how good your joints are. this cuts both ways as in if they are married well you can lose little without using grease but they are more likely to seize. If they are crappy you are compromised with or without grease...
Red wax is an old school high vacuum thread sealant that works well on gg joints. if i recall its one part iron oxide one part beeswax one part paraffin something...pentane wont take off every joint grease. the fluorinated high mw corning stuff is essentially insoluble in everything except itself.
i cant stand the sleeves, dont know why, they just seem so unnecessary, rather like this reply really, god what an inane 6 lines....lmao.

monolithic - 10-4-2021 at 05:51

PTFE plumber's tape is much, much cheaper than purpose made sleeves.

Junk_Enginerd - 10-4-2021 at 07:59

I use Krytox. PTFE grease. Though I only use it for things I don't mind having PTFE grease on them until the end of time lol, that does not come off with any solvent.