[Fluorine]

1) I am looking for lab/joint grease but I can't readily find it online. Any recommendations? Can I use petroleum jelly/Vaseline in place of it? I heat up to <100 ºC, more often around 70~80ºC though. Would this risk dripping down into the product? I would like to continue beyond 1h of heating without worrying about the glassware bonding together.

2) I'm looking for a soxhlet thimble (24/40, 34/45 body) if anyone has one. I've seen cellulose ones online however I'm not sure if they are re-usable. I'd be interested in the price of a glass one. Feel free to reply or message me.

Regards,
Fluorine

[Maverick]

I wouldn't use Vaseline. I use danco plumbers silicone grease. But ive heard dielectric silicone contact grease works better

[Fluorine]

I appreciate the reply, I'll look into these two. Could elaborate why you wouldn't use Vaseline? Is it because it'd melt or is there other reasons?

[Maverick]

it would melt but there was some other reasons let me see if i can find the thread on another forum an link u

[Maverick]

Important stuff

Anyway my point is this... for a while, I have been using for my ground glass joints some "silicone dielectric compound" from Canadian tire at $7 a tube. That's the stuff used to shield electrical contacts in automobile connectors from moisture and oxidation.

I submitted both compounds to a series if tests, including concentrated HNO3, H2SO4, HCl, NaOH and a few solvents like Heptane and Isopropanol and it didn't react to any of them. I tested both greases on the ground glass surface of my dessicator under vacuum and it didn't try to creep off or suck in. Both compounds are remarkably similar. So far, the only difference is the outrageous price of the laboratory grease...

I'm always baffled by the price of labware and equipment from the official big-name lab suppliers... How do they get away with such outrageous prices? Maybe that's why meds from big pharmaceuticals are so stupidly expensive.

P.S. Sigmhumm-Aldrhumm sells the dessicator in the pic above for something like $600. I paid $25 for it, including a one-pound bottle of blue drierite!

So in conclusion, if you want to save a few bucks on vacuum grease, in Canada, go to Canadian Tire, or in the US to your local NAPA auto parts store and get the silicon dielectric compound!

http://www.progmontreal.com/arch/vacgrease.jpg

entire thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=15156

[Fluorine]

Excellent, thanks again!