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Author: Subject: Bad days in the lab or with glassware?
oceandeep67
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[*] posted on 12-1-2022 at 03:27


Quote: Originally posted by itsallgoodjames  
Quote: Originally posted by Fyndium  
I've truly grown to hate magnetic stirrers.

It seems to be a technology that no one has gotten to work reliably. Their speed control is unreliable, the magnetic coupling is pretty much always too weak and causes decoupling every other time, and it is practical only for minuscule amounts of low viscosity liquids, as the electric motor itself is usually underpowered as well.

I have a stirrer that just simply died during overnight stirring.

My stirplate speed adjustment goes on runaway sometimes and it has caused similar troubles. The heating function isn't neither the best there is, but has been able to complete things so far with constant monitoring.

Overhead stirrer, first the improvised one from hand mixer, and then the actual one have been proven to be the best solution so far, and only limitation seems to be vacuum operation, although there are bearings for that too if necessary. The real overhead has power of 100W with brushless DC so it has a lot of torque, likely not to stall with anything that doesn't break the glassware itself and it's silent. The hand mixer, although being otherwise good, is very noisy and obviously overpowered. Having 500W of power, it is actually dangerous as it can even snap fingers if misused. I turned a coupling for it for ptfe paddle stirrers, and although rudimentary, it does it's job very well.

I suppose the brand plates are good, but their price tags start from $1k so it's somewhat prohibitive. Are there any proven good stirrers/stirplates with reasonable price range?


Get a used brand name hotplate from eBay for a few hundred dollars

Build your own.? Custom to fit your needs. If I can do it, I'm sure most of you can...
[Edited on 10-3-2021 by itsallgoodjames]
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oceandeep67
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[*] posted on 12-1-2022 at 03:31


My apologies^
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oceandeep67
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[*] posted on 12-1-2022 at 03:49


Keep in mind I was a child at the time. Like 12 yo. I was performing a combustion reaction in my attic (did not want mother knowing). Anyhow, make a long story short I burnt the house down.:(
So yeah, locals think I'm a fanatic about safety/insane but I/we know how dangerous science can be!
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BAV Chem
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[*] posted on 26-3-2022 at 01:56
A particularly bad week (or two)


So over the past two weeks I've somehow been very clumsy. :(
For one I made some nitrotetrazole over a week ago and it was all looking good until I managed to knock over the beaker, spilling all of the precious solution onto the bench. Most of it could be recovered by carefully pipetting it back up (ik this is terrible lab practice) but then the next day the same thing happened again. At least I managed to recover half of my product somehow...

Yesterday I reached into the cupboard to get out some acetone and knocked down two bottles of formamide and ethyl formate respectively which both shattered on the floor. After cleaning that mess up (nothing was recovered) I found that acetone didn't work for what I was trying to do and that ethyl formate would have been much better. :mad:




You forget what you know but alas you don't know what you forgot...
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