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Author: Subject: Bad days in the lab or with glassware?
Lambda-Eyde
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[*] posted on 29-3-2013 at 14:31


I just salvaged 5 heating mantles from the trash outside of the biotechnology department. They were stored outside and we've had snow on and off for a few months, so they were wet. Since they after all are heating mantles, my immediate reaction was that plugging them in at low heat would dry them. The first one (one of the 500 mL ones IIRC) functioned properly. To test it, I touched it to see if it was heating up. Of course I got a shock... A nasty experience, but what the fuck could I expect from touching unisolated resistance wire hooked up to the mains? I then proceeded to plug in one of the 1L ones. Bam, there went the fuse... Luckily it was on one of the two lines in the house with automated fuses, so I could just switch them on again. But I hadn't learned, I had to test the largest one too. BAM! The regulator caught fire, and the fuse went out again...

Only then did it dawn on me: Wet heating mantles... Is it really a good idea to send an electrical current through a bundle of resistance wire soaked with water, in order to dry it?


Sometimes I'm impressed by my own stupidity...




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[*] posted on 29-3-2013 at 15:30


I was setting up a 500mL mantle recently and accidentaly plugged it directly into the wall socket instead of the variac. I didn't realize it until I touched the mantle a few seconds later - ouch! I was more worried that I might have burned out the mantle than anything else. But apparently it survived. I imagine that splicing a burned out heating mantle wire might be difficult.



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elementcollector1
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[*] posted on 29-3-2013 at 17:07


This was fairly recent, about a week ago. I was cooling a solution of sodium nitrate to extract as many crystals as possible. (Eventually, I just boiled it all the way down, got a bit more.) I placed a beaker full of the hot solution inside a beaker full of snow (oddly, it snowed last week! And there was a combination thunder/hailstorm that week as well.), and left it in the freezer to cool. Unfortunately, I left it overnight, forgetting about it.

I came back the next morning to find that the larger beaker (1000mL) had cracked. Unsurprising, really, but what was surprising was the crack itself: A perfect circle, all the way around the bottom of the beaker, leaving only the bottom surface (which made a rather nice watch glass). The snow, meanwhile, had turned to ice, and took quite a while to thaw, even inside. I suppose the smaller beaker prevented the snow from expanding when it froze, causing mechanical stress on top of thermal stress from being in the freezer so long? Anyway, it's interesting that the crack was so perfectly made.

The sodium nitrate survived just fine - decent yield, too. Next time I'll just put the hot/warm beaker in the freezer, and be done with it.




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[*] posted on 30-3-2013 at 03:49


Quote: Originally posted by elementcollector1  

Unsurprising, really, but what was surprising was the crack itself: A perfect circle, all the way around the bottom of the beaker, leaving only the bottom surface (which made a rather nice watch glass) ... Anyway, it's interesting that the crack was so perfectly made.


This has to do with how the beakers are made, the seam between the bottom and the rest of the beaker can crack open. I have encountered the exact same thing when heating water in an old 1000 ml beaker.

[Edited on 30-3-2013 by kavu]
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[*] posted on 30-3-2013 at 10:24


The first practical we did in school many years ago was to heat water to boiling using a Bunsen burner flame. An acquaintance of mine was sitting down on a stool, and lifted his hot beaker off the tripod onto the bench using tongs. Whilst he was holding it in mid-air, the bottom came off cleanly, spilling hot water all over his lap. A lesson to remember, I think.



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Pyro
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[*] posted on 30-3-2013 at 10:50


one tends to remember funny things! I rarely sit while doing chem, but when i do its on a stool so i can move away fast.
One time i was standing on my stool while getting of my lab workbench because i had installed a light bulb, it toppled over, and so did I, i landed flat on my back very lucky i wasn't hurt badly!




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mayko
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[*] posted on 10-4-2013 at 17:44


My 500 mL round bottom flask just pinged and cracked while I was steam distilling some orange peels :( Dunno why
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[*] posted on 13-4-2013 at 12:29


Quote: Originally posted by Pyro  
one tends to remember funny things! I rarely sit while doing chem, but when i do its on a stool so i can move away fast.
One time i was standing on my stool while getting of my lab workbench because i had installed a light bulb, it toppled over, and so did I, i landed flat on my back very lucky i wasn't hurt badly!


I was at work one night (I work at a Mexican restaurant), and the waitress had mopped the tiled floor without telling me...I slipped, landed heavily on my back, causing me to launch the glass jars I was carrying out of my hands. Amazingly, I was OK and all of the jars were intact! :o




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Pyro
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[*] posted on 13-4-2013 at 12:53


Lol, not lab related, but you were very lucky!
Talking about slipping, My dad waxed the floor recently, which is already very slippery varnish, now Me (and the cat) are always slipping. I went down on my ass, it really hurts! and the cat always comes tearing down the hallway and then slips and smashes into the wall!


[Edited on 13-4-2013 by Pyro]




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[*] posted on 13-4-2013 at 19:44


what brand of glass where you using and how old do you think it was?
Quote: Originally posted by mayko  
My 500 mL round bottom flask just pinged and cracked while I was steam distilling some orange peels :( Dunno why




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[*] posted on 13-4-2013 at 21:03


Quote: Originally posted by Funkerman23  
what brand of glass where you using and how old do you think it was?


New synthware; the postmortem was that the flask had gone dry and heated up before I added more water. User error; derp! Next time I might try externally generated steam. I had thought that direct distillation might be easier, but maybe not.
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[*] posted on 26-6-2013 at 10:01


Did not happen to me, but my co-worker shoved a stir rod through an evacuated dewar flask. Needless to say, it imploded. Fortunately, no one was injured, but man was it loud!



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[*] posted on 27-6-2013 at 17:00


Quote: Originally posted by sargent1015  
Did not happen to me, but my co-worker shoved a stir rod through an evacuated dewar flask. Needless to say, it imploded. Fortunately, no one was injured, but man was it loud!


And here is the aftermath :o

image.jpg - 127kB




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[*] posted on 30-6-2013 at 13:07


I have destroyed a shitload of boiling flasks, dropped twice an entire distilling setup(with 5000ml flasks and full length thermometers, the other had dropping funnel attached to it and everything went into fine shatters at the moment they met with the concrete floor). Another distilling setup had 3 liters of boiling sulfuric acid and other one had few liters of ether. Once I melted one steel reactor with (probably thermite reaction) too hot reaction. I also spilled a gallon of ethanol on tha table and the whole table turned into instant firestorm due to propane burner but CO2 distinguisher saved the lab pretty nicely.
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[*] posted on 30-6-2013 at 13:19


This is a bit embarrassing but when I received my very first Laboy order I had a coiled reflux condenser. Now I don't know how the first crack formed but low and behold there was one in the middle of the coil before the days end. I wish I knew if coiled condensers are supposed to have a tiny ring to then if you lightly tap the walls or if they are supposed to be that fragile but I was heartbroken. I had planned on using that for ether( now I have a 400mm Allihn and a 600mm West for that but I haven't tried either yet so who knows if those two will do the job). 60 bucks long gone but that still stings to this day. I've been scared to order anything coiled by Laboy since..opinions on that are always welcome though.

over tightened a stopcock from them as well but that was less irritating.




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[*] posted on 30-6-2013 at 13:40


I smashed the end off a 2 liter separating funnel a few days ago. It was a nice clean break at the end.

I might get a glass blower to seal it one day, then I'll be the coolest kid in town with a 2 liter pair shaped! (Unfortunately I don't know a glassblower!)

[Edited on 30-6-2013 by sonogashira]
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[*] posted on 30-6-2013 at 19:15


Quote: Originally posted by testimento  
I have destroyed a shitload of boiling flasks, dropped twice an entire distilling setup(with 5000ml flasks and full length thermometers, the other had dropping funnel attached to it and everything went into fine shatters at the moment they met with the concrete floor). Another distilling setup had 3 liters of boiling sulfuric acid and other one had few liters of ether. Once I melted one steel reactor with (probably thermite reaction) too hot reaction. I also spilled a gallon of ethanol on tha table and the whole table turned into instant firestorm due to propane burner but CO2 distinguisher saved the lab pretty nicely.

Impressing!
Seems you dont have a learning curve but a flatline. In the case of your early demise you should donate your brain to science - maybe they are able to figure something out... ;)

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[*] posted on 30-6-2013 at 19:25


Quote: Originally posted by sonogashira  
I smashed the end off a 2 liter separating funnel a few days ago. It was a nice clean break at the end.

I might get a glass blower to seal it one day, then I'll be the coolest kid in town with a 2 liter pair shaped! (Unfortunately I don't know a glassblower!)

[Edited on 30-6-2013 by sonogashira]


If you are near a university, most have a glassblower in the art department, or even in their Chem department. They are coveted since accidents happen a LOT in undergraduate labs. Good luck!




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vmelkon
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[*] posted on 3-7-2013 at 13:18
Broke a clamp


I broke a clamp :(
Has this happened to anybody before?
The clamp comes from united nuclear and looks like this one
unitednuclear.com/index.php?main_page=product_info&cPath=25_30&products_id=340

I was undoing the back screw to remove it from the stand. The thick metal part of the base broke. It metal surface of the broken face reminds me if carbon steel but I don't think it is carbon steel. It is perhaps a zinc alloy.

Damn. Now I'm down to one :(
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[*] posted on 3-7-2013 at 13:43


The only clamp I ever broke was just that same design. I simply overtightened it.

I'm not so keen on that design. I've come to prefer the three-fingered type. I like the kind with a screw for each side, but the single screw type is serviceable as well.

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[*] posted on 3-7-2013 at 14:12


60$ thermometer... Enough said :(


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[*] posted on 3-7-2013 at 15:52


Recover that mercury! My condolences on your thermometer, <strong>Mailinmypocket</strong>. What type was it?



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[*] posted on 3-7-2013 at 16:31


Quote: Originally posted by bfesser  
Recover that mercury! My condolences on your thermometer, <strong>Mailinmypocket</strong>. What type was it?


The mercury was my main priority ;) it was a -1- 201c in 0.2c increment thermometer... No idea what happened, I knocked it accidentally on the hotplate and it went *tink* and the bulb broke clean off.
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[*] posted on 3-7-2013 at 23:54


Well, fuck.

Think it's time to replace all the similar clamps from my lab before something catastrophic happens. Hanging 10- and 20-liter flasks full of highly corrosive, toxic and flammable +1g/cm3 liquids supported by those crap-clamps is not a good idea after all.
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[*] posted on 4-7-2013 at 05:14


I know those clamps. Crappy and worthless pieces of equipment capable of holding only the lightest stuff in situations where it will never encounter any corrosive fumes.
You don't make a clamp from zinc alloy profiled sheet. It's destined to fail shortly.
The best clamps I've ever encountered and managed to buy are either cast stainless steel or brass ones. They can last a lifetime if properly maintained.

When you buy clamps, forget about this pressed sheet crap. It's being sold for the same, if not higher, price as cast clamps - just because they're laboratory clamps. It's a rip off.




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