Sciencemadness Discussion Board

Broken flask from heating

BILLBUILDS - 21-2-2017 at 14:21

Yesterday I was doing a distillation with a 3LFlat bottom round flask and all of a sudden it cracked in two?? I was using my kitchen stove and was only about 10 mins in. Was I putting in too much heat for the flask? Or was it just dodgey?

Edit: excessive typos

[Edited on 2-22-2017 by zts16]

anewsoul - 21-2-2017 at 14:39

What was the heating element like? Was it directly touching the heating element?

BILLBUILDS - 21-2-2017 at 16:44

It was a glass heating elenent and I think o was

JJay - 21-2-2017 at 22:27

I wouldn't generally advise heating a flat bottom flask directly on a stove burner. Although a round bottom flask can usually tolerate higher temperatures, the maximum working temperature for borosilicate is usually stated as somewhere around the very lowest red heat.

LD5050 - 21-2-2017 at 23:02

No never put your flasks directly on the heating elements, hot plates and heating mantles are fine but kitchen stove heating elements will always break the flasks. I broke about 3 flasks this way when I first started messing around with chemistry lol.

violet sin - 21-2-2017 at 23:27

I would not advise playimg where you eat. Spills happen so don't practice any toxic chem where you don't want to relpace contaminated surfaces later. Boiling solutions or acidification of (bi)carbonates will cary droplets of solution around the room. Weighing things or even pouring from one container to another will spread particles. Use of silverware really bad idea... Begging for trouble.

You really don't want to learn this by hurting someone. Things like a hotplate, stainless thrift store utensels and some bowl's etc can be had for cheap... And spraypaint (5$/can)them a bright orange or pink on handles/undersides, power cords etc. to signify yours not for food.

Never know when a guest will reach for exactly the wrong item to use, but most will ask befor grabbing some gnarly looking stuff.

JJay - 21-2-2017 at 23:38

Quote: Originally posted by violet sin  
I would not advise playimg where you eat. Spills happen so don't practice any toxic chem where you don't want to relpace contaminated surfaces later. Boiling solutions or acidification of (bi)carbonates will cary droplets of solution around the room. Weighing things or even pouring from one container to another will spread particles. Use of silverware really bad idea... Begging for trouble.

You really don't want to learn this by hurting someone. Things like a hotplate, stainless thrift store utensels and some bowl's etc can be had for cheap... And spraypaint (5$/can)them a bright orange or pink on handles/undersides, power cords etc. to signify yours not for food.

Never know when a guest will reach for exactly the wrong item to use, but most will ask befor grabbing some gnarly looking stuff.



That too. I really have no idea what you had in your flask; for all I know, you were preparing some cinnamon essence for making red hot candies, but you don't want to be using reagent grade chemicals in your kitchen or with kitchen utensils.

violet sin - 21-2-2017 at 23:57

Funny, I once weighed up a bunch of cinnamon powder for an extract. Bought several pounds of the cheap stuff from a bargain store. I was being carefull to not use anything but food/spices in the kitchen. And carying weighed powder outside to alcohol. In the process I breathed enough powdered cinnamon to cause a really strange rash of super flush(red and hot) areas of skin to go all over me and they moved quickly, with super distinct borders. Itchy and worrysome but nothing came of it. That was with food in a food area and still not fun, some times ya just cant win

PHILOU Zrealone - 22-2-2017 at 15:06

Gas stove heats the iron ferronery very much and when the glass is put against it there is some stress occuring at those overheated spots...especially if the liquid inside the flask is not wel agitated and containing a lot of suspended solids...In this last case you may have charing of the suspended solid at those points that becomes dry while just next to it the liquid is agitated by vertical convection thus causing much cooler aeras...the glass even if Pyrex doesn't like that...and usually cracks.

[Edited on 22-2-2017 by PHILOU Zrealone]

Sulaiman - 22-2-2017 at 15:21

A heat diffuser may help http://www.ebay.co.uk/itm/SIMMER-RING-PAN-MAT-HEAT-DIFFUSER-...