3 litre conical has cracked!

[Shane Phelan]

Ok I have heard back from the manufacturer. This was their response:

Any Erlenmeyer flask of any brand would be subject to thermal shock in the circumstances described by the customer and would very likely devlop cracks or even shatter. Direct flame should never be applied to containerware such as beakers and flasks. A diffuser of some form usally resting upon some form of support such as a tripod stand should be used.

But as a gesture of good will they (Fisher Scientific) have offered to send out 2 flasks free of charge! 

I should have them by Monday so give me a shout on how to organise getting a replacement out to you.

[Hop Bomb]

I didnt use a vacuum & the flask was dry going on the flame. Ive seen loads of videos online of people using theirs on their stove so I dont see why i should have used mine any differently.
Surely these are tested to way higher temperatures than the actual intended usage temp to ensure it doesnt fail & injure the user.

Cheers for the legwork then & now Shiny. Much appreciated   Il be in Dublin the weekend of 10th May so if you're around I could meet you somewhere convenient for yourself.

[Shane Phelan]

Yeah I have found the same when researching the proper usage of these items in terms of the amount of people using them on gas cookers. I suppose its just something to be careful about (for the other flask owners too) in the future as I don't think I will be able to get any further replacements.

[Hop Bomb]

No flame at all then or bunsen with diffuser?

[Shane Phelan]

Yeah that's what I'm taking from it. A naked flame seems to require some sort of diffuser whether that be the wire gauze type or one of these:

[RichC]

I've been using my flask on the gas jets of my burner since I got it over a year ago from brouwland. Don't know what you guys have but mine doesn't feel very thick walled. I thought these were bulletproof!!! Where can I get a diffuser? Need one for my paella pan anyway

[Shane Phelan]

I have seen plenty of people using them on naked flames without issue but all I can do is pass on the information that was given by the manufacturers. If it happens again I don't think I will be able to go back to them for further replacements.

Just search for 'heat diffuser' on ebay and they are very cheap.

[Will_D]

Its called a "wire gauze" Its just a small square of wire mesh (Copper or SS) that diffuses the heat.

As half of you here must have done some sort of science in secondary school, you never boiled a 50 ml Pyrex beaker on a Tripod support over a naked Bunsen burner as the small beakers just fell though the triangular hole!

Use a wire mesh - its standard lab pratice