Bubbles in Erlenmeyer flask

[blazin]

I just picked up two 5000 ml Erlenmeyer flasks from MoreBeer and while the are huge and friggin sweet, i have noticed a lot of small (and a few not so small) bubbles in the glass. Has anyone else used a flask with bubbles in the glass? I would think the air in the bubbles would expand and shatter the glass when i heat it. I'm thinking about asking for my money back on these. Sorry about the image quality, kinda hard to take a picture of a clear bubble in clear glass...

 

[eastoak]

i have one of those, i'll look when i get home.

 

[day_trippr]

Hahahahaha! I see a crap ton of bubbles!

Cheers!

 

[signpost]

I have a 2L flask that I picked up at the LHBS. It has bubbles in the glass like you described. I haven't had any problems with it. I've only used it a few times so far for making starters and dissolving/boiling priming sugar, but nothing bad happened when I heated it up on the stove.

 

[ajdelange]

The bubbles might not be filled with air. They might be 'filled' with vacuum. Or they might be filled with air. Lets assume they are. At room temperature of 293 K (20°C) whatever gas is in there is at some pressure. At boiling, 373 K (100 °C) the pressure inside the bubble is approximately 373/293 = 1.27 times the pressure at room temperature i.e. only 27% higher. I don't think that will be enough of a change to burst the glass.

This is probably a 'student grade' flask as you'd hardly need anything better for making starters. You can't expect perfection in such a low grade. I wouldn't worry about it. I'd try to get some better pictures (the only bubbles I can see in the posted photos are in the bubble wrap) that actually show the bubble so that should the flak break you can blame it on the bubbles and go back to the seller.

 

[eastoak]

no bubbles in mine but it sounds like ajdelange pretty much has the science of this whole deal wrapped up anyway. nothing to worry about.

 

[blazin]

Ajdelange- thank you for the detailed answer. I am going to take some photos with my Nikon (iphone camera wouldnt focus right) and send them to morebeer to document the imperfections before I try using it. I will let you know how it works out.