Topic: Crizzling, was re: Dimpled Glass Decanter - what is it???

[aa]

Not sure from the image if this really is crizzling. For those who are interested in the science, this link gives some interesting information.
http://www.vam.ac.uk/res_cons/conservation/journal/consjournal29/crizzling29/index.html

[krsilber]

Great article, Adam.  I didn't know about the expansion and contraction with changes in moisture, that's interesting.

KerryKez, can you post a close-up photo of the stopper?  Does it look cloudy on the inside?  Maybe it's my imagination.

Adam, I've seen cloudiness on the interior of a lot of glass.  I've heard it called gaffer's breath or blower's breath.  What do you think it could be besides crizzling?  Here's a photo of the stuff I have in the bubble of my Pairpoint candlestick, magnified a bunch. 

[Frank]

Brilliant to see that a way of treating sickness has been found, time will tell if it does the job I suppose.

Clouding of cavities within glass is the result of water having gotten into the cavity after manufacture, the cloudiness being the impurities in the water that were dissolved in it separating from the water on the cavity surface. I presume the water molecules are escaping in warmer conditions. The water gets in through minute cracks that do not need to be visible to the naked eye. Usually it is found in bubbles that are reasonably close to the surface. So seeing the effect in that stopper is puzzling but it would be likely that there is some sort of fault that allows moisture to get in.

Cannot make much sense of you image Kristi, do you have a view showing more of the piece.

[krsilber]

Attached are a couple more photos of the candlestick (not good ones, but you get the idea).  It's 12"/25cm tall.  Pairpoint 'sticks seem particularly susceptible to it, whatever "it" is.  The cavity is large, extending through the whole body, and the glass around it about 4-5 mm thick.  If water is somehow penetrating it from the outside it might be possible that it's picking up materials from the glass on its way and depositing it on the inside, but I don't see how it could carry stuff with it through the glass.  If it is leaching material from the glass as it moves in, I would think it would be most likely at the inner surface, where there's a sharp gradient in the concentration of those materials.  Perhaps my candlestick is in an early stage of the crizzling process, when there's salt deposition on the glass but no macroscopic cracks, "incipient crizzling" as talked about on this page.  It does look like sort of like salt crystals when magnified.  At any rate, if there's moisture inside and the glass is susceptible to it, it could cause crizzling, no?

On this Corning page are more examples of crizzling.  I wonder if the picture of the foot is part of a candlestick.  Could be a vase, too.

[Frank]

I suppose it mustr be a form of the material break-down. There was a long discussion re oily glass, now in the archive forum that may shed some light on the issue too,

[krsilber]

Yeah, I read that thread a while ago.  That's weeping, a related issue.

[aa]

Adam, I've seen cloudiness on the interior of a lot of glass.  I've heard it called gaffer's breath or blower's breath.  What do you think it could be besides crizzling?  Here's a photo of the stuff I have in the bubble of my Pairpoint candlestick, magnified a bunch. 

I don't know enough about the science, so anything I say is conjecture. Bubbles such as your candlestick and the stopper shown above are micro environments where air is trapped at the point of sealing. Hollow stoppers and hollow stems are sometimes made using a "steam stick" rather than being blown "conventionally" down a blowing iron.

A brief summary of the process can be found here http://www.glassblowing.com/hotglass/facts.php

Sometimes using this process, there appears what I have always assumed is a carbon residue or similar on the inside of the bubble which appears immediately at the point of expansion. The glass can go cloudy and in some circumstances black. This discolouration completely disappears when reheating in the glory hole and the bubble becomes transparent. At that point the bubble would be sealed by one means or other.

Whether this has any bearing, I do not know.

Quite aside from this,  depending on temperature, it is possible for condensation to occur in sealed bubbles, and this moisture could cause problems if not adjusted by evaporation, which can be achieved by moving to a warmer environment.

Hope this helps.

[krsilber]

...this moisture could cause problems if not adjusted by evaporation, which can be achieved by moving to a warmer environment

Are you saying I have to leave Minnesota?  Hey, that's good enough reason for me!  California, here I come!

I thought about this when I first heard about steam sticks, but had since forgotten about them.  I also once read that sometimes glassblowers would take a mouthful of water before inflating a bubble, letting the steam do the work.  Never knew how much credence to give that, though.

Maybe I should put it in the fridge and see if moisture inside condenses.

Sorry, Kerry - this has gotten a bit off-topic, as Sue gently pointed out.  It would still be nice to see a photo of the stopper.  It may not tell us much, but if the glass is degrading it might at least suggest it's not brand new.

[aa]

...this moisture could cause problems if not adjusted by evaporation, which can be achieved by moving to a warmer environment

I also once read that sometimes glassblowers would take a mouthful of water before inflating a bubble, letting the steam do the work.  Never knew how much credence to give that, though.

I won't be trying that! Think about it. 

[Cathy B]

If it were ice water, you could make frit.