Glass Crizzling

[Wattana]

Hi David,

You have made some very interesting comments and observations.

I have about a dozen 20th century glass overlay bottles, and they fit your remarks very well...

The ones which have developed the worst crizzling / stress cracks are my camphor glass (bubble suffused) ones. Next come the clear glass overlays, which have fewer, but larger (deep) cracks. Last are the opaque glass bottles (solid colour, both white and yellow), which have NOT developed any cracks at all.

Tom

[David]

Hi Tom,

I am glad that you find the idea plausible, but sad to hear that you have so many that cracked. Do you have access to a long wave UV light? I wonder if these bottles will react to UV light in the dark.

If my idea is true, then eventually the solid color based overlay might also crack. It might be a good idea to remove the top carefully and treat it gently in the future.

Do you recall how long you had the camphor glass one before it starts to crack? How long before the clear glass crack?

Do you have any that is jar like or do they all have the flat oval form? I am curious if a jar form will also crack in a similar fashion, or if it will be different. As one of my 2nd favorite is a small jar like overlay, and I hope it will not crack for years to come. It is actually one of the reason I was so interested in this topic.

I am not sure how they make it flat... do they press it after blowing? Or do they blow/machine inject into a mold then overlay on side to hide the mold mark? Or do they carve the whole thing out of a solid block? It would be interesting to know how they did it in the past versus pre 1950s (I recall reading somewhere that is the time when electrical drill becomes cost effective to carvers) and now.

David

[Wattana]

Hi David,

No, I do not have a long wave UV light. What would you be looking for if using this light?

All the affected bottles were kept in special storage drawers in fairly stable conditions. Temperature variation in Bangkok is small - 24 to 33 deg C. But we do have humidity here.

The camphor glass bottles started showing signs of deterioration after the first 3 years or so, and got progressively worse. The photos posted on this thread show what they looked like after 10-12 years. The clear glass ones have about the same timing.

The opaque glass bottles were bought 15 years ago, and still show no signs of damage.

None of my glass bottles are jar shape. They are all flattened oval form. I am not sure how they are made today, but I imagine the bottles are roughly formed in a mould and blown into shape while still soft. As far as I know they are not made in two halves. Many of the better old bottles were carved out of a solid ingot or block of glass, so would have been created exactly like a stone bottle.

Tom

Tom   

[Fiveroosters aka clayandbrush]

Dear David,
it is good to have another technician here! I am not so convinced that the problem of crizzling belongs to the vibration stresses. First at all the problem exist on plain bottles too, not necessarily the carved ones. And the distribution of the crizzling that I have seen on some example is very uniform. I suppose that it must be related to the fabrication process of the glass, like too quick cooling or something like that, or something wrong in the recipe. Also about the influence of the bubbles I am not so convinced. It is true that we wave two different materials, glass and gas, but how can the infinitesimal force of a minuscule bubble of compressed gas influence the strength of the glass? Frankly, I would not be surprised if a bubbled glass has a stronger rigidity of a plain glass, because of the additional strength of bubbles surfaces. The same must be said about the influence of the cork, that it is absolutely null; remember that glass has an enormous strength. Think on the chain of electrical insulators that carry the unbelievable pulling  force of the electric power lines.
Kind regards
Giovanni

[David]

Hi Tom,

I am curious that if they applied any kind of resin, opticon, plastic over the modern bottle. A UV light is a very useful tool to check treated jade, and I notice that it is quite useful for bottles or bottle like items.

Out of curiosity, I UVed all my items that might be snuff bottles in a dark room at night. And I noticed area where they put glue on (jade or serpentine bottle I posted), tops that were rubber or glass stained to look like green jade, etc... I noticed that the some interior painted bottles will have some paint color that reacts. I am still fooling around with it, but I think it is a useful tool.

But, a word of caution... UV light damages painting (so not recommended to use on internal painted unless they are tourist bottle like mine). And you need to wear UV safe glasses or else the end result is similar like looking into the sun.

Hi Giovanni,

I enjoyed your analysis and if I recall correctly you said you are involved with
http://gotheborg.com/  ? If yes, then a double thanks to your information. I learned a lot from that site and found the Chinese 60 year cycle to AD year chart very useful.

At first I also was thinking along that path (regarding too quick heat/cool cycles), but then I think it will crack the bottle immediately.

I don't think it is pure vibrational stress, but is vibrational stress/temperature change on already chipped glass accumulated over a long period. Kind of like when you want to split a tile or cut a glass. If you don't score it, it is very strong and will not split. But once you score it, then a gentle knock will split it. So, all the little chipping when an electrical tool is used, is like making a bunch of little scores.

Then over the years, these scores gets bigger and bigger. Until it reaches a critical point... Like if you see arctic ice cracking on the TV. One it weakens to a certain threshold, the difference in weight/shape of ice on ocean can make the split.

I am not sure regarding bubble tension strength can strengthen glass. But, I do know that adding certain impurities will strengthen glass (like lead), but I think it has more to do with the binding and not structural.

I don't have a lot of bottles or actually see them in physical, so I can't say... are the camphor thickest, then bubble glass, then solids?

I think the bubbles weakened the glass, because there is less glass for the chip to grow into splits. If the wall thickness is 5mm, then a bubble glass might only have 3mm effective at a big bubble or even thiner if a few bubble lines up. While a solid glass will have the full 5mm.

Using the same line of thought... if you have a very thick tile that is scored, it take a pretty heavy blow to split it. Any lesser blow will have no effect. So, the threshold to damage is higher. Perhaps solids is like that and they might never split.

One thing to keep in mind is that rigidity do not equate to toughness. A good example is nephrite versus jadeite. Nephrite have a hardness of 5.9-6.5, while Jadeite is 6.4-7. But, nephrite is tougher to breakage because of the more random way it is formed, while jadeite will shatter more easily. I recall reading that is one of the reason why so many archaic nephrite artifacts survived.

David

[Steven]

Hi David,

I have a feeling that you will be a huge assets of the Forum anytime soon with your analysis skills.

I really enjoy to read your post, its very technical. However I do agree with Giovanni that the problem of crizzling might not belongs to the vibration stresses.

I was discussing the mold problem which happened in most of  my 70s-80s inside painting snuff bottles with him, and he told me that was the ingredient of glass was not right, the Lead played a big rule on the the problem, as we know the glass industry was underdeveloped during the period, those bottles were made in small studio and manufactures, they might do have enough experience and techniques to make the high quality glass with right  ingredient . I am not a technician and know nothing about the glass industry, that was told a experienced chinese dealer, it could be right or to be argued. But it sounds more reasonable to me.

Again, that might be the internal cause of the problem, the change of the temperatures could be a external cause.

That was only 2 cents.

Steven


 

[David]

Hi Tom,

I just realized I missed something... The drawers you are talking about is something special for storing snuff bottle? It controls temperature and humidity? Like a cigar humidor or wine cellar? Wow, that is interesting, you must be a very serious collector.

Hi  Steven,

Thank you for the nice words, I hope my thoughts are useful and can repay some of the things I learned from here. Hence, contributing my 2 cents.

  If we put enough 2 cents together, then it can be a million! I enjoy the discussion and it is a very interesting topic to me. Right now, I am more interested in bottles, but when time allows I will look around for more information on glass making.

A lot of things have no black/white answer,  Who knows, it might be a combination of everything we discussed plus a few more that we did not think of.

David

[Fiveroosters aka clayandbrush]

Dear David,
be realistic: think about the door glass of an oven. During his life it will run up to about 300 degrees Celsius and drop down to ambient temperature thousands of times. Have you never seen the crizzling problem on them? And do you think that a glass stored in a drawer where it can have a temperature variation of about 20 degrees Celsius in a time span of six months is developing crizzling because of thermal stress? It is not possible, really; the only explication is the nature of the material.
To give you an idea, in my latest job we did use steatite electric insulators. Steatite is fired at a lower temperature than glass. One of the tests that we performed on them was to heat the insulators up to 800 degrees Celsius and then dip them suddenly in cold water. The bad quality ones did crack, but most of them was developing a fine net of crackles that was not visible at naked eye. The good ones was not cracking at all.
About the cheek test, we had a discussion on this issue not long ago:
http://snuffbottle.smfforfree.com/index.php/topic,1749.0.html
If you read how and why it works, you will understand that it is a good test for detecting different materials when the difference is a substantial one. It will not surely help you to differentiate between two similar type of rocks.
Yes, I am on Gotheborg too. Are you too a member there or are you only accessing the public area?
Kind regards
Giovanni

[David]

Hi Giovanni,

I access the public areas, I went there when I was wondering why there are so many marked bottles, plates, bowl,... on etsy and online sites. The catalog and organized way that the marks are documented there is very nice for people like me. Then I tried to calculate the 10 sky numbers versus the 12 ground numbers... completely lost myself and searched around for a translated chart. And stumbled back on to that site.

It is quite funny, the reason that I went there the first time. I bought a tourist snuff bottle of a couple of cats on etsy (like 15 bucks or so), the lady was going to close her shop and put on a 50% sale. So, I went ahead and bought a 5 dollar set of demi cup/dish with the made in cheng hua mark, a old chinese hand puppet of a folklore judge (one of my favorite character), and a couple of trinkets. I know it is most likely a fake, but was wondering if it is a fake made during the Ching Dynasty for export. If it is, and even though it won't worth much, it will be a interesting thing to have and fool around with. I kind of figured out after checking that site and a few others that it is an Chinese Imari demi cup/plate worth like 10-20 bucks on ebay   

Thank you for the link to the other thread, it is interesting. Since chloromelanite is technically jadeite with too much iron, I will most likely not be able to feel the difference between that and a normal jadeite.

  I respect your knowledge on glass and will agree with you on that for an undamaged piece of glass. I also agree that you made me 1/2 as confident as before on my idea.

But, I don't think comparing oven door glass or Steatite to modern camphor glass is really an apple to apple comparison. Also, I think the bottles will get taken out, moved, touched, clinked and cork inserted/removed.

So, please do understand that I am not being stubborn, but just not fully convinced that modern tools and direction/speed of force applied does not have an equal or larger role then bad glass making.

Kind/Warm regards,
David

[Joey Silver / Si Zhouyi 義周司]

Dear David,
      I think both you and Giovanni are being 'devil's advocate' in response to each other's theses. This is very good, because it gets everyone to use their brains to try and figure out who is right.
      I agree with Steven that you can be a great asset to the Forum, with your ideas and 'Out of the box' thinking, as Giovanni is. I have a lot of empirical knowledge from studying snuff bottles for the last 44+ years, from age 13 (and you would be surprised at how generous with their time, knowledge, and even willingness to not compete at auction, tough older collectors can be, to someone who is much younger than them, and enthusiastic.).
      But you, Giovanni and Steven (as well as George and Charll)  have all sorts of tech skills I can't even begin to understand, which can help unlock mysteries dealing with WHY Tom's modern bottles are 'crizzling' themselves out of existence (I would have said 'cracking'; this sounds like cracking a lot more than crizzling to me.).
Best,
Joey
     

[Wattana]

I just realized I missed something... The drawers you are talking about is something special for storing snuff bottle? It controls temperature and humidity? Like a cigar humidor or wine cellar? Wow, that is interesting, you must be a very serious collector.

Hi David,
     No, the drawers are nothing that fancy! They are the typical office 2-inch high metal filing drawers, with tray inserts which divide the drawer into 12 cells, like specimen trays. This way you can get 12 bottles to a drawer. The idea is not mine. I once saw a snuff bottle dealer in London store his stock in this way, and thought it a good concept.
     To answer one of your other questions, the camphor glass / bubble suffused glass bottles are not noticeably thicker than plain overlay glass, in my experience.

Tom
PS: One thing I forgot to mention previously is that the camphor glass, apart from cracking, has developed an oily surface. This leads me to think that the glass is undergoing some kind of metamorphosis or chemical change, as Giovanni has hinted at.

[David]

Hi Joey,

Thank you for the compliments, I sincerely hope I can help.

I think crackling is a better term as this is way too fast compared to what the forum says about crizzling.

Hi Tom,

That is still pretty fancy, I just keep most of mine on the desk or shelves. It's funny though, the more I look at these tourist bottle that are fake hand drawn, the better they look compared to a real hand drawn (well... maybe real hand drawn, my confidence level took a few hits today) from a distance. But close up, the possible hand drawn ones looks better.

Is there more bubble in the camphor one compared to the clear bubbles? Or are they roughly the same?

How about the clear bubble ones? Do they also develop the oily surface?

The camphor ones, do they develop the oily surface first? Or did it turn oily after it cracks?

Is the oil surface thickening? Become more with time? Is it a oily surface that can be wiped off/scratched? Or kind of an oily look found on some old glass, but is just a sheen?

Does it smell?

That is so weird... 3 years shows sign, 12th year looks very bad (excuse me)... Did the oil look started recently or earlier?

[Fiveroosters aka clayandbrush]

Dear all,
it is an interesting discussion. Dear David do not be afraid of being stubborn, we all can be right or wrong and it is right to say our thoughts, either to be confirmed or contradicted.
About the origin of crizzling, the main point to me is: are there plain, blown bottles, which developed crizzling? If I am not wrong yes, and if so then it means that it is solely related to a problem of the glass itself. Of course any external source like high frequency vibration can accelerate the phenomenon. But surely not the action of the cork. Dear David, we have a long years tradition of bottling wine at home, something that I think does not exist elsewhere. In bottling the wine, the cork is inserted with a very, very big pressure. It seems unbelievable that the glass can take that big pressure and friction. Well those bottles are held down for generations, supporting many insert/take out of strong corks. I have never seen crizzling or damage of any sort. Frankly, I have never heard about crizzling before joining this forum.
Kind regards
Giovanni

[Joey Silver / Si Zhouyi 義周司]

I remember glass IPSBs from the PRC in the 1970s or 1980s which had an oily feel and a distinct vinegary smell.
Best,
Shabbat Shalom,
 Joey

[AntPeople]

Hi All

Have you all heard of this .....(Wiki Prince Rupert's Drops)

Prince Rupert's Drops

Prince Rupert's Drops (also known as Dutch tears[1]) are glass objects created by dripping molten glass into cold water. The glass cools into a tadpole-shaped droplet with a long, thin tail. The water rapidly cools the molten glass on the outside of the drop, while the inner portion of the drop remains significantly hotter. When the glass on the inside eventually cools, it contracts inside the already-solid outer part. This contraction sets up very large compressive stresses on the surface, while the core of the drop is in a state of tensile stress. It is a kind of toughened glass.

The very high residual stress within the drop gives rise to counter-intuitive properties, such as the ability to withstand a blow from a hammer on the bulbous end without breaking but explosive disintegration if the tail end is even slightly damaged.

Check out these YouTube

Mystery of the Prince Rupert's Drop - Smarter Every Day 86 Video demonstrating the creation, processes, explanation, and multiple high speed recordings of a Prince Rupert Drop.



Prince Rupert's Drop Video demonstrating the creation, strength, and explosive fragility of a Prince Rupert Drop.

Video showing the making and the breaking of Prince Rupert's Drops from the Museum of Glass

Popular Science article with video detailing Prince Rupert’s Drops

My 2 Cents

It could be that the Chinese glass manufacturing process was declining and also, at that time, lack of funds to purchase a annealing furnace or simply, poor process control. This does not allow the glass to cool in a more controlled fashion, thus giving raise to a higher internal stress within the glass...(although not as extreme as the prince Rupert's Drop)

Overtime, either bec of chips or tempt different or handling.... Crizzling/stress line/cracks starts to appear.


Pin

[David]

Hi Pin,

I think your 2 cents is golden! 

That is very very awesome, I never knew or thought there is such as thing. Do you know what happens if you keep such a drop for a few years?

Do you know if they can make a ball with no tail? Or a bottle?

What happens if you try to score it?

By the way, should I address you as Yee Pin or simply Pin?

David

[David]

Hi Giovanni,

Thanks for understanding 

After seeing Pin's video, I am moving a bit away from your theory  but, I want to think a bit more latter. I need to pick up the kids today.

I actually think the plain ones doe not suffer the same issue as the bubble one. Those looks like real cracks and not like the bubbles ones that looks like a hybrid of crippling and cracking.

David

[David]

arrgh! the auto correction keeps changing it!

crizzling

[Fiveroosters aka clayandbrush]

Dear Tom,
if I am not wrong you have plain bottles, I mean bottles that has not been carved, just blown, which are crizzled. Can you confirm that?
Giovanni

[Wattana]

Dear Giovanni,

Only my overlay glass bottles have cracked. I only have two plain glass bottles, neither of which are affected.

I do have some inside painted bottles which are also plain glass. they are all OK too.

Tom

Dear Tom,
if I am not wrong you have plain bottles, I mean bottles that has not been carved, just blown, which are crizzled. Can you confirm that?
Giovanni