Yep. I'd be interested to see how transparent beads would look before and after between a pair of polairsed sunglass lenses (my homemade polariscope).
With the temperature extremes (at least to our bodies), I'm curious about whether the stress would change the structure.

If someone requires this type of testing ... I think the problem is with the big bead that sits on their shoulders! This thread is hilarious!

I'd still like to hear from Mike why he posed this question.

As to an order for 10,000 beads, I discovered a long time ago that I get bored easily and that sort of production would be the kiss of death to the enjoyment I get out playing with fire and glass. Producing 10,000 beads by hand would be "sweat shop work" and it wouldn't matter what country it was produced in. I would pass.

Darrell

I’m gonna take one more shot at this. Though I’m really not sure why. I don’t have a dog in this hunt. I hardly ever make beads anymore. I make marbles, which sit in collector’s display cases and see very little stress, and murrine which is broken into chips sometimes even with a hammer, taken from room temp and plunged into molten glass or cut with a saw, ground down and polished. Just about the most extreme abuse any art glass can take. And I really don’t know this Grace Ma person. I’m only looking at the validity of the quality control test.

But I’m gonna start by putting on my history hat. Boring I know. When I started lampworking the big question of the day was “Do we even have to anneal?” The debate got pretty intense. Here are the arguments as I remember them.

Don’t anneal:
1 We make small things in glass. Our glass rods are routinely taken from room temp, plunged into the torch flame, cooled, and remelted. They aren’t annealed after each use. And they seldom explode.
2 People are going to subject beads to much worse that annealing won’t help prevent.
3 Glass beads from thousands of years ago weren’t annealed and seem to be holding up just fine.

Do anneal:
1 Lampwork in the US is a relatively new art form. It’s up to us as a community to set the standards.
2 If just a handful of artists don’t anneal it will cast doubt on the quality of all our work.

Okay, boring I know and the issue is long sinse settled. Of course we all anneal. But the discussion is the reason a lot of us still say “properly annealed” (though the test for "properly annealed" was never discussed) in our web listings. Then, being the artists that we are, we started getting creative with our techniques. Here are a couple I remember, each of which has the potential of weakening a bead.

1 The good old add baking soda to a bead trick. Soda, as in we’re working with soda-lime glass. It changes the chemistry and hence the COE. I don’t know what percentage of these beads survived. I can tell you I’ve only got one still in my case of old work.
2 Chek (spelling?) glass and the theory that you can add up to 5% of a different COE to your beads safely. This was a rule of thumb I never heard proved out or tested except by the then supplier.
3 Raku. I love raku glass, yes I still play with it, makes for great reptiles. But it’s not 104 COE. I think it’s 94. Anyway, again it induces stress.
4 Foreign objects, metal mesh, metal foil, CZs etc. Clearly these are not 104 COE

We’re artists. We’re going to push the limits. We NEED to push the limits. But we also owe it to ourselves and our customers to ensure what we sell conforms to the industry standards. Guess what? WE decide the industry standards. That was my point about the annealing question above. So what can we realistically expect a bead to endure? Again boiling water to ice water would seem to be most extreme we’d expect in daily use. I’ve spent the morning looking for every pair of sunglasses I can find in the house. None of them are polarized LOL. I’ll keep looking. But even if the test ended up inducing added stress to the bead (and therefore making it unsellable) it might be valid in proving the quality of the technique used for making the bead. I mean if our regular beads passed the test, but the ones with CZs didn’t I might seriously reconsider selling those beads.

But back to Mike’s original question and the 10,000 beads. Deanna recently got back from the Santa Fe show. A well know supplier of findings, tools, and even beads was asking around to various vendors about becoming suppliers. I suspect we’ve all used this company. I think we’d all be up in arms if it turned out the beads they were selling were of inferior quality. Of course they’re going to ask for some form of quality testing for such a potentially large order. You can focus on the competition, and always be looking at their rear end. Or you can focus on the opportunities.

I have no doubt that most round lampwork beads would survive boiling-to-ice. That's not my problem with the "test". My problem with the "test" is that, because the temperature extremes are wide enough to introduce stress, it doesn't actually "test" anything, and personally, I don't want anything that actually introduces stress to my work to become "industry standard".

Maybe the client has a non-jewelry application in mind. Perhaps using them as ball bearings in a fabulous, colorful Rube Goldstein machine, or gravel in a gorgeous garden.

If they pay enough, they can ask for whatever they want.

Hey, I radiation tested some of my beads just last week--wore a bracelet during a CT scan!
Lee

Thousands of Beads
 

These beadmakers have an opportunity to work with a designer who wants beads made in the USA. This is commendable!

I suspect that these beadmakers will be making money at a time when many beadmakers are struggling due to an economy that could be better....and will, but not by next Friday.

My involvement was only trying to help some artists out, and perhaps they might need some glass, and I got tons and tons.

Great replies, they made me think and made me laugh, and laughter is the best medicine.

Thanks Youj

Mike Frantz

My first inclination is to say, no you won't see any stress "frozen" in the glass. If I understand the physics properly any stress inflicted on the glass when it is below the strain point will go away once what ever is causing the stress is removed.

By alternately freezing and boiling the beads, you are performing more of a strength test than a stress test. Yes if there is stress frozen in the bead the addition of more stress may cause it to fail. I think a better test would be to make one or two clear beads, of the same size and shape, for each batch of beads that goes into each kiln and then check them with a polariscope, that way you are verifying the annealing cycle for each batch.

Just my $0.02

That's my understanding regarding induced stress as well. Though I do take Kalera's point that this should be tested.

So. Round small clear annealed bead. Tested with polariscope. Tested via boil-ice-drop test. Retested with polariscope. Would this suffice to validate the boil-ice-drop test?

And to the next question of if it's being polariscope tested why bother with the other test. I'd also like to see tested:
1 clear glass bead with raku on top
2 clear glass bead with raku encased
3 clear glass bead with copper mesh
4 clear glass bead with silver foil
5 clear glass bead with plunged CZ
My suspicion is that at least some of the above will show some stress under the polariscope. The boil-ice-drop test would indicate if some stress was actually too much stress. The follow up polariscope test again would be helpful to see if the bead could expect to see increased trouble down the line.

Yeah, yeah I should go run the tests. But I really don't make beads much anymore and have plenty to do already. And I don't have a polariscope, though I think I may need to pick up some polarized film. Maybe that should be included in new bead making kits (it's pretty cheap)?

Again, I'm just throwing this stuff out there. Personally I don't have a stake either way. Just my old job as a science technician asserting itself.

You are the man Mike!

Well I have found that goddess vessels will not survive a 3' drop to concrete!

I would think that the Goddess would get quite upset. :)

Who's gonna clean on the bead release.....just askin???

I fire mine from a cannon at castle walls!

Rofl!

Only AFTER 10 people advised the OP to use the search function before asking questions.....

If you do that to a Pyrex dish, you're probably going to break it. If you do it to any kind of glass, you might break it. It's such a stupid test that proves one thing - Don't be stupid and subject GLASS to extreme temperatures.

I would be more worried about the beads after they were subjected to such treatments!

Boiling water is 212 degrees F. Ice water is 32 degrees F. A difference of 180 degrees F. This would be comparable to taking a glass dish out of the oven at 250 degrees F into an ambient room temp of 70 degrees F. Personally I usually do my baking at considerably more than 250 degrees. You are not going to break a pyrex dish at a 180 degree difference. Look at the Visions/pyrex advertisement. It shows a glass bowl/pan directly on a blue flame. We all know a blue gas flame is one hell of a lot hotter than 250 degrees. I'd hazard a guess at closer to 750-1000 degrees. And that is a localized heat on only one section of the pan while the rest of the pan is closer to ambient. The stress is between the hot and cool sections.
Now if the test in question required that half the bead be subjected to boiling water while simultaneously the other half was subjected to ice water you might have a point. But that's not the test. The test involves uniformly heating a relatively small amount of glass (relative to a glass pan) to a rather mild heat (212 degrees) then uniformly cooling the bead to 32 degrees. Any glass should handle this amount of stress. And as I've stated, I've run this test myself on my beads with no problem. And though Kalera has a point that induced stress needs to be tested, I highly doubt there would be any trapped stress below the soft glass stress point of 870 degrees F.
Do a google search on Visions/pyrex cookware problems. Most of the problems, way under 1% of the total cook ware out there, is attributed to flaws in production. The rest attributed to abuse of the pan. And even then we're talking about extreme temperature variations repeated over the course of years. Not one single isolated test.
I have no problems with Kalera. I know her work to be of the highest quality. She's been in this art form long enough to know what she's talking about and I respect her opinion and concerns. But it's this type of answer that riled me up in the first place.
I'm outside in winter. It's negative 10 degrees. I walk into a hot building at 80 degrees. This is a 90 degree difference. Extreme I know, but possible. It's not unusual for product testing to be 200% of normal expected usage. This would equate to 180 degrees or basically the test in question. This is not an extreme test.

Oh, I stand corrected. I thought we were talking about putting beads into boiling water, and then plunging them into icy cold water?

Of course, I know that there is a difference between taking a Pyrex baking dish out of a 350 degree oven and putting it into cold water in a sink vs. 212 degree hot beads plunged in icy cold water. But my point is the same. It's glass, and adding stress to it does not prove a thing except you're taking a chance on compromising its durability. BTW - I have shattered a glass Pyrex measuring cup that I took out of the microwave and poured cold water into it too soon after dumping out the hot. Every piece left of it with exception of the handle was about 5-6mm or less. I couldn't believe it.

I would never feel comfortable selling beads that got the hot-cold treatment. I would keep them around for a few years to see if they break. Hell, I've kept beads and never sold them after they took a hard bounce across my concrete floor! Which is why I have two large rubber mats in my work are where I clean, inspect, and prepare beads for shipping.

I dunno. I still think it's a whole lot of extra stress to re-introduce post-melting/annealing.
The most rigorous testing mine get is cleaning/dremelling and etching before batch annealing.
Then I test the control beads I make with transparents post-firing for any remaining stress from melting. If it's present, they don't get used. If it isn't, that's good enough for me.

Surely simply choosing a glass and establishing that it will withstand the conditions first up, then checking for any stress signs before despatch is sufficient?

One thing I have learned in my short career as a glassmelter, is that it is just as easy to 'unanneal' glass as it is to anneal it.

Having said all that, congratulations on such a big order. That's wonderful. However, no matter how well - made a product is, someone will always do something to push the boundaries of durability, reasonably or otherwise.
I think there has to be some kind of message to that effect, even a disclaimer. A reminder that glass is glass can simplify things no end.
All the very best with the venture :-)

212 degrees is the boiling point of water. No matter how high up you turn your stove, boiling water will remain at 212. The extra heat just makes it boil harder, not hotter. Just as ice water is 32 degrees. Water is just a really weird substance.

The most rigorous test mine get is being banged around in my handbag

Dude, I want that order. I'll test them if that's what it takes. :D

From Arrow Springs. In short, glass will not retain thermal stress below the strain point (around 840 for COE 104).

http://arrowsprings.com/html/annealing.html


"The cooling of glass is most important between the annealing temperature and the strain point. As explained, glass will develop stress in itself through the cooling process. The strain point is a point in temperature at which any stress that develops below that temperature in the glass through the cooling process is only temporary. Stress that develops in the glass above the strain point is permanent. Once the glass has stabilized to room temperature, temporary stresses will disappear. Because of this fact, you can accelerate the cooling time below the strain point temperature and not worry about this strain causing the glass to break at some time in the future. However, cooling at too fast a cooling rate can still break the glass from thermal shock while still in the annealer. The strain point for glass varies between manufacturers and even between different colors from the same manufacturer. If you use a temperature well below the strain point of all the glasses you use to cool slowly down to before then increasing the cooling rate, you will not need to know the exact strain point temperature of each individual glass. Use 750º F for Satake and 800º F for every thing else."

That's what I've been wondering all along! If we anneal at some temp above the strain point (being at the very least greater than 850 F for Effetre) does the variation between 212 F and room temp or Really Cold (ice water) really make a difference? Proportionally, my guess would be NOT. Maybe, if there were already significant stress in the glass, it might pop. Otherwise, I've been doubtful since I first learned about these testing notions. I feel even better, now. (But I've spent a godawful amount of time with statistician-types, where even the smallest +/- made a difference, let alone the Sacred Standard Deviation. LOL)

In other words, if a bead is properly annealed at whatever the particular temp (>700), would a temperature "test" between 212 and 0 F even matter?

That was why I suggested the addition of clear beads the same size and shape in each batch, that would confirm that the annealing cycle was executed properly. The freeze/boil test, would be more of a structural strength test, is the shape of the bead strong enough, do any dots/prunts come off. As artisans we want to ensure the highest quality of work, but we need to make sure that our testing methods are equally of high quality and that we are testing what we think we are testing. I'm sure there are some charts somewhere that could be used to calculate how much stress is caused by alternately freezing/boiling a piece of glass. Let me look in my copy of Bandhu's books.

I keep remembering when we were kids, and would put marbles in a hot skillet then dump them in ice water because we wanted them to get all the fracture lines in them. And now if that happened I'd be so upset, LOL!

Sorry for the interruption ;)

I also ran across this chart from Corning. It's more technical and easier to misinterpret, but interesting. They list the normal working temperature of soft glass as being 230 degrees (a little more than boiling water at 212), meaning you can take glass to this temp as fast as you want. The extreme working temp. is listed at pretty much the strain point. They don't talk about the lower end of the temp scale for normal working temp.

The part where it gets confusing is the thermal shock tests. They list much lower high temperatures, though they are working with larger pieces of glass (15cmx15cm by varying thicknesses) heated and plunged into cold water. Though otherwise the test starts to sound a lot like what we're talking about here.

http://www.quartz.com/pxtherm.pdf

Okay, the freeze boil test is a simple that that can be performed by almost everyone, with no special tools, but it does not yield a quantitative result. Drawing on my experience as an industrial QA technician/engineer, wouldn't a better test be to place one of the afore mentioned clear beads into a bench press with a calibrated strain gauge, and then see how much force (pressure) the clear bead can withstand before failure? Just thinking out loud here.

ETA: Okay, I've probably way over thought this, way beyond what Mike originally asked.

Would you open you kiln when it reached 212 and take out your beads? I wouldn't (let alone plunge them immediately into cold water). And if I did and they cracked I would consider it thermal shock and not inherent stress in the glass.