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Charles Willis 10-06-2019 01:31 PM

I'd like to thank everybody for their input. This situation has just taken an interesting turn. My partner called to tell me that one of his recent pieces exploded while sitting on the shelf. He was using Reichenbach for color. We'll be having a conversation with the studio manager about this. If we ever figure it out, I'll post back.

Pete VanderLaan 10-06-2019 02:46 PM

It's figured out.

Sky Campbell 10-06-2019 03:20 PM


Originally Posted by Pete VanderLaan (Post 145454)
It's figured out.

The sarcasm is priceless.

Rick Wilton 10-06-2019 04:14 PM

You can see stress in glass with something as simple as your cell phone and a pair of polarized sunglasses. It's really NOT that hard.

Pete VanderLaan 10-06-2019 05:04 PM

well, I agree. It's still helpful to identify the source though. Some of this is no longer rocket surgery. While I don't want to beat up on the folks just realizing these issues, there really are a lot of sources which should have put them on to it sometime back. There's really nothing new to see here. In this instant world, that should not be.

Greg Vriethoff 10-06-2019 05:30 PM

You don't have to distinguish between sheet and blowing nuggets when you're talking about Sys96. It's all the same failure.
I still maintain the "99 COE/LEC" should be confined to the nugget debacle.

Pete VanderLaan 10-06-2019 06:22 PM

That well may be true but if it is the case, it strikes me that the big sales pitch regarding the sys96 colors would be drop dead easy to match to the clear. That was the point.

If what you say is true, and the two are different, is it the case that the colors matched both glasses? One was measured at a 94.1, the other as you suggest is a true 96.

They should not fit each other if that is true. I do view .5 as a lot.

Terry Crider 10-06-2019 08:02 PM

This question is a little off from the rest of this thread, but it's might be of interest.
In the late 70's Frank Fenton gave me a list of exp. numbers a lot of their colors.
The test temp. range was 0-300C degrees.
Do have any idea how much difference there would be between this and the temp. range you use ?

Pete VanderLaan 10-07-2019 07:36 AM

300C is the gold standard. I would note that the testing I've done has been from 19C though. Getting your samples to stay at 0C is quite the chore. When Los Alamos labs did the testing of my dilatometer with me back in the late '90's, we did ice water baths with magnetic stirrers to try to get the tooling down to 0C and the numbers never made sense. It wasn't until the temperature that people in lab coats like to work in that we tried 19C and it all worked well and made sense. It's an important observation in that the testing Winkleman and Schott did for the enamel industry only went to 200C which was why the combination of those numbers with the English and Turner numbers failed. It's really the case now that the Appen figures are the best.

The dilatometer is not used much in the studio. John doesn't use it and I tend to if I know absolutely nothing about the glass in question. Otherwise the Hagy seal and the ring test provide excellent comparative numbers, one through gaps and the other through tension. Both ring and Hagy are problematic if the test glasses are off by much. They break. My goal in any test is to have all the indicators pointing in the same direction.

At that point viscosity becomes an important factor. The piece in question is I'm sure chock full of different ones.

Shawn Everette 10-07-2019 12:54 PM

It doesn't really make sense for spectrum to design a blowing nugget(system studio) to be used with their flat glass line, and then make a better blowing glass(system premium) not deigned to be used with their flat glass, yet to have the flat glass coe closer to the better glass.

If the flat was a true 96, then nearly everyone using cullet, including Charles, should be able to use it. Not to mention most of the people using spruce.

I've had 0 problems with the studio nuggets and the flat glass. I've gotten away with the premium and flat sometimes, but there were colors that wouldn't take.

Pete VanderLaan 10-07-2019 04:11 PM

How one melts makes a difference and it's not insignificant.

Back when I had the little studio in the Santa Fe railyards, I would melt on sundays and one pot was 275lbs of my clear and another was a 75 lb of a copper ruby. I would work both of those pots until midweek when at the end of the day, I needed more red, but the furnace was running at 2080F which is where I liked to work. I did actually want to go home so starting that cold, I loaded the red pot full of the batch glass. I did not return usually.

Now it's important to recognize that the red glass came out of the same batch barrel for both the sunday and the thursday melts. No changes. Identical mix from the same mixer.

The next day, I would use both glasses and the red was no longer compatible with the clear. This occurred several times before I started to dig in and change my process. If I turned the furnace up and waited until it was at least 2250F, there were no issues. It became clear to me how sensitive batch melts are looking at expansion/ temperature ranges.

The point there is that the two glasses are or were being melted in rather different environments, the big melter at Spectrum undoubtedly hotter than the Uroboros furnaces. It's worth considering. I don't ever try cold batch melts anymore unless they are fluorines with far lower viscosities.

Shawn Everette 10-07-2019 04:40 PM

I have no doubt that the way the nuggets are treated is remarkably different, or that the formula is tweaked from the base clear, I've melted the flat scraps. Just doesn't explain why system "96" sheet glass would be compatible with system "96" base cullet, with it's measured coe of 94, and not also be 94. If the sheet is a true 96, then why is it compatible with a 94, but not all the other 96 out there?

Sky Campbell 10-07-2019 05:06 PM


Originally Posted by Shawn Everette (Post 145480)
I have no doubt that the way the nuggets are treated is remarkably different, or that the formula is tweaked from the base clear, I've melted the flat scraps. Just doesn't explain why system "96" sheet glass would be compatible with system "96" base cullet, with it's measured coe of 94, and not also be 94. If the sheet is a true 96, then why is it compatible with a 94, but not all the other 96 out there?

The sheet glass was measured to be 94 not 96. The original studio nuggets was compatible with that sheet glass. The last spruce pine clone made by spectrum was 96 some colors work some will not. That is in my experience and testing from a trusted source.

Pete VanderLaan 10-07-2019 06:21 PM

Best not to sell the pieces made from it. If you do, they'll break for sure. If you make some butt ugly stuff with it, it will last forever.

Greg Vriethoff 10-07-2019 06:35 PM


Originally Posted by Sky Campbell (Post 145481)
The sheet glass was measured to be 94 not 96.

Okay, Sky. Thank you for answering my question.

I'll stop questioning the irrefutable truth.

Shawn Everette 10-07-2019 07:30 PM

Ok, that's kinda what I thought.

I was able to get away with several of the cool colors with Premium 2.0, but not much in the warms, it hated adventurine.

We ended up getting into an ugly argument with a guy that wanted to stiff us on a bill because "our glass was bad". I told him at the beginning of his blow slot that the two weren't guaranteed to fit, though of course he knew more than me. He was one of the ones that 30 years of stannous ate his brain. Sure makes shit shiny, but I like maintaining the level of crazy I currently have.

Sky Campbell 10-08-2019 01:02 AM

Greg please understand I went through tons of the original formula with tons of system 96 color. Never a problem beside coe shifts from holding color in the pot to long or to hot. Iím still melting the sp clone and still have buckets and buckets system 96 color. As much as I want them to fit they donít. Iím left with now 350 lbs of original studio nuggets that I strictly use for dicro (coated on system 96 sheet) with aventurine and other system 96 colors. Same weights will explode if made with the clone, cristilica or clean 96 batch. This is my real world experience. It was tested by two people I respect in the community and reported to be 94.1. I understand that goes against what you believe to be true but to me explains the loss of a s-ton of work in the annealers and my inability to make these glasses fit. I donít know what else to say but maybe spectrum measured differently. There are different ways to calculate coe of glass.

Shawn Everette 10-08-2019 07:14 AM

I second this, verbatim.

They may say it's a 96, but it goes against experience, and logic. That, or everyone else is wrong about blowing batch, cullet, and color being 96.

Pete VanderLaan 10-08-2019 07:27 AM

94.1.. and it's L.E.C. and aventurine.

Michael Ahlefeldt-Laurvig 10-08-2019 04:31 PM

Just use Glasma and be done with it all

Greg Vriethoff 10-08-2019 05:45 PM

I won't argue with anyone's real world experiences.

Original studio nuggets are 94.1. Use this with sys96 sheet glass and things are okay.

Ergo: Sys96 sheet glass is also 94.1

Not the number I ever saw numerous times under a polariscope.

But what hell do I know?

I was stupid enough to go to art school instead of the school of hard knocks.

So I understand now. Be sure to test for fit... unless it doesn't explode and fits your agenda.

My last words on the subject: Correlation does not imply causation.

Pete VanderLaan 10-08-2019 05:48 PM


Originally Posted by Michael Ahlefeldt-Laurvig (Post 145496)
Just use Glasma and be done with it all

Actually, that won't work either. If you extend your color demands to materials produced all over the globe. you will hit mismatch. Why, realistically, if you believed in the physics, would you expect otherwise?

Shawn Everette 10-09-2019 09:31 AM

So what are you testing this against that is pointing it towards a 96 rather than a 94.1?

Sky Campbell 10-09-2019 10:41 AM


Originally Posted by Greg Vriethoff (Post 145497)

Not the number I ever saw numerous times under a polariscope.

Do they have a polariscope that gives a number reading or are you referring to a dilatometer? If itís a dilatometer then itís very possible you used a different tempature range to test in which in return will give you different numbers.

Pete VanderLaan 10-09-2019 10:47 AM

I have read both SP87 and my own clear on a dilatomoter and SP87 has really been remarkably consistent over the decdes. I engineered my clear to match SP87 at Tom's initial request and it sits dead on. Using the clear cane from SP87, which I've harversted over the years and kept each harvest with notation, that was applied to Hagy seal testing of other glasses. Both John C and I took the same approaches and found the retardation of light to indicate a 94.1 on the Sys 96. That was coupled up to a ring test done using the SP87 and the glass in question. In that case, I could not achieve any result without breaking the sample using a saw and had to do a live ring test getting the sample off a hot blowpipe which is a good trick but it works. Even the Hagy seal is dicey given the mismatch. In no event could I get the ring test to survive on the saw which is a major criterion for reading the mismatch. Anything over about 1.8 has issues.
So, I like my indicators all pointing in the same direction and they did, the dilatometer being the one that does not compare, it just measures. I normally run a dilatometer three times in testing with a fresh 4.000 sample in each run. I do that from 19-300C. The tool is made of quartz with a quartz pushrod. The cane is meticulously kept at 4.000.

Finally, you can see the results in blown ware as well as paperweights. Pieces break up. It frequently happens when the surface tension is messed with. That freqently occurs with opaque color rod as well when sawn. That's telling. At 1.5, they don't unless there is some other issue, thickness being one.

After doing it for decades, you get to where you can see what's up.
I have really never thought that Spectrum tested or really cared about field measurements. How a company could make two clear glasses, incompatible with each other was always rather telling to me.
I have never cared for the methodology used at Uroboros to read strain. It's a pair of slide sized pieces laid side by side and fused together and then read in a polarized screen. I do get a great sense of mismatch if the glass in question is melted inside of a clear chunk. That glows but I can't convert that to an actual number.

I don't spend my time on this stuff these days. When I was making rod, I did. I don't mind throwing rocks from off in the corner though.

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