Cristalica and Reichenbach opq

[Shayna Leib]

I'm having some issues with a Reichenbach yellow (krongelb) and Cristalica, which I'm trying for the first time in my moly furnace.

Years ago, don't remember the exact year, Gaffer was having issues with its taxicab yellow when China raised the price of one of taxi's key ingredients and it went from an orangish yellow to a fluorescent neon yellow overnight. Perhaps some of you remember that. It messed with my work so I bought about 3K worth of Reichenbach krongelb to use as a base opaque with layered cane, using both green or red over the yellow to give depth. I was using System 96 nuggets and despite deplorable working times, those were happy days of being a kid in a color candy shop and using just about any color I wanted. A far cry from the 90s when you had to test every dang bar.

So for years, I used System 96, then Spectrum 2.0 without any color compatibility issues. I decided to try Cristalica since I had to invest in a new crucible anyway. I'm now getting splitting when layering a transparent gaffer over the Reichenbach krongelb. RIGHT. DOWN. THE. MIDDLE. But only with thick cane 15mm +. Not with pencil sized cane. That remains ok. I ruled out annealing issues, putting away too cold, etc. so now I suspect the yellow, or the combo of a gaffer transparent over Reich yellow (never a problem before). After about an hour's worth of research on the board, the yellow seems the most plausible since the general consensus is that gaffer color works with Cristalica.

1. Thoughts?
2. What are people's experiences with Bomma and specifically Reichenbach compatibility?
3. It also appears Cristalica is 100 COE. They say the "theoretical COE is 96" but the "actual" is 100. WTH? I don't remember seeing theoretical vs actual in glass terms. Perhaps that is some new jargon that people like me who live under rocks haven't experienced yet...

This is what I get for trying something new and not doing trident tests....

[Pete VanderLaan]

Cristalica is, I believe about a 97 L.E.C. SYs96 is still actually a 94.1. Spectrum 2.0 was a clone of Spruce Pine but had various production processes in which it varied. Spectrum sold it's formulations to Oceanside which only produces the sys96.

In most color rod formulations, they have about 24% lead which allows for a higher level of mismatch with clear base glasses within limits. Since Cadmium reacts in a very negative way with lead , creating a shit brown glass, you can't use lead making those colors. Since they have no lead, the tolerance range maximum is about 1.5 x 10-7th which creates issues.

I doubt it was the acquisition of any chemical in China that caused the issue back then but more likely something that Gaffer did to change the presentation. John was very conscientious about mismatch but the company has had some issues trying to be one size fits all. It's very hard to do. The longer you work cadmium or selenium based colors, the more likely that it will change expansions while on the pipe. Splitting right down the middle suggests possible annealing issues to me.

Bomma matches the SP87 most closely when it comes to expansion and that would probably help you out. Changing cullets for desired production results is a dicey thing to do. Based on what I know, Cristalica is not just high on expansion if you view SP87 as the gold standard, but the level of boron is unacceptably high and will dissolve your furnace more rapidly.

I can't speak to the Reichenbach. I don't use color rods. I just do the testing. I don't necessarily think there's a consensus about cristalica fitting gaffer. Some stuff fits, some doesn't . Testing is still your best friend.

[Pete VanderLaan]

Originally Posted by Shayna Leib

So for years, I used System 96, then Spectrum 2.0 without any color compatibility issues. I decided to try Cristalica since I had to invest in a new crucible anyway.

*****
So, in a nutshell, here's what bothers me about your logic. Sys96 worked if I understand you OK. So did Spectrum 2.0. So, it appears to me that you switched to Cristalica and began having troubles although you seem to want to blame the color, not the clear. Logically that does not make sense to me. I'm simply unaware of any consensus that most Gaffer colors fit cristalica.

Having dealt with the company and having read all their literature, I think they would like to be all things to all people. Cristalica is used more in the EU.In general, the EU glass workers have a slightly higher expansion expectation than they do here in the US.

I think you could go to Oceanside which I view as risky, you can go to Bomma and the jury is really still out there, or you could use SP87 as a batch. Gaffer did model with the assumption that SP87 was the target clear.

[Josh Bernbaum]

Shayna, to narrow it down even further, you gotta do some more testing it sounds like to me. What I didn't read in your post was whether you tried just this Reichenbach opaque yellow alone, without another transparent color on top of it. And are you annealing this cane in which you're seeing the splitting? Do you have any leftover cullet from the System 96 or Spectrum? If so, you could heat up and incorporate that with some of the color in question, and try to saw through it after annealing. Then compare the results to the same testing with the same color and the Cristalica you're now melting. Fluorine yellows are tough, and in my work where I do a lot of cutting through color layers after the work is annealed, I can only expect so much out of the opaque yellows, even from Gaffer.

[Pete VanderLaan]

Back up here. The yellow gets cased in another transparent color rod?

When does it split in half exactly? Is it rolled into the clear and melted in? Or, is it cased in clear as just a rod? Is this yellow cased in green cased in clear? Does the whole thing split in half, what? Does it get pulled in tension?

[Pete VanderLaan]

Another observation:

When Peet Robison was still alive he used to do this very simple test for mismatch: He took a gather of clear, cased it in the color in question and then
cased that in the clear again. If it was incompatible, it fractured on the spot.
It seems to me that it worked every time. You did not know which way it failed but you sure knew that it had.
The trouble with Hagy seals was always that if they were very far off at all that the seal fractured any didn't have a clue. Ring tests blew up. That in turn was the point of doing the dilatometry. It just told you what it was.

You need all the clues pointing in the same direction. Seals, Rings, pull tests. That's what I taught. Nothing will tell you the whole story.

I do miss Peet. I miss Henry too.

[Shayna Leib]

Originally Posted by Pete VanderLaan

Back up here. The yellow gets cased in another transparent color rod?

When does it split in half exactly? Is it rolled into the clear and melted in? Or, is it cased in clear as just a rod? Is this yellow cased in green cased in clear? Does the whole thing split in half, what? Does it get pulled in tension?

Hi Pete! And Hi Josh!

To be a bit more specific with the veiled cane, I start with straight bar stock, gather clear, wrap a transparent like gold ruby or emerald green around it, gather a final time and pull. Often, I will take the ends of the cane pull and box them as is, with their diameters being roughly 10-25mm. They get a gentle bend, a deep long flash, and put in the annealer. It's these ends that I'm talking about which are cracking down the middle. See attached pic of a cane landscape with larger cane "ends" which get polished.

To complicate matters further, it does not appear to crack with veiled POWDER cane (yellow rod, clear, powder, clear), only with the Gaffer rod overlay. When searching through the archives, I think Josh Bernbaum or possibly David Patchen plus a couple others claimed that gaffer seemed to fit Cristalica so I'm looking to the Reichenbach yellow instead. It's always in the back of my head that the more you play with the opaque yellows, the more finicky they become.

Both the regular cane and the thicker cane pull ends go thru a double heating. Cane gets air-annealed, then slumped over molds and re-annealed. Those ends that cracked get reheated exactly one time (the final flash) before being boxed. I'm boxing those ends so hot, they come out of the kiln covered in frax or kiln shelf on the side they're resting on. I double checked my annealing point and annealing cycle. All good there. After a couple of observations today in the studio, I'm really suspecting the Gaffer overlay, or the fit between all the layers, though the clear has a way of making sure everyone plays nicer.

Cristalica is not my favorite for many reasons so far. Lowest on the list of all the cullets. Despite the fact that the yellow is the easiest to scapegoat, Cristalica is getting all my cuss words whether I blow, pull cane, or solid work. It appears brittle, working time seems closer to System 96 at times when it's thin, and it's almost as if the annealing and strain point are a few degrees off of each other. It's a strange glass.

[Shayna Leib]

Originally Posted by Josh Bernbaum

Shayna, to narrow it down even further, you gotta do some more testing it sounds like to me. What I didn't read in your post was whether you tried just this Reichenbach opaque yellow alone, without another transparent color on top of it. And are you annealing this cane in which you're seeing the splitting? Do you have any leftover cullet from the System 96 or Spectrum? If so, you could heat up and incorporate that with some of the color in question, and try to saw through it after annealing. Then compare the results to the same testing with the same color and the Cristalica you're now melting. Fluorine yellows are tough, and in my work where I do a lot of cutting through color layers after the work is annealed, I can only expect so much out of the opaque yellows, even from Gaffer.

Josh,

I replied to Pete with a more detailed explanation. I think it'll make more sense after that. Check it out. The veiled cane (yellow, clear, transparent Gaffer overlay, clear) is cracking upon sawing. However, POWDERED veil cane (yellow, clear, POWDER transparent, clear) is not. I mentioned to Pete that it's almost looking like the Gaffer might be the problem, which was not really on my radar. But if I read the signs....

[Pete VanderLaan]

Think on this " If A fits B, and B, fits C. It does not follow that A, fits C.

Greens are something you mentioned. They inevitably are made with chrome. Inevitably, chrome is problematic, and so is cadmium. Veiling is relative to how intensely you veil. Thin= potential tolerance, Thick, maybe less so. I love diamond says . They talk like a virus talks.

Gaffer in itself is not a problem but the combinations can make one. I did not ask about tension casually. Lino used to show me strange issues about how the cane was cooled. None of it is annealing. Tension is the way glass breaks, not compression.

If the green fits the Cristalica and the yellow fits the Cristalica. then go back to what I said in the first sentence. Reality suggests ""Fits" is more like "tolerates".

Don't make "tolerates" . Time will tell you when it's a bad idea. I have some slugs of color laminates here that I made about 20 years back. I had one break up about a half year back.

Glass will lead you to humility. All of this is why I encourage people to make their own color, an utter waste of my time apparently.

[Josh Bernbaum]

I don't know anything about the Cristalica, so maybe that was David who had mentioned something about the fit with Gaffer. I'm mostly only familiar with SP batch, and the colors I've made myself. I've even made lead-free fluorines that fit the initial ring test well, but then the fit went kaput after 2 reheat cycles (murrini). Seen the same with Gaffer fluorines. Even talked with John about that once and it sounds like we are just at the mercy of physics and chemistry sometimes. Or all the time.. So I'm surprised to hear that the fluorine yellow might not be the culprit here. But maybe the chrome in the green, as Pete suggests, could be the issue. I imagine Gaffer make that in a base that contains lead though, so it should be less suspect than an opaque yellow. Here's the test to rule out the yellow if you haven't yet: make the same thing, same steps, same heats, same everything except only use the green transparent in the same way with no other color in the cane. See what happens. If it survives annealing, then saw it and see what happens then if you really want to know what the fit is like. Keep us posted too, I like hearing how these issues turn out or get resolved or not.

[Eben Horton]

Crystalica is a proven furnace destroyer. Consider switching to Bomma for that reason alone.

As far as your color issues go.... it seems to me that if I had this problem, I’d find another color.

[Pete VanderLaan]

Do not disregard if A fits B, and B fits C, it does not mean A fits C.

[Shayna Leib]

Originally Posted by Josh Bernbaum

I don't know anything about the Cristalica, so maybe that was David who had mentioned something about the fit with Gaffer. I'm mostly only familiar with SP batch, and the colors I've made myself. I've even made lead-free fluorines that fit the initial ring test well, but then the fit went kaput after 2 reheat cycles (murrini). Seen the same with Gaffer fluorines. Even talked with John about that once and it sounds like we are just at the mercy of physics and chemistry sometimes. Or all the time.. So I'm surprised to hear that the fluorine yellow might not be the culprit here. But maybe the chrome in the green, as Pete suggests, could be the issue. I imagine Gaffer make that in a base that contains lead though, so it should be less suspect than an opaque yellow. Here's the test to rule out the yellow if you haven't yet: make the same thing, same steps, same heats, same everything except only use the green transparent in the same way with no other color in the cane. See what happens. If it survives annealing, then saw it and see what happens then if you really want to know what the fit is like. Keep us posted too, I like hearing how these issues turn out or get resolved or not.

Will def keep you posted. I tend to like puzzles like this, deductive ones. The problem is not just the green. The same is happening with gaffer gold ruby over that yellow. So it seems, in part that either gaffer or the yellow is the common denominator. Though yellow alone seems just fine! That makes me agree with Pete, it's like they don't quite all fit together. More like if green fits clear and yellow fits clear, it doesn't necessarily follow that both green and yellow fit clear at the same time, together. Same with the gold ruby.

It's funny to be back here, after 10 years of having a stable color palette. You're never too far along to go back to basics though.

Seriously considering trying Bomma. Seems more stable according to all the posts I've read.

[Shayna Leib]

[quote=Pete VanderLaan;149382]Think on this " If A fits B, and B, fits C. It does not follow that A, fits C.

Agreed. The transitive law doesn't necessarily work. That is the strongest explanation so far. It's very curious though. At this point, it's a puzzle and I'm intrigued and stubborn enough to want to pinpoint it. Tomorrow, I'll pull just transparent green or red cane like Josh suggested just to see what happens.
By the way, it's the gold ruby, too.

Having something fit for 20 years and then hearing that "ting" is my worst nightmare. Ugh.

[Jordan Kube]

Your process isn't going to be as forgiving as just blown pieces. You're creating a lot of weak geometry with the slumping and fusing.

[John Croucher]

In all our testing at Gaffer the only glasses that are problematic fit-wise with repeated heating are fluorine opals with cadmium in them. Transparents with CdS are fine and fluorines without CdS are OK also. It is the combination of a fluorine opal matrix with CdS or CdS.xSe nanocrystals that is problematic with repeated heat work. The temperature zone that is critical is somewhere between 1300-1500oF. Around fusing temps.
The F + CdS combo increasingly densifies, compacts, shrinks with continued cycling through that zone to the point where mismatch with other glasses will lead to cracking. It is quite radical really -LEC shifts must be at least 3+

Note that Bullseye recommends a limited number of fusings for this family of glasses. If one insists on multiple reheats through the fusing range with an opal red and yellow appearance then I'd recommend say opal white with transparent yellow or red overlays.

[Pete VanderLaan]

John always good to see you lurking.

try thinking about what makes a fluorine opal work. Initially you need the fluorine but it also needs either calcium or alumina to make the crystals. Those crystals are very active in the range John describes. They grow, they collapse and they grow yet again but with a little less insistence as the process ages. Don't dismiss the sulfur in that yellow either. That ultimately affects both the expansion and the viscosity of the glass in question.

Going into the way back machine, Mark used to make these pieces that he insisted were compatible when he started them and seven hours later, were no longer compatible. I don't doubt that for a second.

If "A" is 94.1, it can fit "B" well enough up to about 95.6 which in turn can fit another glass "C" on the outside of 97.1.
But 97.1 won't fit a 94.1 at all. That doesn't even consider viscosities.

I've measured Cristalica at above 97. How they claim it's a 100 I can't accept on peer review. This isn't even considering viscosity but Danny would be all over it.

And there's always the weird and unexplained. When you pull cane, if you hold it rigid as it cools, the rod is in tension. Tension is how glass breaks. It doesn't explain anything but it is another factor in the mix.

[Pete VanderLaan]

try this: Peet used to do it:

Make each cane, one the yellow cased in clear, one the green cased in clear , one the yellow cased in the green. another with the yellow cased in green cased in clear.

Put them on the marver cold and then allow an ample amount of really hot clear to cover them. Tell me what happens


The other thing that is easily revealing about compatibility in cane is how well does the cased cane cut. If it's a clean break using a nipper, it likely fits. If it's a crunchy crumbly experience, It likely won't and it's talking to you

[Scott Novota]

these are always my favorite threads.

[Pete VanderLaan]

me too Scott. They used to be "all the time".