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Old 11-16-2020, 06:57 PM
Ryan Turner Ryan Turner is offline
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Why are there so many soft glass COEs?

I've been working soft glass for a long time and just realized I can't actually answer this question. How did they come about? Is 90, 96, 104... just an accident of history, or is there some particular reason why these COEs are most suited to their common applications?
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Old 11-17-2020, 11:11 AM
Shawn Everette Shawn Everette is offline
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It's most likely a result of manufacturers creating a base glass for specific applications. 90 is a great fusing glass, but garbage to blow. 96, depending on source, can be a good for fusing or blowing, but rarely great for both. 104 was designed for lampworking when you still had to pump the bellows yourself. There are always exceptions, but that's probably it in a nutshell.
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Old 11-17-2020, 11:14 AM
Art Freas Art Freas is offline
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"90 is a great fusing glass, but garbage to blow" Very true, I took a rollup class and we used bullseye 90 for the rollups and then blew them out. You had to heat like you were going to spin it out and then work it quick like it was a goblet. At the time I was used to the short working time of the Sys 96 Studio nuggets so I was passable at it. The folks that were used to the longer Spectrum Premium 2.0 were not having fun at all.
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Old 11-17-2020, 02:23 PM
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you should go look at a thread in Antiques and classics about the beginnings of the term COE which as I recall originated at CR LOO in the mid '70's. The thread was started by Lani MacGregor from Bullseye.

The early glasses in use were John Mansville marbles which Nick Labino brought to the Toledo workshops in '62. "Brutish and short", but they could be melted and they were the mainstay for a number of years before other cullets like Keystone and Gabbert found their way into school shops. No one really realized that Gabbert was the collator of the W.Va factories.

Why the W.Va factories were never considered as a knowledge source by the Littleton/Labino workshops to me was a strange arrogance of an existing resource or I at least think that now. It took a long time to realize that these guys knew an awful lot about making glass but since thrust in the schools at the time was ART, one person/ one piece, it wasn't going to be the case that the schools might ask for help. Even as Joel Phillip Myers who designed for Blenko became acceptable in the collegiate scene, you didn't talk about Blenko.

By the mid '70's there were more than a few of us making our own glasses but it was a minority. Private studios were coming on- the schools had great disdain for them and largely turned their backs back on that branch of the tree. When we issued the invitations for the Hot Glass Information Exchange in 1977 ( I think) Those invitations went to every school. Only Andy Billici took it seriously at Alfred and submitted a paper. Marvin came as well but then Bingham threw him out since he did not have a contributing paper for admission. There were no other schools.

We were still having issues nationally with standards. In '74, Bullseye made a 90 expansion and upstart Uroborus made the system 96 stuff which was really a 94.1. Those two shops waged war right up until the big mess five years back with the EPA.

The bulk of the german color rods had a high enough lead content that the mismatch with the glasses in use was not an issue unless you diamond sawed the work piece. Then it blew up. The yellows and reds would never fit since they had no lead in them. They were mostly about an 84 expansion

Spruce Pine originally made the first pelletized ( sometimes) batch back I think as far as 82. The first formula had too much lithium in it and it ate liners alive ( It was a 93) so Nick dialed back and the '87 became the baby elephant in the room which would outgrow everything. Lots of people don't know that Spruce pine offers more than one pelletized batch. Since the numbers are supposed to mean something, 87 is an English and Turner Calc of the formula. If you measure it, assuming a start point of 19C ending at 300C, a 4.000 length of a rod should expand to 96. Appen does a better job, but Hey..

I'm no expert on the genesis of the 104's. It seems to me it was an Italian standard pushed by Effetre. Bright colors, really soft but lampworked only. The big American thrust was on furnace work.
I'd be happy to hear any additions to that set of recollections. I have gotten tired of typing so now I'm moving to severe editing which isn't good.
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Old 11-17-2020, 05:00 PM
Josh Bernbaum Josh Bernbaum is online now
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I didn't find the bit of work I did years ago with blowing bullseye to be that challenging to work with. I also, after about 3 days, got pretty used to the 103/104 LEC clear and colors they melted in Japan when I taught a class at Aya Glass Studio there. I'm most familiar with the feel of the 96's of course, but I think that melting so many of my own colors over the years has helped me to expect differences in workability and just try to adapt to those with each different melt as much as possible. And in that sense, workability is determined by more than just the resulting expansion number but also by what ingredients are in the mix. I try to make the colors I melt fit Spruce Pine that I use for my clear, but if I were mixing my own clear I don't know if I'd stick with the 96 LEC if I didn't have to. Just a couple of my thoughts on the matter. I'm also glad though to never have had the pleasure of trying to work with the John Mansville marbles. My guess is I'd have trouble getting used to that.
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Old 11-17-2020, 06:17 PM
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Believing in physics is such a great place to start.
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Old 11-17-2020, 09:36 PM
Nick Delmatto Nick Delmatto is offline
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Quote:
Originally Posted by Shawn Everette View Post
It's most likely a result of manufacturers creating a base glass for specific applications. 90 is a great fusing glass, but garbage to blow. 96, depending on source, can be a good for fusing or blowing, but rarely great for both. 104 was designed for lampworking when you still had to pump the bellows yourself. There are always exceptions, but that's probably it in a nutshell.
With 50 years now at this, I've gone through Fenton Cullet at Kent State, factory batch formulas, Spruce Pine batch, and now for the last 12 years - factory cullet with a COE 89 (lifetime supply), mixing my own colors plus some Bullseye. It sometimes takes more reheats to get things melted in, but it's not garbage. I'm used to it & know how to treat it & it's forgiving & durable. That's good enough for me.
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Old 11-18-2020, 11:53 AM
Shawn Everette Shawn Everette is offline
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I haven't had a ton of experience with it, but I found it to be short, yellow, and easily corded; all things that I don't look for in good glass. The 90 stuff from spruce might be better, but the cuttoffs from bullseye are probably not the answer for most studios. Not to mention, unless you're making your own color, the factory available stuff is not dense enough for most applications. People like Petrovic make amazing things with it, but I'd move to batch way before using that cullet again.
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Old 11-18-2020, 11:15 PM
Nick Delmatto Nick Delmatto is offline
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My 89-90 cullet is neither yellow or cordy. I make paperweights with it. So, to call all 90 cullet as garbage isn't correct. You had crappy stuff that happened to be 90 COE.
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Old 11-19-2020, 07:52 AM
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back with the original question:

The primary makers of high expansion glass have been considered to be Effetre and Lauscha. In both of the companies, color was the primary consideration and every time you add something to a glass, it changes the expansion. It is the case in both companies that they make a line of glass with some being incompatible with others. I've measured as much as 6 points difference in both companies. If the glasses are highly leaded , and many are, there is tolerance for mismatch as long as you don't break the surface tension and saw it. The same conditions exist for German color rods that cannot have cadmium in them since cadmium and lead produce vile colors. So, the bright reds and yellows need a very specific clear.

The thing about cullet from the past worth remembering is that no one got rid of it at Gabbert because they were in love with it.
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Old 11-19-2020, 07:56 AM
Shawn Everette Shawn Everette is offline
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Do you mind sharing your cullet source? Cause the only one I'm aware of is bullseye, and it's garbage.
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Old 11-19-2020, 08:05 AM
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Quote:
Originally Posted by Shawn Everette View Post
Do you mind sharing your cullet source? Cause the only one I'm aware of is bullseye, and it's garbage.
*****
We come full circle: I remember when keystone cullet at .02lb was fabulous. Then, the small group of glassblowers who used it told all their friends and it became terrible overnight. They were throwing anything clear in there. The belly dump truck in Mark's driveway was the killer.

When I was making big optical pieces and we were doping the hxtal for color, I always made a point of having certain pigments sitting out prominently when people visited. They didn't work. I kept the good ones off in a drawer. I never told anyone where the optical glass came from.

Mary Beth designed a sandblasting tool about the diameter of a pencil. Dan Fenton tried it and loved it but he pushed it into the market with another man. Soon when we went to order more parts from the original supplier, we were told that they wouldn't sell to us and to buy them from Fenton. I'll always remember that.

In teaching, you have to give up what you know. The private shops don't have those restrictions.
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Old 11-19-2020, 08:32 AM
Shawn Everette Shawn Everette is offline
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I call into question the usefulness of someone saying something is great when it's not available to anyone else. It's pretty obvious to most that I was referring to bullseye from the start, so not elaborating on what's actually better doesn't do us any good. Bullseye was designed for, and is great for fusing, especially now that qc has gone out the window on the flat 96.

There's a comparatively huge spectrum(no pun intended) of options on the "96" front, which is why I left room for variance. And yes Pete, we know, some of it is actually 94.
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Old 11-19-2020, 02:25 PM
Nick Delmatto Nick Delmatto is offline
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Quote:
Originally Posted by Shawn Everette View Post
Do you mind sharing your cullet source? Cause the only one I'm aware of is bullseye, and it's garbage.
Lancaster Glass (Ohio) melted this clear & sold it to folks who asked for it but they didn't look for customers. They also mixed the Spruce Pine batch for a few of us 600 lb at a time. It was a sweet deal that lasted about 35 years. When they went out of business in 2007 I bought my lifetime supply. The rest (about 100,000 lbs) went to a recycler. If I had a building to store it in I would have bought that also. So, it's no longer available.
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Old 11-19-2020, 03:33 PM
Shawn Everette Shawn Everette is offline
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While your situation sounds fairly appealing, it's not exactly available to anyone else, so you're glass is one of the exceptions referred to at the beginning. I won't recommend that any general studio use bullseye cuttoffs, if they like anything resembling good blowing glass. The only reason the place that I used it had it is because they got a ridiculous amount free when they started their hot shop. I haven't heard of anyone that actively uses the 90 from spruce, so I can't attest to its workability, but there is apparently enough a market for them to bother to make it.

Before my time, my old studio ransacked Lancaster Glass at the closing. I'm surprised they didn't go after the cullet, being the scavengers they were. Most of the users would have been die hard Reichenbach Zimm, and Kugler users, and they didn't have a color furnace; so that probably has a lot to do with it. They've probably still got a couple massive laps from there that never went into use, probably could be had for a song.
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Old 11-19-2020, 07:06 PM
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Jeez Shawn, I think one of the things about boards like this is being able to crow when you did something right.

Your reference to raiding Lancaster when it came apart seems to me to be typical of this sort of raid. When Fenton went under, I knew the auction was happening and didn't advertise it. I didn't participate either but I know people who did and they did well but they actually went to the site, looked at the product and bid. Some now admit they got too much and are trying to sell off the excess.

Buying surplus is not for the faint of heart. Maybe you know that sys 96 is really a 94 but it continues to surprise people, so I keep reminding people that it ain't what it seems.
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Old 11-19-2020, 08:34 PM
Nick Delmatto Nick Delmatto is offline
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Yes Pete, I have a few AZS channels from that Lancaster raid that I'll never get around to using. Furnaces are getting smaller as I age.
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Old 11-20-2020, 08:56 AM
Shawn Everette Shawn Everette is offline
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I acknowledged his fortunate circumstance, and good for Nick on taking the opportunity, but it simply reaffirms the original statement that the largest supply of 90 available is not great glass to blow with. If you're going the batch route anyway, I don't see why you'd choose 90, unless your predominate work was roll ups. Something about exceptions not making the rule?

They had the fortunate circumstance of occupying a mostly empty warehouse where people dumped what they thought might be "useful". I had the unfortunate task of scrapping 90% of it when we moved because it was just junk. Since I left there seems to be some reversal of course.
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Old 11-20-2020, 09:16 AM
Tom Fuhrman Tom Fuhrman is offline
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Back in the far past, people used all different types of cullet and adjusted it to meet their needs. Stephen Powell used cullet from a fluorescent tube manufacturing plant for many years in his own shop as well as at the school he was at. I still remember the many studios were using Louie cullet and then they changed their formula without notifying anyone and what a mess that was.
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Old 11-20-2020, 02:23 PM
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when you think of "cullet", it was droppings from process in a factory. Factories used no more than 15% cullet in their batch configurations. They were happy to get rid of the excess through Gabbert, a company that bought and sold different factory cullets. I have no idea what they did with the stuff prior to the toledo workshops.
When Nick Labino came with his daytank and bags f fiberglass marbles it hadn't yet become cullet. It was a raw material used to make fiber batting. I have no idea t this point as to how much of the Louis Cullet originated in blown ware. There certainly was a lot of cullet but I never sensed it to be a primary product at all.
Bullseye had a market in casting and slumping and did indeed feed their clients the 90 expansion drizzle since it was a serious part of the business model. The rest of the community migrated towards the pelletized batch Harvey was selling. It became the defacto standard even though Bullseye will argue to this day that 90 expansion is better than 96. My own thoughts were that a 93 might have been a better compromise. Dishwasher breakage is part of the 96 experience.
The first actual cullet made as a primary product was Spectrum cullet. Spruce Pine tried but due to a poorly designed furnace, the product never made it into the mainstream. Oceanside is making sys96 cullet right now. Cristalica is an irritating 97 expansion glass. Bomma is another. but is a 96.

But none of it was or is top quality glass. That takes time and care
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Old 11-20-2020, 02:58 PM
Shawn Everette Shawn Everette is offline
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I think "top quality" really all depends on what you are trying to do with it. By the time you start incorporating frit or powder, peak optical properties go to the wayside. Something relatively bubble free, cord free, color neutral, and with decent heat times fits the bill; which most of the modern primary cullets can do a alright job with. Most of the time.

The cuttoffs, 96 or 90, were never designed for blowing and it shows. Can you do it? Sure, but they are much farther down the quality curve than those that were actually made for off hand blowing. Not to mention the additional furnace wear from how much off gassing they do.

I can't say I've had dishwasher issues with any "96". Cats on the other hand...
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Old 11-20-2020, 07:13 PM
Nick Delmatto Nick Delmatto is offline
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A late friend of mine added a lot of flourspar & soda to his Lancaster cullet to get it around 93-96 to fit Kugler colors. That fluorspar really ate up his furnace. It looked like a meth addicts mouth after 2 years or so. I couldn't get him to change it.
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Old 11-21-2020, 07:22 AM
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My opinion is that until you've had the opportunity to actually use better glasses, that it's far easier to dismiss them.

Damascus is beautiful.
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Old 11-21-2020, 10:56 AM
Shawn Everette Shawn Everette is offline
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So you're telling me that if I use optically perfect glass I can double my pumpkin price on the blue hairs? Or triple the price for students that are already complaining when we're one of the cheaper outfits around?

I've used a lot of glasses, the spruce Gaffer batch probably being my favorite, but still had its flaws. Realistically you have to look at the situation you're in and decide what's practical. Agonizing over perfection in a public studio is a fools errand anyway.
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Old 11-21-2020, 12:59 PM
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A substantial amount of my interest is in the actual glass itself. Part is also in its use as an artform. So, we're very different. Craftweb doesn't really have a very dedicated group that has my interests.

Around 35 years ago, I was making these wedge shaped pieces and polished the front and the back of the wedge much more thoroughly than I had before. I began to use pumices that were graduated in their fineness. Where I had only used 0 3/4 initially and then go to cerium. I added a layer using FF and then one with FFFF which is really fine. I switched to Canetto Lipari pumices from Italy. I worked them a good deal longer. Then I used a very high quality cerium used in the photo mask divisions for motherboards (PMD's) . It is very aggressive but one has to cut through three layers of skin after the pumice work to reveal the true surface. The glass I was using already had a reasonably high refractive index but the polishing process began to reveal a "Bounce" in the finished piece wherein I could see reflections of one polished surface off of the other. It was almost like watching a print develop in a darkroom.

If Jon Kuhn's work was made in any ordinary glass, it would fall totally flat. F2 from Schott has such a profoundly high refractive index that if you put your driver's license on the end of a six foot thick section of it and looked through it, you'll see your drivers license as if it was in front of your nose. My work with Schott involved the index as well using the BK series in combination with the F series glasses. . A chalice for light as dad said.

As Mark Peiser observed, Sodium and calcium are really cheap terrible ways to make glass and that other fluxes and stabilizers made a far nicer product. That's where potassium or strontium come in. They will totally change your attempts to make color if you have any of those interests. I do. There's a ton of unexplored territory in glass composition. Phosphate glasses are the last great unexplored territory.

So, you do with it what interests you I suppose. Being on the back nine of life, I take those interests more immediately. I don't make pumpkins at all. I'll keep running this board and I will keep encouraging everyone to use this short time to do their best work.
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