GAS article on compatibility

[Steven Maslach]

I pulled canes of Reichenbach colors and sent them to John Croucher at Gaffer to be trident seal tested. Here are the results:

R61 no strain
R12 no strain
R157 +2.5
R75 +1
R124 +3
R158 +3
R186 +2
R83 +2
R3 - 3-4 points lower, test seal broke after 24 hours
R170 - 0.75
R229 -0.5
R77 -3

These colors range 91 to 97.5. The numbers reflect the stress within the trident seal. The same stress would be produced by soda lime glasses whose LEC's were off. My CT23a is found to be 94.5, and R3 acts like 91 and R158 produces stress as if it were 97.5. These tests were compared to my CT23a, mixed and pelletized by Philips. I had to stop using this batch, and lowered my clear 1.5 to be in usable range of R3, R12, R61 and R77, all of which I use a lot. That put me farther away from the rest of the Reichenbach colors, and any color bar commercially available.

I will post the article I've written on compatibility for GAS. (next post).

I would appreciate your response to this thread. Please tell me- What has your experience been with European color? What is your base glass? Does your process require a close fit? How do you test for fit? Thank you for any and all responses.

[Donovan Brooke]

Steven, great post! thanks.

I melt gaffer batch readied by spruce pine. I can tell you that I wish I would have seen a post like this before purchasing OX blood R125. Very not compatible.

Donovan

[Donovan Brooke]

P.S. Anyone know of a compatible replacement? (dark rust color).

Donovan

[Pete VanderLaan]

I have some sticks of a deep brick red that would fit fine Donovan. Beyond that, the issue is that any of these reds and yellows based in cadmium are going to be soda lime and not lead based, The reason is that the presence of lead makes this whole family of glasses turn shit brown. The soda lime family which makes these colors properly will not be in the expansion range of the commercial clear 96 glasses. This is usually true of German colors but is not true of Gaffer who makes the stuff in a more logical fashion.

In my humble opinion of course.

[Steven Maslach]

Compatibility Article for GAS

There are two types of testing for glass compatibility; technical testing, measuring of a glass using scientific procedures, and process testing, by which glassmakers test a glass for their use. In this article I will address the problems surrounding technical testing.

Different colored glasses require different base glasses. Lead glasses generally make the deepest and richest colors and are used for gold-bearing colors and dense white. Most glassmakers use a soda-lime as their base glass. These glasses are quite different in their viscosity, setting points and other physical properties. Therefore, glasses that measure the same expansion on a dilatometer may be incompatible. A dilatometer is a heated quartz tube within which the glass sample expands on heating. A dial indicator measures the expansion. This test asks the question "How much will a glass expand up to 300 C?" The soda-lime clear glasses that most glassmakers use is in the range 90-97 (x .0000001 cm/cm/C) by this test.

The use of numbers, representing expansion, in the advertising of color makers and sellers has led to the belief that glasses with the same number are compatible. This is often untrue.

Stress in clear glass is revealed under a polariscope. The trident seal test, developed by Henry Hagy at Corning, measures the final stress (which cannot be removed by annealing) between two glasses. A polarimeter, a polarized light measuring device, is used in this test. This test does not concern itself with expansion, viscosity or other properties of glass. It goes to the bottom line "How much stress is there?"

How compatible do glasses have to be? This is where process testing is required. Blowing color very thin, relative to surrounding clear glass, will tolerate stress well. The forces generated by the relativily small amount of color cannot overcome the tensile strength of the clear glass. If someone saws or uses a crack off in their process, or makes work where dense color is fused directly to color, a closer fit is needed. Bear in mind that if there is final stress in a glass object, it remains whether a piece is made thin or not. Glasses under stress sometimes break years later, often brought about by temperature change or other cause.

Common process tests include: 1) ring tests, thick and sawed, or thin and cracked off, 2) chip tests, 3) color casing in clear, then grinding or sawing through to color, 4) polariscope examination, and 5) thread or pull tests. Of these tests, the thread test is the least reliable. None of these tests are meant to be technical, verifiable tests, but are important to each glass maker to test for his or her use.

The trident seal test is considered by many to be the best technical and process test. Glassmakers who use color that is made using trident testing have fewer problems with compatibliity. The trident seal test is made of three rods, two color or clear rods fused at both ends to a center glass rod. The rods must be uniformly made 2-3 mm. in diameter and about 50mm long. * The test requires some skill in pulling uniform canes from color bar and takes about 25 minutes per test, annealing and color bar warm up time not included. Pulling canes from molten glass takes less time. The results can be duplicated and made in any glass lab or studio. The amount of stresss is measured on a polarimeter. The test seal can be sent for examination to another location, for example, a glass color factory.

I have written an open letter to color makers, sellers and glassmakers to address the fact that some glasses are not useable within their advertised range. I had 12 colors from one color company trident seal tested for this article and they show stress equal to a 6-7 point range, 91-97.5. These are the results of translating stress measuremnents into expansion numbers to relate the level of incompatibility. My CT23a glass was found to be 94.5. These colors are unusable for anyone who requires a close fit. It is not possible to make one soda-lime glass compatible with each of these colors.

I feel color and batches should be technically tested by the trident seal method to provide a real description of what glassmakers buy. I am asking that color sellers purchase polarimeters that are available for their customers use. Olympic Color Rod has agreed to do so. Colors of higher expansion already reference popular base glasses, and I propose that the lower expansion glasses be trident seal tested to a reference glass, such as Bullseye or a Schott glass.

In conclusion, wide use of this improved test will lessen compatibility problems and misunderstandings throughout the glass community.

* "The Trident Seal- A Rapid and Accurate Expansion Differential Test" Hagy, H. E. Journal of the American Ceramic Society Vol. 62, No.1-2, pp 60-62. 1979

[Donovan Brooke]

thanks Pete, so you are saying your brick red may have the same issue?

Btw, I had a chance to see some of your... ah hum, I'll get the name wrong I'm sure... deep scarlet red. Very nice color. I may be interested in that color as well if I can scrounge up some pocket change. If Scott is watching, he should be able to correct me on the name of that color.

Donovan

[Steven Maslach]

The following is the last paragraph of my article-

I have posted the open letter on Craftweb at http://talk.craftweb.com, along with an expanded version of this article, detailing the test procedures. There is information on this subject at www.bullseyeglass.com and http://www.gafferglass.com/. E-mail me for more information.

Steven Maslach smaslach@earthlink.net

[Pete VanderLaan]

Steve I think that looks great. GAS is lucky to have you writing for them. The only change I would make is in the dilatometry section where you don't mention the starting temperature, which I believe is 19C. If there is no starting reference and I don't think there is in the ASTM standard, then the final result is meaningless. As near as I can tell, 19C seems to be the temperature at which lab technicians are comfortable in white coats.

When I started doing that testing up at Los Alamos Labs, they wanted to put the samples in an ice batch and start as close to 0 C as possible. That gave really inaccurate readings against known value glasses. Once I took it up to 19C ( about 68F) everything worked great.

Donovan, the glass fits sp87 just fine. It fits gaffer batch just fine and any of the phillips 96 glasses I am aware of. I would not use it with Seattle batch products since my opinions of the products are such that you might have unfortunate results unexpectedly, from time to time, when you least expect it or desire it, again in my opinion of course...

[Pete VanderLaan]

Originally posted by Donovan Brooke
t. deep scarlet red. Very nice color. I may be interested in that color as well if I can scrounge up some pocket change. If Scott is watching, he should be able to correct me on the name of that color.

Donovan

I make several reds. I make a copper ruby which I think is the best on the market and is available from Spruce Pine Batch Co. I also make an even better cad sel red but I don't sell it since it is not really a glass happily made into rods . I actually make some nice Gold rubies as well but they aren't on the market either. You do learn how to make them all in the color class, which I will be posting times and participants for quite shortly.

[Scott Dunahee]

You're talking about Pete's Copper Ruby, Donovan. Use it sparingly as bar and NO REDUCTION. NO REDUCTION until it's cased. Did I say NO REDUCTION?

BSD

Did I mention you only need a little bit? Like WAY WAY WAY less than a Cad Sel red? Oh yeah, and it strikes. Very cool stuff. You'll see what I mean about the strike.

[Steve Stadelman]

I did a bunch of bowles with silver green and blue powders over R61 powder and then drizzled Pete's copper ruby over the color layers. I melted a little in a coffee cup in the glory and used it all in each session.

Totally cool results.

[Steven Maslach]

Can we go back to the point of this thread? There is a rot at the center of the color and batch business, and a reliable test that can influence the makers and sellers of color. Change would be beneficial to many glassmakers.

Again, can you tell me of problems you have had with European color, what clear you use, and how you test?

[Pete VanderLaan]

Now Steve don't let your shorts get all in a bunch. These guys are known for wandering.

literally any of the soda lime cadmium selenium based rod in either transparant or opaque from Kugler. You know how I test.

The bulk of the leaded kugler opaques do not fit SP87 or any "96" rated clear as is graphically demonstrated anytime you try to make a paperweight with them.

[Drew Fritts]

Steven,

I don't mean this to sound snobbish or indifferent, and I’m not trying to piss you off, I really am curious… What am I missing? I’ve read all your posts and your article and I’m still struck with the same question, so I’m sure I’m missing something. The question is this, “Why keep beating your head against the wall by battling companies that obviously don’t care what you think?” Gaffer has addressed the issues you raise. They say their clear and their colors are completely compatible. If that’s not true, I’d sure like to know before I go and place a big order in the next week or so. Also, Pete’s Flying Colors are supposed to be compatible with Gaffer as well, are they not? I don’t see why you don’t just buy from the guys who are trying very hard to do exactly what you’re asking? Wouldn’t it be easier to buy clear and color from guys who are committed to being compatible than trying to fight everyone else? And, if everyone would buy from them, and stop buying from the companies in question, wouldn’t the problem work itself out anyway? I realize that you’ve been using your own clear for quite some time, but really, is it that good? Is it so much better than Gaffer’s clear?

Again, I’m sorry that I’ve missed something, but I really would like to understand. Now I’ll take off my rose-colored glasses and sit back and listen…

Drew <+><

[Steven Maslach]

This is to answer Drew-

In my experience, the colors R61, R11, 12, 13, R3 and a few others cannot be improved on. In the specific use I have, the color is made into cane, picked up and pulled again, annealed, re-heated, twisted, shaped, annealed, re-heated and torched, and annealed again. Few colors can hold up to this, and are dense enough. The Reichenbach colors are amazing. It has also taken years to develop the tricks to make it all work, to learn the colors.

If I were primarily blowing, I might use Gaffer clear and colors. But I work in thick glass, and low expansion and zinc-free glasses are better. Zinc looks cordy in thick sections, for example, looking across the crown of a paperweight. I don't know how much zinc is in Gaffer and when I test melted it, it didn't test well. For the castings I do, yes, my glass is better.

When I buy neodymium or erbium or other chemicals, I receive a analysis that is the proof of purity. It tells me what I am buying. This is how color and batch should be. We need to know if the color fits or not, without a lot of testing. We should also be confident that the color doesn't drastically change from melt to melt. But if it does, we need a test that can tell us what is wrong- the color or the clear. We need a test the color makers and sellers trust.

Finally, I have had people tell me that I won't change anything. That may be true, and I may have to switch to Gaffer colors. But I believe that if people start using the trident test, the European color makers will have to adjust. Tweaking their colors is really not that big a deal.

There, I've barfed it all out.

[Pete VanderLaan]

I think from a market pressure standpoint it would be helpful to know where their customers are. I have always thought the junk was sent to the USA because no one really wanted to return stuff 8000 miles away. I started making my own color because I could control it.

But then, if you are a tiny niche in a niche market compared to Europe which I don't actually think is true, you are not really worth bothering with economically. The bulk of sales go top people who blow and get away with murder. I mean, I stopped retailing color when I got a call at 6:00 AM from a guy who wanted a 1/2 kg stick of color fed-exed to him because "he had a project".. Good Luck.

[Steven Maslach]

The US is a big market for all color makers. If test results clearly show their color is off, they will probably respond by improving their fit. This is good for everyone, makers, sellers and users. The important point is that we, the end users, have to start using trident seals. And why not? They are no more time consuming than ring tests, and can be verified. If we use them and trust them, like Gaffer does, the sellers will not be able to ignore bad glass or screw-ups.

The cullet seller whose supply changed- I didn't respond to this before. I think a glassmaker could make test cane of their glass when the glass is working right. When they get a new shipment, they can trident seal the new glass against the "right" glass. A 25 minute test could save a lot of trouble.

[Pete VanderLaan]

Well, two things: My big problem with the trident seal is the damn cost of the polarimeter at over two grand. That's why I ring test.

...and two: cullet suppliers. Josh Simpson has been having troubles yet again and it's insideous. Random barrels out of 30,000 lbs of cullet don't fit. He can make 150 grands worth of weights and they all break- randomly. I was there at the end of August and it was all going on and then it stopped and then it started again. I did go thru test procedures with him but testing cullet scrap is a genuine PIA. I am going back again next week. I would return the entire load of crap but that doesn't seem to be on the table.

But I do agree that the color folks could standardize. It would not be hard. I just don't think they will. Nonetheless when you get people who in my humble opinion bring in questionable cullet and market it like it's an isotoner glove the problems will simply develop in new ways.

[Steven Maslach]

hey- I just addressed that in my last post. Test the new cullet shipment against your "standard" cullet cane. You can't test any easier- pulling canes from molten glass is so easy.

Don't buy the damn polarimeter. Support the concept of the sellers buying them. Send your seals to be read.

[Pete VanderLaan]

You are right. Pulling cane from molten glass IS easy. Pulling it from chunks in a cullet barrel is however a PIA. The current choice for Josh is to melt a tankful and then test, or test a chunk from a barrel, OR actually trust the cullet salesperson to actually sell you a consistent product in the first place thereby rendering this process unnecessary.

I also mistrust the fox guarding the chicken coop in terms of having the color salespeople testing for me since I have these opinions about some of the ethics of the salespeople. But it's just my opinion.

[Dave Bross]

Yeah, and then there is the magic barrel where the problem begins half way down and you just tested a piece off the top. I'm guessing we're discussing a W. Virginia cullet, which has some very cool glasses but the expansion/viscosity can be very different from batch to batch and needs much checking.

Spectrum is probably the closest to doing something good in the cullet arena. There are some problems but fit hasn't been one of them so far. Now if they would just finish fining the glass before they send it out..........

Not happening from the looks of their tech info. I suppose they have their reasons????

http://www.glasscolor.com/batch/batch_vs_cullet.aspx

see section "e" as pertains to melting at 2100. Although, it is the only glass I've seen that will actually get rid of all those tiny bubs by sitting a few days. Low viscosity I suppose, which would also explain the good glass overnight if cooked at 2200. The strain temp. on it is 890 too.....how did they do that and still have it as soft as it is and an anneal temp. of 950? I'm guessing fluorine or some other halogen.

[Pete VanderLaan]

so far, we do not seem to have an issue of mixed glasses in the same barrel. When we get to that, it's time to throw out the whole 30,000 lbs. I also don't know who the supplier is ( really!). The really hard issue is that when it's good, it's the best cullet I've ever seen and when it's bad...well....

It is the total risk of cullet. But to give a better overview I would say that I am more than capable of making mistakes in the mixing room and I probably do it more frequently than any one else does. It's why I use two scales. Even then, humidity in the batch chemicals can play hell on the process. I used to buy stuff in large quantities but humidity began to cause problems. I can't yet imagine how to handle it in New Hampshire, short of dehumidifying the storage area.

If I knew who supplied it, I would say. Josh seems pretty sanguine about it. I am not afraid of naming names. From here on in, when I name names I will also say "it's my opinion that".

In my opinion, The fact that Seattle batch tried to silence our opinions with an attorney should simply be noted by the purchasing community and they should follow their own consciences.

[Steven Maslach]

Cullet- I just haven't ever used it, and can see the huge problem when you get shipped wierd stuff. Would a thread test work here? It might be that a quick and dirty thread test would show a glass change without much effort. I remember Jim Lundberg had a set of liquids that indicated density. The glass sample would sink in one, and hover in the same density. Jim swore by the density test to show batch errors. He got them from an old glass factory, I think. It is mentioned in The Handbook of Glass Manufacture, by Fay Tooley. ( I think)

After reading the Lani LEC thread I thought there might be replies on compatibility and European color from the Pioneers. Hey Henry, or Durk or others- are you out there? Why has everyone put up with color that is so far off, for so long?

[Phill Cusens]

" Josh Simpson has been having troubles yet again and it's insideous. Random barrels out of 30,000 lbs of cullet don't fit. He can make 150 grands worth of weights and they all break- randomly"
I reckon if this is happening then it is Josh's own fault, throw away 150 grand and not spend 2 grand on a polarimeter!!! Penny wise pound foolish, every glass blower who produces a reasonable amount of work should own one!!!
Still the easiest and most accurate test around!

[David Paterson]

"Why has everyone put up with color that is so far off, for so long?"


Perhaps the problem is that these issues only show up in thick castings, or other thick pieces. I have been blowing glass for 20 years, and have only very rarely seen a piece crack. The same is true for any other blowers that I know personally.

In a year, out of thousands of pieces, perhaps one or two might crack with a mixture of colors swirled together. And perhaps nothing at all that year.

Most of my work is thinly blown, however, I do make paperweights up to about 3" thick.

For over 10 years, I used FHC cullet, and Kugler, Reichenbach, and Wiesenthal. I stayed away from bright Kugler reds oranges yellows.

If there is no perception that something is broken, there will be no call to fix it.

I also question if the problems you are having are at least partially related to annealing, cooling rates above and below the strain point, or other technical issues that only affect large castings.

For example, if you anneal and cool a casting that is 4" thick, and 24" x 48" in other dimensions, do you anneal and cool for a 4" piece, a 24" piece, or a 48" piece?

When you start pushing the limits of any technology, sometimes problems show up that are virtually never seen in the mainstream.

In Josh Simpson's situation, there is absolutely no quality control over cullet, unless it is a manufactured cullet like the Spectrum Nuggets. You are literally using someone's garbage, and the issue really doesn't belong in a discussion over the issues you have raised. You may be getting barrels of glass that ended up as cullet because of a batch error.

I used to get my cullet from Gabbert. Over the years, I have seen them occassionally ship "wrong" colors, "new" FHC supposedly right out of the furnace that is full of bubbles and looks cordy, etc etc. I am not sure how much, if any, is Gabberts fault. They are selling someone's scrap.

While I think what you are trying to do is admirable, I also think that you need to come up with a way to convince the color makers that the vast majority of their customers want this issue resolved.

[Pete VanderLaan]

Originally posted by Steven Maslach
Cullet- I just haven't ever used it, and can see the huge problem when you get shipped wierd stuff. Would a thread test work here?

***************
Mixed stuff is the worst. I think it would help to pull cane and we are going to look at doing samples from all the barrels when I go back there thursday. He also makes and keeps tons of old cane which makes it even harder.
I also think he will buy the polarimeter.
*****************

I think. It is mentioned in The Handbook of Glass Manufacture, by Fay Tooley. ( I think)
***************
I will look in Tooley which I have never taken seriously. Thanks!
***************

After reading the Lani LEC thread I thought there might be replies on compatibility and European color from the Pioneers. Hey Henry, or Durk or others- are you out there? Why has everyone put up with color that is so far off, for so long?

************

Most people blow with color, not make solids. It doesn't affect them the same way. They simply don't saw or grind their work if it has color in it. It's kind of an out of sight out of mind thing. I used to hear at Pilchuck "You can put the purple over the yellow but not the yellow over the purple." It's systemic and accepted to be stupid and anti technical. Very sad.

[Steven Maslach]

Originally posted by David Paterson


Perhaps the problem is that these issues only show up in thick castings, or other thick pieces.


Arrgh David- I said in the last thread that I do not have problems with my thick castings, and I posted a picture of 1" marbles that have shattered. I only started this because of the extremely bad fit, breaking small, strong simple pieces of glass. Before this happened, I was happily unaware of how bad certain color was. I wanted to address the problem for myself and for everyone that needs a lower expansion glass than Gaffer. I have asked the members here to tell me of problems with glass fit and I only have a few responses, but I am sure there are many that are as unaware as I was. I assumed that when I did have problems, the clear may have been off. After Philips made my glass, I was confident that the clear was consistent.

[Donovan Brooke]

Steven, I think getting the manufacturers to "change" is the wrong approach. I just think thats like try to get an elephant to stand when it don't want to stand. I like the idea of a place (probably on the internet) where we (as color buyers) can go to check a database to make sure the color we are interested in is going to fit our clear before we purchase it.

I can build a web database app if I thought there would be folks who would help populate it (with factual data).

Donovan

[Drew Fritts]

I found the information Steven posted at the beginning of this thread (specific COE of specific colors) very useful and would LOVE to have a chart that shows that info for all the colors. However, can we assume that each batch of the same color by the same color manufacturer is reasonably consistent in COE?

Drew <+><

[Donovan Brooke]

Originally posted by Drew Fritts
I found the information Steven posted at the beginning of this thread (specific COE of specific colors) very useful and would LOVE to have a chart that shows that info for all the colors. However, can we assume that each batch of the same color by the same color manufacturer is reasonably consistent in COE?

Drew <+><


Drew, thats a good point. I think this could be worked in with the table possibly... either in the form of "comments", or in the form of allowing multiple "reviews" of a color?? I sure wouldn't want it to get too complicated but those are some thoughts. Ultimately, if the colors are not made consistantly, it would be a wasted effort to try and gather info. My guess would be that they would have to be fairly consistant however.

Donovan

[Pete VanderLaan]

my reason for mentioning the cullet issue, which David demonstrating his ADD again ,promptly dissed is that if your clear is going to wander from shipment to shipment there is a serious problem. The suppliers of clear scrap, or whatever cute name you want to give it need to be part of this testing process as well and that was my point. Currently, there is a major supplier in Seattle that supplies a clear glass which wanders substantially from shipment to shipment whenever I have tested it which of course isn't really testing, it's my opinion, right?

If the database can be developed showing the Hagy Seal results for any glass on the market, I will make a permanent location for the results on the board.

[Dave Bross]

The database would be nice but it would probably need info on particular batch numbers and maybe a provision for posting early warnings of a particular suspected bad batch.

Obviously, from what Steven is experiencing there are drastic changes in the same color from batch to batch. When 30-40% lead won't cover the mismatch in something as tough as a marble there are some big changes going on.

I think info on the clears is just as, or maybe more important. Spectrum, Gaffer, Bullseye and the Moretti clear (only the clear) are the only ones I see coming in on the money every time so far. Even in your personal testing you are lost without a good baseline clear to test against.

The batch number info would bring it to the immediate attention of the retail sellers if no one would touch a particular run of color that was way off something would have to give somewhere..

[Pete VanderLaan]

[QUOTE]Originally posted by Dave Bross
[B]

Obviously, from what Steven is experiencing there are drastic changes in the same color from batch to batch.

****************

I don't necessarily see that at all. I think Steven is saying that the colors are consistent and don't fit. I do think he is experiencing the notion that A fits B, and B fits C but does not lead one to conclude that A fits C.

[Dave Bross]

OK, I was thinking he had used them in the past with success and things had changed.

[Steven Maslach]

Here is the situation: I wanted to have my batch pelletized by Philips. I did lots of tests first. It is CT23a, and is in the middle of the colors I use a lot of, matching R-61. I probably had bad bar, R-12, and did trident seals to figure out the problem ( R-12 was 2.25 lower than R-61). I changed my formula down 1.6 to get closer to the low end colors I use, Cd-Se, gold ruby, etc. Everything was fine, until I tried new colors to re-design. Colors like R-158, a simple opaque. My current glass is about 4.5 away from R-158, and many colors are also too far off. It is not possible to make a clear compatible with all the R colors (or K colors, or any but Gaffer). I thought I should pass this along, and hold color makers and sellers responsible for their product.

[Steven Maslach]

This is new to me- I haven't spent a lot of time on a message board before. It seems that this form of communicating has some drawbacks- disconnects- people miss intended meanings, or don't read what has gone on before. Replies are out of sequence. I have seen sarcasm missed, and false assumptions made. It is different from speaking face to face, where we keep adjusting or restating things that are not quite taken as meant.

At the core, we humans are self-absorbed little monkeys. We all think that the experience we have is the experience everone has had. There is a continous under tone of exasperation, based in the idea that "the glass experience" for one person is the same as for someone else. We are often unable to see beyond ourselves.

I am in an unusual situation. After so many years in glass, and having made the colors and made them fit, I understand how screwed up the current situation is, both with color and the several clear glasses out there. Yes, I have been bitten by this problem. I want things better for me, and better for everyone.

I will give the European color makers the benefit of the doubt. I believe they think that if their colors read the same on a dilatometer, then it will all fit a single base glass. The trident test, measuring stress not LEC, is a revolutionary test. Gaffer has proved it is indispensible as a technical test.

If we glassmakers use this test, and insist on the dealers testing the colors they sell, the color makers will adjust their glass. It is good for business.

Although it was very interesting, the Lani LEC thread came to no conclusion, no result. Dozens of hours were spent. If I read Durk Valkema properly, Leerdam would sometimes adjust their batch to fit a Kugler color. Insane. It appears that Kugler and other colormakers have been diefied. Many people assume that the color is always right, since ir has been around so long. Also, many people that don't have a problem with fit don't believe there is one. Few people realize how this problem is not that hard to fix.

I am a "whistle-blower". To some this means "complainer". Many replies to my posts have assumed I was doing something wrong, or was on some wierd Quest of some type.

All I'm trying to do is to get the trident seal accepted, and asking the dealers and color/batch/cullet makers to get real.

[Pete VanderLaan]

well, it reminds me a lot of sheet glass for window people. Look at the annealing and how terrible it is. They could anneal it well but they don't by and large because they have a very captive audience and don't have to. Money will talk but it also takes an educated buying public making demands or taking their money elsewhere.

And you are right. The boards are a lot like panning for gold. Sometimes it really yields and sometimes you get nothing for your efforts.

[Steven Maslach]

I had to cut some process testing info from the GAS article, and would like to put it out here.

The chip test- there is a description of this test, used by warm glassmakers, in "Glass Casting and Moldmaking" Glass Fusing Book Three by Boyce Lundstrom. Bullseye also may have the information available. A 1/2" square of glass (1 or more) is fused to a sheet of known glass, and viewed on a polariscope after annealing. By bending the sheet, you can determine the type of stress. That is, you can tell which glass is more expansive. I have done this test on a punty, with one sample being tested. It is difficult to make the glass thin enough on a marver so it can later be bent. The stress halo is clearly visible, even if there are many chill marks.

The ring test- there are some variations of this test. The test involves the opening or closing of a vertical crack in a cased section of a cylinder. Color from bar is picked up first, then cased in the second glass. The test must be thin in order for the crack to open, or to overlap. The test requires the "feel" of the glass to determine the relative force needed to close, or open, the crack. A thin (lightbulb) test will open or close easily, but may need little force to return the crack to "normal". A thick test will only open a little, and may need a lot of force to close the crack. In a thick test, the crack cannot overlap. It is easier to test molten glass as you can easily reverse the glasses to make an open crack. I used this test for years to check on flourine opals, which change even when they are at working temp. It was not necessary to anneal the thin sample to get an accurate read on the glasses.

Peter saws his thick ring tests, and this usually, along with examining the crack, is a do or die test. A skilled glassblower like Ed Skeels carefully makes a cylinder with uniform and consistent thicknesses of each glass, anneals in the glory hole, and measures the crack to determine if the glasses are close enough.

A one piece wood mold is best for these tests, 3" d. or so. The mold should be barely wet if doing the super-thin test, the glass can be blown while turning, or not.

Casing a color and grinding into the color is a good test, and a sample like this can also be sawed or viewed on a polariscope.

[Pete VanderLaan]

I moved this thread from the archives since I found it to be really a pertinent subject and thought people would like to revisit it. I have no idea what Steve Maslach is up to these days but I think I will give him a call. I don't think things have changed much in four years,

[Scott Garrelts]

i bet LOTS of mistakes are made in every batch room. Its the holiest of most holy responsibilities to check yourself if you are mixing that batch.

if i mess up and am unable to fix it, i throw that batch away.

i bet there are mixers who wouldnt care, and sell that batch. pretty lame if you ask me.

[Pete VanderLaan]

I don't agree with that assessment at all. I used to have a deal where I did analytic testing for Spruce Pine when people complained about the batch. The deal was simple. I tested for linear expansion, viscosity and annealing point. If Spruce Pine made the mistake, they paid for the testing. If it was not a spruce Pine error, the client paid for it. On only one occasion did I find the error to be generated at Spruce Pine over a number of years. I think that mixing requires concentration and I am continually amazed that as few mistakes are made as exist. I make way more mistakes than Tom's crew ever has. They are always caught because I test every melt.

I did see radical differences in Seattle Batch CBG junk from test melt to test melt and therin lies the error in relying on chinese cullet.

[Scott Novota]

That CBG sure was cheap.

If you don't count the times pieces checked, cracked, or the amount of damage it did to the refactory on the furnace.


Scott.
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[David Patchen]

I really miss the too-frequent cords, stones, seeds and cigarette butts. Actually, I sometimes do miss the shorter working time, but not enough to even dream of putting up with the shortcomings.

[Pete VanderLaan]

don't get maudlin on me guys.

[Scott Novota]

Man, I had to look that word up.



Scott.
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[Pete VanderLaan]

As Anthony Quinn said: " I am a river to my people."

[Sandy Dukeshire]

Man, I had to look that word up.



Scott.
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can you pronounce it??