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View Full Version : Cristalica, SPectrum, blah blah blah


Pete VanderLaan
08-28-2017, 03:01 PM
I pulled the initial thread on this which essentially announced that Olympic is going to be carrying Cristalica. The question was, and is, what is the story then on Spectrum.
The last question was a request comparing the many cullets out there today which was off track but I'm OK with it.
It seems I may know more than what should be common street knowledge on this so I'll just sit back.
I do think that you will see serious significant price increases on cullet in general anywhere it's being made in the next six months. Think $1.75 lb or so, before shipping. Harvey was right when he said it can be a secondary product but not a primary product. It starts to make SP87 batch look really good but it's a killer for weekend wire melting warriors. I'll keep making my own. Enjoy the kool aide to come.

Scott Novota
08-28-2017, 04:37 PM
I use the C-cullet for ease of use but I could switch over to batch pretty quickly and with a moly not suffer any ill effects. I have started to notice and uptick in the corrosiveness. I am however burning though quite a bit more of the C-Cullet now. About 400lbs a week.

I will have to very quickly sit back and figure out which way I am going to jump. I really enjoyed making three new batches of color the last couple of months I might just invest a little to upgrade that process and get source material. IE> silica seems to be my hiccup right now of all things. I bet I just have not found the right supplier.

Anyway, SP-Batch will do until I make the turn.

Richard Huntrods
08-28-2017, 04:49 PM
... It starts to make SP87 batch look really good but it's a killer for weekend wire melting warriors. I'll keep making my own. Enjoy the kool aide to come.

Why? SP87 batch is great in wire melters as long as you don't overthink things and get silly. I mean, 8hr cook times? Seriously?

(I do seem to recall someone once mentioning that number for their cook times at 2250F, but I could be wrong as I'm getting old).

Mind you, given the way folks overthink cullet (again with the 2250?), SP87 is really no more difficult. The bonus is that it's pretty easy on pots and refractories, is the "elephant in the room" for handling and such, and is a really good deal.

I also have to say that I do love your glass formulation. It was just as easy to cook, and produced a glass that was just as easy to use and work, but the big benefit was a final glass that was much more brilliant in the finished work. Thank you again for letting me test it.

Eben Horton
08-28-2017, 05:07 PM
Why? SP87 batch is great in wire melters as long as you don't overthink things and get silly. I mean, 8hr cook times? Seriously?

(I do seem to recall someone once mentioning that number for their cook times at 2250F, but I could be wrong as I'm getting old).

Mind you, given the way folks overthink cullet (again with the 2250?), SP87 is really no more difficult. The bonus is that it's pretty easy on pots and refractories, is the "elephant in the room" for handling and such, and is a really good deal.

I also have to say that I do love your glass formulation. It was just as easy to cook, and produced a glass that was just as easy to use and work, but the big benefit was a final glass that was much more brilliant in the finished work. Thank you again for letting me test it.
That was me with the 2250 cook. I used to charge on a Friday and let it sit all weekend and had perfect glass on Monday. Now I am busier and need to blow the day after I charge, so I cook at 2300 and fine at 2325 for 2 hours & squeeze at 1900.

I never drank the Cullet koolade... batch works just fine for me.

Pete VanderLaan
08-28-2017, 07:51 PM
I use the C-cullet for ease of use but I could switch over to batch pretty quickly and with a moly not suffer any ill effects. I have started to notice and uptick in the corrosiveness. I am however burning though quite a bit more of the C-Cullet now. About 400lbs a week.

I will have to very quickly sit back and figure out which way I am going to jump. I really enjoyed making three new batches of color the last couple of months I might just invest a little to upgrade that process and get source material. IE> silica seems to be my hiccup right now of all things. I bet I just have not found the right supplier.

Anyway, SP-Batch will do until I make the turn.
*******
Short Mt. Google them. It;s just great shit. Iron free, easy stuff.

Pete VanderLaan
08-28-2017, 07:55 PM
Responding to Eben.
I agree and actually go back 20 years from the creation of Spruce Pine. I view current glassblowers as profoundly lazy with little will to seek out necessary solutions to the ways to make glass. I suspect the economy coming will sort out a little of that. My renaissance friends think my vision is unlikely. SHow me I'm wrong.

$1.75 a lb? I think it may be low, but it's coming to you soon.

Pete VanderLaan
08-28-2017, 07:58 PM
I also have to say that I do love your glass formulation. It was just as easy to cook, and produced a glass that was just as easy to use and work, but the big benefit was a final glass that was much more brilliant in the finished work. Thank you again for letting me test it.
*****
Best glass I ever formulated. Thanks to John Croucher and Mark Peiser for being sounding boards during those months. . East Bay has said they will make it.

Art Freas
08-28-2017, 08:43 PM
Late in the day so excuse any math errors.

IF I pay 1.75 per pound for cullet, I get pretty much a pound of glass. IF I get about .8 pounds of glass with batch I need 1.25 pounds of batch to get a pound of glass. That means if I pay more than 1.4 per pound for batch cullet is more affordable, less than 1.4, batch is more affordable. I will be interesting to see the relative prices for cullet vs. batch going forward.

Josh Bernbaum
08-29-2017, 08:42 AM
That was me with the 2250 cook. I used to charge on a Friday and let it sit all weekend and had perfect glass on Monday. Now I am busier and need to blow the day after I charge, so I cook at 2300 and fine at 2325 for 2 hours & squeeze at 1900.


Have you noticed a difference in fuel consumption between the two methods?

Eben Horton
08-29-2017, 09:07 AM
Have you noticed a difference in fuel consumption between the two methods?

Its hard to say because I switched over to natural gas a few years ago, but I would think I did.

What I do now is crash it to 1700 at the end of the day and have it come up to working temp in the morning when i light the glory hole and annealers... Having my furnace running off of a GB5 was the best thing I ever did aside from the gas line... so easy to change the programs on it.

Pete VanderLaan
08-29-2017, 09:35 AM
Late in the day so excuse any math errors.

IF I pay 1.75 per pound for cullet, I get pretty much a pound of glass. IF I get about .8 pounds of glass with batch I need 1.25 pounds of batch to get a pound of glass. That means if I pay more than 1.4 per pound for batch cullet is more affordable, less than 1.4, batch is more affordable. I will be interesting to see the relative prices for cullet vs. batch going forward.
*******
I simply don't see the price increasing all that much on batch. I do see it in cullet. The Germans are subsidized and that can't last. I have trouble believing Spectrum has a realistic future. I don't think Olympic would want Cristalica
because they want to offer clients a choice.

Dan Vanantwerp
08-29-2017, 02:43 PM
Batch is starting to sound more and more appealing. I look forward to a thread announcement that the East Bay "Vanderlaan" batch is ready for order. Rather than starting with SP87, I think I'll await this version to make the switch. I am loving my chalcedony and look forward to seeing the results with a base glass Pete said would match it very well.

Thanks to Richard for mentioning his positive experience with it as well. I believe our furnace designs are from a similar vein.

I just expanded my own furnace to include two 17 lb color pots. Wow...I could start making some pure opal colors in addition to my cullet based formulas. I wouldn't even be thinking of this if it were not for this forum.

Pete VanderLaan
08-29-2017, 03:38 PM
Richard has certainly attested to the ease of melting my goop in a wire melter. Jim doesn't pelletize and that makes the melt even easier. It's still not a production item but he'll mix it.
To do a fluorine opal base, it needs a different formulation to match but I have it. I have not discussed mixing that with jim. It would be most unhappy in a wire melter, or rather the melter would be unhappy with it. Fluorine dictates a gas unit or a monkey pot which is a bit involved. Right now, there's no demand for either.

Dan Vanantwerp
08-29-2017, 04:48 PM
Ahh yes...sounded too simple when I wrote it down. The color base and fluorine...still, it might be less impact-full to the elements in my small color pots. I guess I will have to give it a try sometime to really find out. Gases do like to rise (especially hot ones) and I would hope they continue to do so right up and out of my crucibles.

The recent upgrades to my furnace included a 2" thick or so kastolite-30 "gasket" that forms a collar around the crucibles. Looks like an outline of Mickey Mouse: two small crucible holes and one large one. It doesn't seal the crucible contents from the inner element volume, but does a fair job to discourage transfer at least. Mark's original design used 1" fiberboard but I found it did not hold up very well.

My bad if it goes awry. Then, let the four worst words when used in combination be spoken "I told you so". :D

Richard Huntrods
08-29-2017, 05:39 PM
...It doesn't seal the crucible contents from the inner element volume, but does a fair job to discourage transfer at least. Mark's original design used 1" fiberboard but I found it did not hold up very well.
:D

I used cement to coat the lip around the crucible, going back about 1in all around. I'm still on my original fibreboard.

I also coated the bricks in both lids, and that's kept them in pretty decent shape. With cement coating, minor drips don't bore holes in the K23.

Using K23 in these furnaces is the trade-off of durability vs. insulation. There's no free lunch, but coating the bricks does help. I'm on my second maintenance lid (only replaced a few bricks) and my third gathering port lid.

I also cut back the opening in the maintenance lid (the big one with the gathering hole) and created a 45deg gathering port using rammable. The bonus about using rammable is that it's as close to impervious to molten glass damage as anything you might use. Mine is 10 years and going strong. I just can't do that total vertical gather thing.

Pete VanderLaan
08-29-2017, 06:36 PM
.
There's no free lunch,

[/QUOTE]

****
I've heard that somewhere...

Dan Vanantwerp
08-29-2017, 08:33 PM
Hi Richard, By cement coating, are you talking ITC-100? I sprayed my interior with it and even the elements as some pottery boards were saying it helped. I had a container of it so what the heck. I'm starting to wonder if Pete is right though and the stuff is like refractory snake oil. :p I mean...how will we ever know if it helps unless we run similar furnaces side by side with and without?...no one is going to do that and in lies the magic, I fear.

Anyway, for this furnace, I got away from the pure Lauckner design and just recycled a kiln. Why?...Speed mostly. I had a show coming up and needed to get some blowing done. But also because Mark's grooved bricks are really a pain...having to perform a re-stack every time you replace elements is just unnecessary. Kilns are made to replace elements easily...more or less. Mark Jessen at Duralite even stepped up the elements to 11 gauge with a geometry that still fit the grooves. Amazingly they came out almost at a perfect length...just a little stretch required.

However, I used Mark's lid design to isolate the crucibles from the interior. My first fiberboard lid became a twisted mess...probably due to the additional area of a relatively large kiln and the extra hole for a color pot. When I added a second color pot, I decided the lid was going to need some reinforcements. I've kept my gathering ports all vertical and glad I did as the chalcedony gathers great this way. Cool thing about a used kiln...it comes with 2 pre-assembled brick maintenance lids (lid and floor of the kiln). I just cut out the crucible holes and done.

So, now I have a kastolite replacement of the fiberboard lid and a recycled kiln lid for the gathering port/maintenance lid. My actual lids over the crucibles are brick also made in Mark's design with angle iron frame, sheet metal and hose clamp tension. So far so good.

Richard Huntrods
08-29-2017, 09:31 PM
Hi Richard, By cement coating, are you talking ITC-100?

Don't know what that is. I used the same cement I used to build the lids. It's called "Super Titebond", and is a grey cement (Mark used some black stuff in his video). I dilute it about 2-1 until it's a runny slurry and paint it on. Several coats.

Anyway, for this furnace, I got away from the pure Lauckner design and just recycled a kiln. Why?...Speed mostly. I had a show coming up and needed to get some blowing done. But also because Mark's grooved bricks are really a pain...having to perform a re-stack every time you replace elements is just unnecessary. Kilns are made to replace elements easily...more or less. Mark Jessen at Duralite even stepped up the elements to 11 gauge with a geometry that still fit the grooves. Amazingly they came out almost at a perfect length...just a little stretch required.


<sigh> I'm on my second set of elements since 2003. The first set died when my first glass pot overflowed (filled too full) and killed elements and bricks. I had to rebuild.

I never used the 8ga 'garage door spring' elements Mark used because I could not get them, so a local (to Calgary) guy came over and we designed 12ga elements to give 2000W in the 1 cu. ft. space. That meant 8 grooves overall.

I used a router on a plywood table (homebuilt) with a 1/2in dovetail bit to make the grooves. They are still in perfect condition the last time I checked (less than a year ago when I built the new small lid). Wash the elements with acetone, handle with cotton gloves when installing. Same set since 2004. Many, many hundreds of hours on them now.

Sky Campbell
08-30-2017, 12:39 AM
Rudyard Kipling?


I might have been waiting to post that.

Art Freas
08-30-2017, 10:39 AM
The other driver with batch is the OSHA requirements for handling that are way more rigid if you have employees. That will drive a lot of cost every year as well.

Dan Vanantwerp
08-30-2017, 02:07 PM
<sigh> Your a funny character Richard. I think you should really consider the limited amount of glass we as hobbiests (and you, in particular) actually blow when telling everyone about how bullet proof your furnace design is. Anyone can get several years out of equipment that they seldom use. Last I read...it was too hot for you to blow glass...in Canada? I blow year-round but only on the weekends...I don't give a rip how hot it gets. That's what fans are for. Anybody should take that into account when reading about my experiences. My stuff gets pushed but not like Pete or Sky or Jordan or Eben. Someday I hope to do this full-time but I'll buy a moly when I do. Your 14 year element b.s. is just rubbing me the wrong way...cotton gloves, acetone and all. Get real.

Pete VanderLaan
08-30-2017, 02:21 PM
Actually, he's quite real and it's not BS. Ever been to Calgary in July and Aug.. ( hint it can be brutally hot)

I have clients who go through big pots like it was melting ice and I have clients who use exactly the same pots and are really careful in how they bring stuff up, how they load and I don't hear from them nearly as much.
Now it might be an irritant to you that Richard succeeds at this point but he has been getting great service and keeps on plugging at it. These days I no long have a big system and use small pots. After a bit over a year they are showing slight wear and they are always running.
If someone offers something up, don't let your nose get out of joint over it. Get more curious. I would never handle a kanthal element without gloves and I clean mine too. I would tend to use an SCR with it as well. It's worth noting that richard isn't trying to sell you anything and won't let you come and drive his MBG either. He has nothing to gain from exaggeration. I actually have elements in one kiln that have been in there since 1998. It's not a hi fire unit but twenty years is a long time.

Richard Huntrods
08-30-2017, 02:39 PM
I'm not the one who first promoted acetone and cotton gloves. Read the archives and the many long posts about it.

I'm sorry I don't measure up to your idea of perfection.

But I'm over 60 now and I really don't care. Blow it out your ass.

Dan Vanantwerp
08-30-2017, 02:51 PM
Sorry Richard. Pete makes very good points. The "<sigh>" seemed to come out of nowhere and just felt a little arrogant to me. I've always enjoyed your posts and your thoughtful approach to glass.

I would just warn people like me when I started over 10 years ago that elements typically last a year when run in a glass furnace. It's an important design consideration. Keep an extra set on hand (as well as a crucible)! Don't count on them to last a decade.

If you have built a Lauckner furnace, as I have, the brick design is fine for holding elements but bad for replacing them. My next furnace was purchased from Glass Hive and they used more of a kiln style element groove that spiraled around the crucible. When my elements went bad, I replaced them pretty easily. I hated their lid design though...nothing but 6" thick fiberfrax. Eventually a pot cracked and the whole thing was more or less ruined.

So back to my own devices and a kiln style, supped up a bit. I don't expect super element longevity but I can replace them when they eventually wear out.

My Lauckner furnace never got the chance to fail. A fire in my shop took care of that. Do everything you can to avoid that hell. It is devastating. Funny thing about glass equipment in a fire...it almost survives but not quite.

Mitcheal Veenstra
08-30-2017, 03:14 PM
well, we just bought our first round of C cullet that arrived this week. It'll probably last us a year and depending on what's going on then we'll decide.

I'm a lot less leary of mixing and melting our own glass now since the class at Corning. We'll work on the phosophate colors this winter and I'll try a few melts of clear to get a feel of what we can do with our wire melters to have options no matter which way things go.

Pete VanderLaan
08-30-2017, 03:30 PM
An important and frequently overlooked aspect of long element life is isolating the elements from the glass which does vaporize measured in micrograms per hour,. That involves a complete seal at the top of the pot.
The acid in your fingers is more than an ample source of causing element failures. We've discussed this many times prior to your arrival.
We've also discussed the importance of avoiding arcing in an element which is minimized by the use of an SCR. That we've discussed many times as well. Guage matters too. So does the glass you melt given the temperatures you have to melt at. There are lots of nuances in this little game.
Play nice or I'll let Richard run the show for a week. He'll never invite you to the Stampede and the stampede is a big deal.

Kenny Pieper
08-30-2017, 05:02 PM
well, we just bought our first round of C cullet that arrived this week. It'll probably last us a year and depending on what's going on then we'll decide.

I'm a lot less leary of mixing and melting our own glass now since the class at Corning. We'll work on the phosophate colors this winter and I'll try a few melts of clear to get a feel of what we can do with our wire melters to have options no matter which way things go.

Michael did you know that phosphate colors need to get hotter than melting clear? Its sometimes not easy to get them into solution. I would be leery doing them in a wire melter. You might need a very aggressive flux to lower the melting temp but then it will also be aggressive to your pots and melter

Pete VanderLaan
08-30-2017, 05:09 PM
I think that the substitution of Strontium for any calcium makes a really huge difference. You are no longer creating aphetite crystals which are the big ugly buggers we're so used to. If Strontium goes in, and it's not that expensive, most problems disappear. In a wire melter, I have not tried it but at 2300F it was easy. It has a similar factor as calcium so it's not hard to insert it.

Jordan Kube
08-31-2017, 12:25 PM
You make a good point, Dan, even though your delivery was a bit off. People should not expect to get Richard's longevity out of wire elements.

I've melted fluorine cullet in a wire meter before. I got about a month, maybe, out of each set. I could walk in everyday and get a different reading on my ammeter, always lower. Ed Skeels melted fluorine batches in a wire melter and got 2 weeks out of a set until he switched to gas. Moly elements are worse, you hardly get a day. I have some pretty cool pictures somewhere of a customer of Steve's who didn't heed the warning.

Bob Meyer
08-31-2017, 12:35 PM
When discussing element life, it's important to mention details like how many hours rather than years you get if you're discussing longevity. Dan has a point - a guy that fires up only on occasion (many, many hundreds of hours?) can easily have years and years on his elements, but not necessarily have bragging rights as to superior methods.

Under constant use, though (i.e., at temp continuously), I can't say I've ever heard of anyone getting past a year or two - with anything over a year (i.e., 8,000+ hours) being a real accomplishment. But my sample size is fairly small - if someone can get a consistent 15-20,000 hours out of their wire elements, I'd genuinely like to know how they do it.

Dan Vanantwerp
08-31-2017, 11:20 PM
I installed a digital chronometer from Auber on my Glass Hive furnace and got it out to 9999 on the readout. BUT...I turn it down to 1250 during the week. I'm using the same electronics on the current setup so we'll see how long they go.

My controller includes a phase angle SCR and the elements are 11 gauge. I'm cooking at 2180 so it never gets screaming hot.

That's too bad to hear about the fluorine glasses and elements. Really takes a bite out the economy of making your own color if you factor that into it.

When I visited Ed while he was in Napa he had a whole pot of opal white. I was using powder to give practically all my stuff a white undercoat at the time. The thought of just dipping a nice thick coat of white was pretty inspiring.

Terrible delivery on my part to Richard. I can't stand the way our politicians can't seem to just have a civil conversation and there I go flying off the handle. Feel like such a hypocrite and I truly apologize.

Pete VanderLaan
09-01-2017, 08:45 AM
Shielding your elements entirely in a wire melter using a sealed baffle at the pot lip would help in the short term for making fluorine glasses but that's just one part of the problem. Fluorine is totally indiscriminate in how it sees fireclays and silicates. It eats them all. My big fluorine melter in New Mexico looked like melting ice cream on the walls, crown, door, crucible, blah blah blah. When You gathered, you could get a real hit of fluorine that was like smelling slats. Nothing pleasant about it. Phosphate opals are actually far more beautiful but far harder to melt as Kenny points out. It's best done with Gas and a lot of excess horsepower. As to pots, you replace them constantly.

Your wire melters all have essentially the same issue. They're a lot like electric golf carts. Step on the pedal and you are now going at top speed and top speed isn't going to work. There's no overdrive. No free lunch or something like that.
Something Donald Carlson was doing which seemed to work quite well was having a port in the furnace into which he actually stuck a blower and literally blew the fumes out about once every few hours.

Dan Vanantwerp
09-01-2017, 10:39 AM
Well, might as well carry this discussion out to completion in terms of furnace types. Anyone try a Star Bar (SiC) furnace for making opal colors? They've got more horsepower but are they any more (or less) resistant to fluorine?

Mark Laukner made a video on a 170lb Starbar...he gave me an early copy. Such a gracious person. It involves a lot of castable...do not come to this as a first project ;)

Pete VanderLaan
09-01-2017, 11:50 AM
Star bars are just as bad except that they also react with simple silicates as well, so, worse likely. You can't melt fluorines in electric furnaces, not without dire and immediate consequences.

Dan Vanantwerp
09-01-2017, 01:54 PM
OK...for theoretical interest. Has anyone ever struck up a TIG or MIG torch/gun without the gas turned on? Immediate and pretty nasty popping due to oxidation of the hot metal be it steel or tungsten. However, turn on the gas and you're good to go. So, if you evacuated the oxygen from the element chamber on a furnace what would happen? Don't think this is undoable...argon has killed weldors working in submarines and other sealed volumes because it fills the entire vessel or at least enough to leave little or no air to breath. It is heavier than air.

https://vacaero.com/information-resources/vacuum-brazing-with-dan-kay/1172-argon-can-be-lethal.html

Hot air rises, but I'm not sure what hot argon does...

If you take Pete and Richards' suggestion of sealing the crucible chamber from the elements AND enclosing the entire lower structure in a gas proof chamber (maybe a nice, relatively thick stainless drum) could you stabilize a non-oxidizing environment around the elements. Would fluorine still attack elements in the absence of oxygen? Could a steady flow of argon be used to force out the lighter fluorine gas and keep the elements safe?

Jordan Kube
09-01-2017, 02:27 PM
Most electric heating elements rely on oxygen for their resistance to attack and aging. A1 elements form an aluminum oxide layer. You need oxygen for that. Moly elements need to be derated in a neutral atmosphere. Give this one a rest.

Dan Vanantwerp
09-01-2017, 02:37 PM
Inert gas, electric furnace (IGEF, patent pend.): RIP

Rick Kellner
09-01-2017, 03:09 PM
I'm pretty sure that altering the furnace chamber with various gases is common in industry. I seem to recall numerous references in the Kanthal literature on MoSi2 (in particular) and SiC that refer to various operating environments, and the corresponding performance specs.

Perhaps not necessarily desirable, or cost-effective at a studio scale, but apparently it's being done nonetheless.

Pete VanderLaan
09-01-2017, 03:21 PM
melting fluorines under any circumstances is a difficult proposition. Fluorine comes in a variety of monovalence forms by its nature. All release fluorine gas in varying degrees and fluorine is carcinogenic and sits atop the EPA list of bad things to breathe. So, you don't just have the furnace deterioration to consider, you have your own health as well. I really rarely melt them anymore but when I do, the building is turning over vast air changes. The Santa Fe Studio changed the air in the room once every 20 seconds. For fluorine, that's a good number.

This is a windmill best not tilted at. Either build a small gas melter so it's manageable or do it outside. Don't think electric.

Greg Vriethoff
09-01-2017, 03:34 PM
Snorting HF isn't fun.

I try not to think about all the stuff I've ingested up to this point.

Lemme tell'ya a story about this time the exhaust fan in the irridizing chamber was installed backwards,... blah, blah blah...

Dan Vanantwerp
09-01-2017, 03:43 PM
Has Dave Bross made fluorine opals in his glory setup?

Jordan Kube
09-01-2017, 03:43 PM
I'm pretty sure that altering the furnace chamber with various gases is common in industry. I seem to recall numerous references in the Kanthal literature on MoSi2 (in particular) and SiC that refer to various operating environments, and the corresponding performance specs.

Perhaps not necessarily desirable, or cost-effective at a studio scale, but apparently it's being done nonetheless.

That's what I'm referencing, Rick.

Pete VanderLaan
09-01-2017, 06:08 PM
Has Dave Bross made fluorine opals in his glory setup?
*******
Don't go looking for exceptions to some well established circumstances Dan. If you don't have the tools, or the ventilation, you really shouldn't play.

Dan Vanantwerp
09-01-2017, 06:42 PM
*******
Don't go looking for exceptions to some well established circumstances Dan. If you don't have the tools, or the ventilation, you really shouldn't play.

Fair enough, Pete. Thanks for the warning.

Sky Campbell
09-01-2017, 08:06 PM
Most electric heating elements rely on oxygen for their resistance to attack and aging. A1 elements form an aluminum oxide layer. You need oxygen for that. Moly elements need to be derated in a neutral atmosphere. Give this one a rest.

The oxide layer forms in the elements fairly quickly I wonder if they were first oxidized if they could then hold up in a oxygen free environment. Innovation never rests. It relies on doing the things that can't currently be done.

Dan Vanantwerp
09-01-2017, 08:36 PM
We need a glass "Mythbusters". I can just see those guys setting up a small prototype. I would use a vaping cigarette device in a chamber easily evacuated of all oxygen and see if it lasts longer than one exposed to air.

I'm kidding...but it would be fun :)

Jordan Kube
09-01-2017, 10:58 PM
Innovation never rests. It relies on doing the things that can't currently be done.

Agreed. I'll leave this one for someone else to try.

Dave Bross
09-01-2017, 11:04 PM
No fluorines for me. Too much trouble and danger so I spent a good bit of time and effort finding what works with phosphates. I think the etched window glass in one of the West Virginia outfits from many fluorine melts was the final hint. The fluorines also shape shift on expansion and softening temps pretty quickly if they're sitting around hot. An example would be the (now historical) Spectrum opaque cullets. You could pick them up off a hot plate no problem but if you melted them in a pot the compatibility went way off.

If you want the info on how phosphates work best there's a thread on that in antiques and classics. Don't go with the first info you find there, read to the end. You could probably remove some of the things in my final recipe there, like the borax and nitrate. Be sure you get below the suggested amount of calcium and above the suggested amount of zinc. Use strontium for the modifer to replace the calcium. Anything else that would work, like barium, is toxic and has other problems.

I usually melted the phosphates in a wire melter and they went down nicely at lower temps. They work in the glory pots too.

Dan Vanantwerp
09-01-2017, 11:51 PM
Thanks Dave. This is an excellent footnote/preface to the thread you mentioned. Phosphates it is when I go that direction.

George Vidas
09-02-2017, 01:27 AM
Kanthal actually does just as well in a neutral argon atmosphere as it does in oxidizing dry air. Presumably the oxide layer forms and doesn't dissipate.

http://www.hi-tempproducts.com/pdf/the-kanthal-furnace-mini-handbook.pdf

pp 11. "Table 3. Maximum Permissible element Temperatures in various Atmospheres."


Which brings us back to this question, from Dan V: "Would fluorine still attack elements in the absence of oxygen?"

If not, as cool as an argon flush is, you may as well just use air.

I wonder: could the efficacy of sealing the elements away from the glass with a gasket could be improved with slight positive pressure? I'm imagining harnessing the stack effect. A few small inlet holes at the bottom of the element chamber and a small vent hole at the top of the glass chamber. Maybe line that vent hole up with an exhaust snorkel.

Dan Vanantwerp
09-02-2017, 01:51 AM
Hi George, The positive pressure idea sort of gets to Pete's mention of a reverse blower port to remove the fumes periodically. A continuous system as you describe would seem the better solution. Problem with air turnover is the loss of heat...we might lower the fluorine attack but still decrease the element life by making them work harder.

Although, hot air could be recuperated from a clean source...

Pete VanderLaan
09-02-2017, 08:15 AM
As I noted, Carlson did well with the hole in the furnace simply blowing the fumes out of the furnace through a dedicated hole. The difficulty would be that an electric unit needs to be really tight to retain heat, so there's the conflict.

Randy Kaltenbach
09-02-2017, 10:48 AM
Still, if you use Richard's idea of a barrier of rammable or similar between the pot and the brick, the elements can be kept reasonably isolated from fumes. A vent in the lid can do the rest.

Dan Vanantwerp
09-02-2017, 10:55 AM
Coming back to one of the original seeds in this thread...how will Pete's unoxidized color base work with phosphate opals.

Are there things that could simply be added to achieve the melt characteristics that Dave has developed? Pete recommends a 2325F cook and it sounds like Dave has gotten this down a bit as he uses a wire melter.

I'm trying to get some opals cooking without starting a complete scratch, batch operation.

Mitcheal Veenstra
09-02-2017, 11:42 AM
my next summer studio construction project will be building a small 2 pot gas color furnace for small scale color melting. Likely a variation of the little unit that Corning let us use in class.

I was amazed in some ways at how quickly/easily we made the colors we did in class. There are a lot of stumbling blocks along the path, and I'm sure there will be many times things don't come out the way I want them to. But the mystery and fear(?) of attempting my own color has been stripped away.

I've a set of tools to explore a new world. It's pretty darn nifty.

Pete VanderLaan
09-02-2017, 11:50 AM
You're not quite getting it. The phosphate glass is an entirely different formula with similar viscosity and expansion characteristics. As a glass, it will fit both my clear formula and the clear base formula that has a good affinity for color as well.

I have melted Dave's phosphate and it's a very nice glass. It fit my basic portfolio the last time I tried it. Dave is spot on with one thing and that is to replace the calcium with Strontium. It makes what is difficult, easy. If you don't you'll see Apatite crystals everywhere. The only way to avoid hat in a calcum based phosphate is to melt at 2400F or hotter. Even so, I think it could have trouble being melted cold and I did melt it at about 2275F as I recall.

Now you will get an opal glass melting my color formula using silver but it will be a variation on many amber tones, never white. It strikes in many ways similarly to a phosphate which draws from the pot clear and then cooled substantially. Then on reheating the phase separation occurs more in the form of colloidal strands which are big molecules tending to reflect light rather than to allow light to be transmitted. They grow, they collapse, they grow again, always getting a bit fainter and that's pretty much true of any of the crystal/colloidal growth structures in glass.

Dan Vanantwerp
09-05-2017, 08:00 PM
I definitely wasn't getting it. I went back to the archives and Glass Notes to try and get a better handle on the various glass formulations and nomenclature.

Someone as unfamiliar as myself with color chemistry may not recognize that a phosphate "base" glass will be white (on striking). This was confusing me. Dave's glass is white, low-temp melting and low-devitrifying, a major accomplishment. The color threads on opal phosphates now make sense in that most of them would use a constant amount of sodium tripolyphosphate (STPP) in place of bone ash, and add colorants on top of the white. The Penland additive formulas would be used this way for the opal colors.

I'd like to get Pete's potassium clear glass batch for my normal clear, as well as my chalcedony colors, and Dave's phosphate batch to make other opal colors. This seems like the best way for me to open up a world of colors in my little two, 17 lb pot world. As I've mentioned, I don't have the facilities to store all these ingredients.

My intention now is to call East Bay and ask for a custom mix of Dave's most recent formula as follows:

"Here's what I've been melting in pounds:

Sand - 97.5
Soda Ash - 36
Hydrated Lime - 5.5
Strontium Carb. - 9
Zinc Oxide - 3
Borax 5 mol - 9
Alumina Hydrate - 4.5
Lithium Carb. - 1
Potassium Nitrate - 1
Sodium Tripolyphosphate - 6.5"

Want to be sure Dave is fine with this. I could add back the STPP separately as the Penland formula for Opal Red has a slightly lower bone ash contribution. I'm excited to get into this but know there will be many questions and don't want to step on any toes in the process.

Thanks!

Pete VanderLaan
09-06-2017, 08:05 AM
Jim may not have the STP and don't confuse it with TSP. Hydrated lime is not a generally popular form of calcium either. It may well be the case that you are not going to buy enough of the stuff to make it worthwhile for anyone to mix. Mine always came as a 1000 lb minimum. I did not recall that stuff having that much alumina in it and I'll go back and check.

In my shop, I have five base formulas that do different things but still play well together. I think John C has something like eleven now.

Dan Vanantwerp
09-06-2017, 10:47 AM
Waiting for Dave before anything. Then, I'll find out the minimum and perhaps some others have had an interest in achieving the colors Dave has described. Sounds like the STP is pretty easy to come by and may require some variable amounts based on the colors anyway.

My friend had a custom batch made up by East Bay and he sent Jim one of the ingredients. The results were not great and he figures it may not have been mixed (well) prior to bagging...similar to the SP color base.

That brings up an interesting question in batch production: is SP color base made up bag by bag? If a large amount like 1000lbs is produced and the final 50-100 lb bags are not mixed well...how does it ever get mixed? 1000 lbs of powders, flakes, crystals, etc layered into a hopper and bagged would never mix right if not mixed well prior to bagging. These must be layered in the bags and if they require mixing they were made individually.

In that case, it doesn't seem like the company should care that much if the order size is 2 bags or 50 bags. Just provide a sliding pricing scale based on volume and make it easy for small and large glass consumers to buy batch.

Pete VanderLaan
09-06-2017, 06:38 PM
My issue with SP on custom mixing has remained the same: Cleaning the mixer. At one point when I was doing color work for Josh Simpson's corona platters, he wanted SP to mix it and I said I doubted it would work. I had done the mixing at that time. It didn't work. There were some ruffled feathers and when questioned about cleaning the mixer, Tom said "You have to ask to have the mixer cleaned."
I'll leave that without comment.

The smaller your mix, the greater likelihood for error. Maybe Dave would mix and sell it to you.

SP color base isn't really mixed at all as I understand it. The proportioned chemicals are put in bags. You have to do the mixing.

Dan Vanantwerp
09-06-2017, 07:51 PM
It's pretty fascinating to hear about things like that. Good thing they are not in the food industry.

Maybe there is a future for expansion in the batch industry for someone who wants to work with the smaller glass shops. Meticulous detail and some follow up quality control sounds like a much better business model than trying to make cullet. Especially if you target the electric furnace owner and come up with something more element friendly.

I'd like to support those directly responsible for these glasses if Dave (and/or you) are interested. I'm guessing, though, that when you put the effort into making a batch you want to get the direct benefits of your hard work.

It hasn't gone unnoticed by me that you are very particular in determining the amount of screening that an ingredient needs before use. Those little "devil in the detail" things just don't show up in a recipe and can mean all the difference in success or failure. I'm also aware that going to a batch company may be hit or miss in terms of those details.

Ah well...so the adventure begins...

Pete VanderLaan
09-06-2017, 09:32 PM
Those are really rather large mixers, holding 1000 lbs or more. If something sticks behind a fin in a big batch, it's probably not that significant. A small batch is. I do ask for a clean mixer using those services and I don't use them often.
I use a small mixer these days from Home depot. For the class, we had two. They hold up to about 100lbs. It's quite serviceable for a small shop and very easy to clean and I'm rather fussy about it if I am making color mixes. If I'm running a cadmium mix I prefer to have a clear mix in between it and any other color. Sometimes I clean it with cullet and throw the cullet away. There's lots of ways to do that. I do think expecting a company used to dealing in tonnage to be even capable of doing the equivalent of craft beer isn't really a reasonable expectation.
I think dave does it in five gallon buckets actually.
And yes grain size really matters. I always use very fine screens on feldspars which I would not have thought would matter. Manganese dioxide is another one. Moisture makes some materials clump more easily than others despite how fine grain they are. I don't like clumps. Sometime try making pancakes using a joy of cooking recipe and when you get to the part where they want you to sift the flour, try it with and without sifting. Guess which one makes the better pancake?

As the German saying goes "Well mixed is half melted"

Dan Vanantwerp
09-06-2017, 11:17 PM
That German saying is pretty darn perfect...

I recall from Dave's notes as he worked through the phosphate issues that he started wetting the batch and found it helped.

Dave, I'd like to know if your latest formulation with low modifiers still likes to be wetted. AND...what is your process for doing so?

Seems like a little water in a batch would make it like a paste...or a pancake batter???

Eben Horton
09-07-2017, 07:10 AM
You might not hear from Dave for a while. He has a hurricane to worry about.

Pete VanderLaan
09-07-2017, 07:48 AM
the lime is not going to be very happy with being wet and I suspect that to be true of the alumina hydrate as well. They both already have bound chemical water. Between the soda Ash and the lime, if you get it too wet, it comes unmixed. I would try it dry before I did anything like that. I don't wet my batches at all.
The lime wet will eat your skin, fast

Dave Bross
09-07-2017, 10:21 AM
OK, first off, no manufactured batch is going to work for phosphates because the calcium content is too high. It's the calcium that turns it into chunky style sandpaper.

Second, It's just not that tough to mix small runs of batch for color. An inexpensive digital scale, a 5 gallon pail and a paint mixer on a drill work great for mixing 10-15 pounds of batch. Check your moisture contents of your materials and either compensate on your calculations or bake it out in the oven in baking dishes. Doing small batches makes the bake it out option a good one. More foolproof. You do need to be exacting on measurements due to the small batch size.

From there you'll have to do a few throwaway runs in your melter to find out what expansion is going to be required for your melter. If you insist on using the throwaways you can add alkalais (1st column of periodic table) if you're low, just keep them off the pot walls until they melt in. If you're high you can try adding zinc or boric acid. You're limited on zinc because it goes opaque around 5-6% and boric acid sometimes makes bad cords.

You'll want to track all of this on a spreadsheet. If you don't have one email me and I'll send you mine.

Water on the batch not an absolute requirement, it just helps keep the dust down. A garden pump sprayer to spray it on the batch at the end of mixing, after it's for sure thoroughly mixed, is my weapon of choice.

Gotta run for the moment. Hit me with more questions and I'll try to dig out a list of the past posts here that might help. As Eben points out, we're in full on hurricane prep and I'll get to all that when I can.

Dan Vanantwerp
09-07-2017, 11:25 AM
I'll ask some questions in line to your post...

Gotta run for the moment. Hit me with more questions and I'll try to dig out a list of the past posts here that might help. As Eben points out, we're in full on hurricane prep and I'll get to all that when I can.
Sorry that I forgot you are from Florida...stay safe!

OK, first off, no manufactured batch is going to work for phosphates because the calcium content is too high. It's the calcium that turns it into chunky style sandpaper.
I was hoping to send your latest formula to a batch maker and have them do a custom run (perhaps sans the STP). I just don't have much space to store bulk chemicals. Montana would actually be a good environment as we are very dry here. This is definitely plan B for me. I was looking for permission or to request an intellectual right percentage be established for you with East Bay. Jim mentioned this would be done for Pete's base clear. Sounds like there may still need to be some tweaking though based on the furnace...not a one off formula (addressed below).

Second, It's just not that tough to mix small runs of batch for color. An inexpensive digital scale, a 5 gallon pail and a paint mixer on a drill work great for mixing 10-15 pounds of batch. Check your moisture contents of your materials and either compensate on your calculations or bake it out in the oven in baking dishes. Doing small batches makes the bake it out option a good one. More foolproof. You do need to be exacting on measurements due to the small batch size.
Agreed, I could do this if I had the space for all the ingredients. May go down this route in the future...Thanks for the tips.

From there you'll have to do a few throwaway runs in your melter to find out what expansion is going to be required for your melter. If you insist on using the throwaways you can add alkalais (1st column of periodic table) if you're low, just keep them off the pot walls until they melt in. If you're high you can try adding zinc or boric acid. You're limited on zinc because it goes opaque around 5-6% and boric acid sometimes makes bad cords.
This is the part the that surprises me...I've got a melter that easily goes to 2100...why would my melter need a slightly different mix than your melter to achieve a ~96 COE? Is this that..."doesn't cross the street" thing I keep reading about? :) What are good ballpark percentages to add (10 lb batch, a little low, add X% Na, K, Li)?


You'll want to track all of this on a spreadsheet. If you don't have one email me and I'll send you mine.
Will do...

Water on the batch not an absolute requirement, it just helps keep the dust down. A garden pump sprayer to spray it on the batch at the end of mixing, after it's for sure thoroughly mixed, is my weapon of choice.
Another great tip but I'd try without first as Pete suggests.

Pete VanderLaan
09-07-2017, 01:17 PM
I don't view 2100F as very hot and things are going to have to be coaxed into existence with very small charges. If it was me, knowing what I know, I would in fact start with a bag of SP color base, mix it and do some simple melts. See what problems you encounter at that level. I think they could UPS you a bag of the color base. Its only difference is it contain no nitrates or antimony so it doesn't fine out well. Mess with it. A simple search here will yield up varying silver and copper ruby formulas. I did not care for those colors in the Sp87 I used for a class back in 2013 but I didn't like the feldspar and that has changed to minspar now after the Kona plant burned to the ground.

But get your sea legs first, It's not hard but it's not easy either. Process adherence is your friend. The phosphate, which if Dave or I say is easy, isn't really. You need to have a sense of when it is and isn't working. You tend to know right away. By using SP87 color base, you should have no compatibility issues initially. You'll get them once you become overconfident.

Kenny Pieper
09-07-2017, 05:10 PM
One thing to consider if you use the spruce pine batch color base is that you will need a mixer that handles a hundred lb. When they make this stuff it is measured and thrown in the bag with no mixing. You have to mix all the contents in the bag first. Then you will have to adjust for 1.7lb out of a 98 lb. formula or .6171% of sodium nitrate being missing.
But if you are going to add stp to this you will need to add silica to bring the expansion back down.

Pete VanderLaan
09-07-2017, 06:04 PM
I would use Dave's STP formulation first. It should be a separate endeavor from the SP.

Dan Vanantwerp
09-08-2017, 02:32 PM
This is a reply to Dave's latest post from the main forum. I will copy and paste in line to make things easier to follow.

East Bay has tentatively agreed to do a 200# run for me based on the ingredients of Dave's phosphate formula! So I would like to design a "pre-batch" that allows varying levels of phosphate be added to tune the color density.

Dave:
You still have to be able to figure what you're doing, pre-mixed batch or not. The sodium in STPP or whatever ride along components in other forms of phosphorous would have to be compensated for in some way without going beyond certain numbers with the pre-mixed.
It's also harder to take an expansion number down than up.

I was hoping the worksheet would help me to do this. Also, a little help from my friends...as in, if you were to make a veiled phosphate (1%) versus a full-on opaque, what would you do differently? Is the sodium loss in a veiled opal compensated for by adding more alkali? Maybe some salt?


What E&T number do you have East Bay mix it to? Even if you did something like match it to SP on E&T numbers so it had a bigger market you still have to deal with the possibility of the strain points (where the glass sets up) being different enough to cause trouble on compatibility. To not have an embarrassing situation you should batch it and melt it yourself and test the compatibility before going commercial.
I'm not trying to get East Bay to commercialize it. This is for me and anyone else who would like to try the same.

Please help me connect the dots and if I'm wrong in these assumptions let me know:
Pete has melted your phosphate and found it to be compatible with his glass.
Pete's glass is spot on with SP87. Crystalica appears to be the same. Even sounds like it is compatible with Pete's color base.

Get some cheap fireclay crucibles and figure a way to put them in your glory. Other ideas - Mark Wilson used to have a tiny glory with a shallow clay tray in the bottom to melt stuff in. He used the burner from a Turkey fryer to power it. - make a tiny gas color melter like all the guys on youtube building little forges and furnaces. a homemade burner and some kind of refractory and away you go.
This is great for prototyping but doesn't everything change when you move from furnace to furnace to glory to turkey fryer? ;)

I'd like to get the best mix possible identified that gives me the flexibility you think would allow me to get to a compatible glass under a myriad of circumstances. If I need to add a little borax or silica, I'll get some of those to make adjustments. I'd like to start with a commercial batch maker because this is the way it can work for me and my small operation.

Thanks

Pete VanderLaan
09-08-2017, 02:54 PM
And the old German adage. "A good recipe can't cross the street."

As you vary the phosphate content, you will also change the linear expansion if using STPP.. As you vary the phosphate content you will also make the glass more susceptible to turning into a sort of interesting oatmeal, kind of a slush. I'm sure Dave's seen it. It's not very marketable. It is a glass that burns out so maintaining a temperature range is important, not too hot, not too cold.
*******
A 1% phosphate is a weak phosphate. It might not even strike. You can go up to 5% reasonably. I would not be getting something mixed until I knew more of what I'm doing. I really think you should get your feet wet on easier glasses. Setting goals you cant likely achieve is not conducive to feeling pumped up. if you can't mix in studio, it's damn difficult to really alter things you don't like. People will start installing caller ID for your phone line.

Dave Bross
09-08-2017, 09:46 PM
---------------------------------------
Please help me connect the dots and if I'm wrong in these assumptions let me know:
Pete has melted your phosphate and found it to be compatible with his glass.
Pete's glass is spot on with SP87. Crystalica appears to be the same. Even sounds like it is compatible with Pete's color base.
-------------------------------------------
I'll bet Pete had to change the quantities and ended up with a different E&T number to get an exact fit. His melters are considerably more powerful than mine and he melts much larger quantities.
Pete has major skills and even some very fancy tools to check and correct a glass for compatibility.

Pay very close attention to:

" if you can't mix in studio, it's damn difficult to really alter things you don't like. People will start installing caller ID for your phone line."

You are flailing around in the dark until you master the basic skills.

That being said, I'll go at this from the very basics.

Almost any batch will work for this, including something you have mixed by others. The key numbers are no more than 3% calcium or 5% strontium while using at least .4 - 1%, but not more than 2% zinc to help retard the formation of the dreaded surface crystals. Start with somewhere around 2% phosphorous and forget about the veiled, low phosphate percentage stuff until later.

Then, unless you get lucky on the first melt and hit compatibility spot on...

For lowering expansions on future melts add more silica, to raise expansion add soda as per what you find is needed with the thread test and spreadsheet. Don't worry about correcting melts for compatibility while hot for now, just go for the correction on the next melt. That will simplify expansion corrections.

If you want the easiest way just use my recipe exactly as-is. It will work fine and be pretty close on compatibility. Correct it from there if needed.

Dan Vanantwerp
09-09-2017, 03:53 PM
I'll bet Pete had to change the quantities and ended up with a different E&T number to get an exact fit. His melters are considerably more powerful than mine and he melts much larger quantities.
Pete has major skills and even some very fancy tools to check and correct a glass for compatibility.

This made a little chill run up my spine ;)
No doubt Pete has major skills. He probably looked at your formula and immediately saw 10 different ways to skin that cat. Still, I'm hoping that for the sake of passing along data that we would all try to give the best synopsis of what was done as possible.
I'm truly a bottom feeder with very little knowledge to give. But if I tell you I did something, I did it exactly the way I tell you I did.

I've been looking for a supplier of Short MT sand all morning and just remembered why I don't want to try and source all these things. East Bay can buy in huge bulk quantities and have a good reputation for mixing. Why not use them?

I ran every batch formula I could find through your spreadsheet last night and just had a blast...by the way, your summation for batch ingredients weight stops before the STP row..need to drag the sum down to B28. I also added a little % phosphate function :)

Think I'll shut up for a while and get back with results later on. I've got two chalcedony colors going this weekend and it's time to blow. Good luck with the weather and stay safe.

Dave Bross
09-09-2017, 08:09 PM
Thanks for the heads up on the spreadsheet mistake. Giving that thing away has been a great way to find where I missed.

No need for chills up the spine. Do this:

1 - Melt whatever you decide to do

2 - Check it with thread test - if it's a striking glass like phosphate strike your blob of glass for the thread test the number of times you figure you'll strike it in use then pull the thread. The highest expansion glass is on the inside of the bend.

3 - Each millimeter of bend on the thread test is roughly equivalent to .6 in your E&T numbers

4- Play with spreadsheet, figure how much of either soda (raise E&T number) or Silica (lower E&T number) you'll need to change the E&T to where you need to go to take those few millimeters of bend out of the next thread test.

5 - Add the silica or soda to lower or raise expansion in the next melt.

6 - Melt this and check it with thread test

7 - When it pulls a straight thread then double check it with a polariscope test to be sure the strain points match closely enough. That can be done by putting a blob of it on a gather of your clear, blowing it out a bit, annealing it and have a look at it in the polariscope.

8 - Success!

The fancy toys Pete has are things like a dialatometer that will tell you the exact expansion in ten thousands of an inch and a polariscope with a built in degree wheel so you can put a number to how much strain you're seeing. These are unnecessary to get a good result at the shade tree level (that's us!) but excellent to have if you're selling something commercially and you care about high quality.

If you can't get Short Mountain sand, don't worry, get something else that's been sorted down to 200 or 325 mesh.

The short mountain makes a noticeable difference in clear colors but in opaques you get a lot of leeway because not much light is getting through so a lesser sand quality won't be visible to the eye.

Some folks get lucky on local sand. Rollin Karg gets a great sand at his masonry supplier being sold as play sand. Go figure.

Sorry if I went too far too fast too complicated on this before. It really is a simple process once you do it a few times and it gives you a wonderful level of control.

Pete VanderLaan
09-10-2017, 08:20 AM
When I wrote the section in Glassnotes IV for Henry, he asked me a question about calculations and I answered "Depending on local conditions" and he really did not like that answer but I meant it and it's a caution here:

Availability and humidity. This goes beyond what Dave has said about size of furnace. Most suppliers are going to have one source of feldspar. Almost inevitably it will be a fairly local spar and will normally be either a potash spar of a soda spar. Spodumene is a lithium spar and many pottery supplies do have it, Each plays very differently in your glass. Screen them or you'll get tiny stones since they tend to clump . The other aspect is humidity which changes your readings at the scale and that includes the scales at East Bay or Spruce Pine. Dave being in Florida would I suspect have a fair amount of water in his materials. When I worked in Santa Fe, the humidity was always under 40% so my formulas reflected that on the scales. Having 1% moisture in the silica is easy to get and that's one pound of water on the scale. Anyone using those formulas in a humid environment is a "Local Condition" Henry understood what I was saying but I'll keep saying that mixing a large amount prior to testing is dancing with the devil.

Dave can call the tools "Toys" but I bet he wishes he had one. My testing methodologies include the dilatometer but I don't necessarily use it unless I have a major problem and that can happen with high potash and fluorine mixes. The dilatometer is the only tool that is not making simple comparisons. It says what it is, no more, no less. Comparisons are really important but sometimes you are just wild ass guessing and that happens with fluorines all the time. Otherwise, I start with a simple pull test, then make a blown cup with the color inside and the clear outside, saw and score it, Then an actual Hagy seal which is well outlined in glassnotes. No single test is definitive. A Hagy seal that's out much more than 1.5 is going to break up coming out of the annealer. A pull test is only workable with similar glass formulations. Occasionally a mismatched ring test survives the saw but not often. I've seen 24 hour delays on them. The real point is that in all instances, the indicator arrow should be pointing in the same direction. Then comes the ultimate test. Sell the piece. If it's off in the slightest it will shatter at an awkward time.