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Jordan Kube 12-02-2017 06:19 PM

Encapsulated Cd-Se stains
2 Attachment(s)
These are the first results experimenting with encapsulated cadmium selenium stains in soft glass. I did some consulting work for a colored borosilicate glass manufacturer in September 2017 and saw some pretty impressive results with these compounds. The ceramics industry moved to this type of coloring for these chemicals a long time ago and could it be huge if this works in soft glass. The documentation I've read suggests 1000 times less emissions and finished glazes that are food safe.

This first experiment was done fairly loose just to give me a base line. Would any color show? If so what and how? I have about 24 of these stains and I chose 5 based on my interest in the color, mostly reds.

I used spectrum regular clear glass fritted into water out of the furnace. I mixed 200 grams clear with about 5% of each colorant. The crucibles were then filled with this mixture and brought up in my kiln to 2150 from room temperature. The kiln was held at temperature for 10 hours, a time I thought reasonable to give the fritted glass enough time to fine out. The crucibles were then cut in half and polished to better see the results.

The colors from left to right:

11.8g 4254 voilet Cr-Sn-Zr
11g 50779 Blood Red Zr-Si-Cd-Se
11.83g CT-1807 Strong Red Zr-Si-Cd-S-Se
10.34g 279615 Red Zr-Si-Cd-Se
10g 50669 Fire Engine Red Zr-Si-Cd-Se

The violet is interesting if one could get it to turn the color as seen at the top of the crucible, otherwise what it shows here in the glass can be achieved with cobalt and copper compounds.

The next step is to mix the stains into milled or powdered glass as the boro guys do and charge into a crucible that is already at temperature, as one normally would. I imagine base glass composition is important and there is literature giving some guidelines for glazes that I'm sure would apply to glass compositions as well. Proper ratios or absence of zinc, calcium, magnesium, etc.

I have a feeling mixing these into raw batches might not show results as good as these but I am purely speculating. If that is the case, custom clears could be melted and milled before additions were made.

Stay tuned.

Pete VanderLaan 12-03-2017 08:30 AM

When Chuck and I were doing the color rods, we did try the encapsulated stuff at the time. It seems to me that's a fancy word for compounded metallic and non metallic oxides and that was in use in early color work books that I have.
I do have things like Barium selenite, zinc selenite and sodium selenite which are currently in the keeping of Kenny Pieper waiting for me to drive to Penland. Cadmium needs sulfur and not in the proportion offered in CdS.
I'm not so sure about the glaze formulas being totally helpful. Glazes are thin and a pot of glass is really going to be affected by local conditions rather than furnace atmosphere if it's more than an inch thick. The photos you have indicate an incredibly light color to me or I would imagine the glasses in the pots being quite opaque against the crucible background. What were the costs on the stuff like?

The materials were sold off by Fenton glass last year which is where I got them. They had some really esoteric items like Antimony coins and I was never clear on how they would be used. Fenton did make nice colors.

In conversation with John down in Auckland, he had looked at a French company marketing the encapsulated items and said the were pretty cagey about what the materials actually were. Fero would never cop to making those frits at all. John Triggs used to make stuff up for Bullseye at Yogioheny.

I still have a rather large holding of CdS and selenium metal along with some Zinc Selenite and little demand for the colors anymore outside our own meager shop needs that I doubt I will ever get into them, but I absolutely applaud your study of it. It seems to me that the Pacific NW is certainly under scrutiny after the Bullseye/Uroboros incidents and the boro guys will continue to get watched. They have certainly made some nice reds in Boro.

I certainly do think that the base glass in soft glass is critical for success in making the color really good. For me, if the glass isn't high in Potash as well as Zinc, it's going to be a tough go to make the color look good. If one looks at selenium glasses in both soda and Potash, it's easy to see what you want to hang on to. I think the same of trying to make gold colored glasses without lead. Those are pretty good incentives to make the base glass yourself as opposed to using cullet. Cullet ties one hand behind your back at the onset.

Jordan Kube 12-04-2017 05:06 PM

You are correct about them being cagey. They will hardly tell you how to modify your formula in glazes if something isn't working.

Most of them are $25/pound. They work in glazes from 5-20%. This first round was a 5% addition. I'll be doing a test melt on Friday with a 10% addition charged at temperature instead of brought up with the kiln. Not counting the base glass, even at a 20% addition you're only looking a $5/pound in materials for colors in the $16 to $23 range.

This second test will be in 300 grams of 70 mesh spectrum regular powder. I added a mango yellow and two different erbium mixes, 5 and 10%.

OCR is also currently grinding up some cristalica for me since we'll be using that eventually. I'll be able to proof these while melting and maybe blow a bubble this time as well.

Pete VanderLaan 12-05-2017 07:55 AM


Originally Posted by Jordan Kube (Post 137597)
Most of them are $25/pound. Not counting the base glass, even at a 20% addition you're only looking a $5/pound in materials for colors in the $16 to $23 range.

This second test will be in 300 grams of 70 mesh spectrum regular powder. I added a mango yellow and two different erbium mixes, 5 and 10%.
OCR is also currently grinding up some cristalica for me

So, I take it that the intent is to make color for solid constructions as in Boro sort of things? I take it it's not for casing? It seems like it takes a lot of the stuff to get a transparent when viewed through the cut up mold. Were your tests in a soda lime or Boro?

I haven't bought cad sulfide in fifteen years at least. I doubt I'll ever have to buy it again and it's been at least that long since I paid about $4 bucks a pound for selenium, so it's all sticker shock. I know currently that about $60 dollars a pound for SE is in the range and CdS around $22.00 last time I looked. I think making 20 lbs of a very dense red took about 90 grm CdS and 43 or so on SE. I keep lowering the range to lighten the glass up around an 8/5 ratio. The base is critical. Do you have the analysis of the cristalica? If you don't I can get that to you. My main objection in it is the Borax. I never tried coloring the stuff when we brought the first loads in to Spruce Pine. Andreea had sent me a box from Dobern but I was having enough trouble just getting a clean melt. There are a few hundred pounds still down in the tractor shed and I might be able to bring the crusher up from storage there if Phil doesn't work out. Once it snows, that's much harder to do.
I'm just not clear on what the proposed application of this would be. I understand what you say about the vapor but I doubt it's going to really be that clean without a torit filter. It does seem really expensive to me.

Jordan Kube 12-05-2017 11:27 AM

Not interested in transparency. If it can be melted and gathered out of a pot, I'll be happy. You know me. If I've got a question, I'll try to answer it through experiment. Might be a dead end, might not. I have the resources to test it out right now. What got me going was the good results I saw in boro. How do they get all those colors without batching? They ball mill that stuff into dust and remelt! I walk into a shop and shake my head sometimes, there's not a lot of knowledge when it comes to equipment building and not all that much general glass knowledge but that naivete has allowed them to come up with some pretty amazing stuff. Charging powdered glass isn't something one would normally do in soft glass but if it's a tool to get certain things to work, I embrace it. We have the added advantage of being able to batch from scratch though but they are also catching up. I can tell you it's pretty intense to work in front of 2800-3000 degree equipment.

Pete VanderLaan 12-05-2017 11:46 AM

John says Zircon. He too is surprised. I'm really vested in bubble free and easily polished glass for what it's worth these days using my own color work based in glasses that are going to show color well.
Trautman was certainly the voice in the wilderness on the Boro and I do get the feeling lots of times that in the other shops it's more the Tarot Card of the fool about which I could wax eloquent.
I had one guy who was making Hagy seals entirely wrong so they were meaningless, taking the seal and fusing it from top to bottom which tells you nothing but he was selling the color at $100lb . I pointed it out and he stopped getting pots from me.
It seems to me that if you can make 2800F, you should be able to melt boro batch. Croucher does it for Abe.

But I really only want seed free/ cord free glass.

Jordan Kube 12-05-2017 12:53 PM

The kiln for hot charging is not available to me until Friday so I went ahead and loaded some more tests last night at my studio. The conditions are the same with the exception of the base glass being 70 mesh powder. Hoping for better results with a more homogeneous mixture. I'm expecting a little boil over with the powder as well. I have 13 pots with 7 different colors in various concentrations. I threw in some erbium tests at 5 and 10% additions too. I'll probably have to go to batch to get something compatible at those concentrations. In my correspondence with Eric at Uroboros he mentioned I might want to cut down on the alumina in my batches at those higher levels. His erbium casting glass was beautiful at 5%. He also told me to get rid of the calcium if I wanted a nice casting glass. I've got about 5 pounds of erbium play with.

Jordan Kube 12-05-2017 12:54 PM

"Get after it." - Pete Vanderlaan

Pete VanderLaan 12-05-2017 01:22 PM

replacing calcium in whole or in part with barium carb. the expansions are close.The ideal ratio according to Volf was 3/1. I have found that to be true. You could consider strontium as well but the barium is very bright and less pricey as well.

Eben Horton 12-05-2017 07:21 PM

Grab her by the punty Jordan :)

Jordan Kube 12-06-2017 07:41 PM

3 Attachment(s)
Oh boy. This turned out better than I could have hoped. These reds are some of the most brilliant opaque reds I've seen. The pictures don't do them justice. Friday is charging and gathering some out of pots for testing. I'm guessing the black is contamination from the cheapo assay crucibles. It foamed up and reacted with the whole side of the pot and then settled back down onto the top. I'm going to look for my small alumina crucibles for Friday.

Pete VanderLaan 12-07-2017 06:46 AM

Nice work Jordan

Jordan Kube 12-07-2017 11:14 AM

Thanks Pete.

What's really exciting about this is they all went off. There wasn't one that was kind of brown or one that got a little too orangy. The consistency from pot to pot is amazing.

Dave Bross 12-07-2017 12:30 PM

A thought along the lines of toxicity. Barium is toxic, Strontium isn't.

Excellent work Jordan.

Pete VanderLaan 12-07-2017 12:49 PM

I think of barium as toxic-lite. Strontium is about $3.75 lb.
I will be interested in the variance you get based on the surface area of the pots as you go. I would normally attribute the opacity to having a lot of cadim in the ratio. Cooling rate matters too. I hope it isn't like herding cats. You won't find much cad sel color that doesn't have first cousins with issues.

Eben Horton 12-08-2017 08:59 AM

what % did you add to the clear to make these jordan? they are beautiful!

have you measured COE yet?

Dave Bross 12-08-2017 10:47 AM

Checking my local supplier,, they've got strontium at $1.74 in 5-9 pound lots, their barium is 10 cents/lb. more.

Pete VanderLaan 12-08-2017 12:50 PM

Mine is .78. I don't really know what the strontium calcium ratio would do for the glass. It's great in phosphates, no argument there . I do know the barium/Calcium one is spot one and make the clear absolutely brilliant moreso if there's a lot of potassium. .

I think another issue that hasn't come out yet Jordan is what the slow cooling of the mix does to the opacity. I would suspect it's a major influence. If you were pulling that from the pot, It would be really nice. Mine tend to strike in the lehr and really strike if annealed twice.

Jordan Kube 12-08-2017 03:14 PM

Yes, many issues that haven't come out yet.

Compatibility testing will be done today as well.

Scott Novota 12-08-2017 04:02 PM

This is pretty cool! Where did you get those little assays from? I am interested in doing some stuff myself and those look very handy.

Jordan Kube 12-08-2017 04:11 PM

I got them from a retired spectrum glass engineer. I forgot his name. His wife was selling all of that type of stuff off and I got a good deal for a hundred or so crucibles and misc stuff.

Jordan Kube 12-08-2017 05:46 PM

The purple is cool but only works for a little while and them goes transparent blue. Gotta throw it in there and gather it out, no time to fine.

Pete VanderLaan 12-08-2017 05:52 PM


Originally Posted by Scott Novota (Post 137647)
This is pretty cool! Where did you get those little assays from? I am interested in doing some stuff myself and those look very handy.

Coorstek, or you can make your own. Kyanite and ball clay

Jordan Kube 12-08-2017 06:59 PM

Well there's no way this stuff is compatible. Imagine throwing a bunch of zirconia into your melt! The color is beatiful though. I'm probably going to have to melt my own custom clear and offset the expansion if I want to do it this way. I might hit you up for some advice Pete.

Eben Horton 12-08-2017 07:09 PM


Originally Posted by Jordan Kube (Post 137651)
Well there's no way this stuff is compatible. Imagine throwing a bunch of zirconia into your melt! The color is beatiful though. I'm probably going to have to melt my own custom clear and offset the expansion if I want to do it this way. I might hit you up for some advice Pete.

Thatís called moving the mountain to meet Mohamed ;)

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