adding gold to batch

[Bradley Howes]

Hello All,

I was doing some research for my art history class at Alfred University and I came across a cage cup known as the Lycurgus Cup. The green photo is when the cup is lit from the front and the red photo is back lit. I was reading about the composition and it has about .0005% gold as well as silver and manganese. I'm wondering how one adds gold to glass batch. I know you have to dissolve the gold in aqua regia (very nasty). From there, historically, tin has been added to make Purple of Cassius which I believe is a powder. However, on Instagram, I saw a post where someone poured a solution, I don't know if this was the aqua regia with auric chloride or something else like a gold solution with some thing else added, straight onto the batch which was then mixed and other oxides added.

I'm really interested in this because this is a glass that becomes completely different based on how its viewed. There's a duality to the glass, similar to rare earth glasses that change color or uv reactive glasses like uranium.

[Pete VanderLaan]

Gold glasses can liver in reflective light if the molecules get big enough and I suspect that's what you are seeing. I make a gold chloride solution for my rubies and then mix it in gold sands. My friend john just pours the gold chloride into the batch,
There are three important things in the receiving batch, Gold , lead and selenium.

[Bradley Howes]

Originally Posted by Pete VanderLaan

Gold glasses can liver in reflective light if the molecules get big enough and I suspect that's what you are seeing. I make a gold chloride solution for my rubies and then mix it in gold sands. My friend john just pours the gold chloride into the batch,
There are three important things in the receiving batch, Gold , lead and selenium.

By livering, do you mean a colloidal solution is formed in the glass of gold and possibly silver nanoparticles/nanospheres? What do the lead and selenium have to do with the gold?

[Pete VanderLaan]

just to be clear. If you don't use lead and selenium in a ruby glass, at the best it will be weak in color but more likely to not strike at all. Tin is used in old formulas, I've used it but not without the prior mentioned materials.

Big molecules reflect light. Small molecules tend to allow transmissivity. You should melt a few pots of it and gain some real world understanding.

[Robert Melvin]

it is my understanding the process or gold livering is reversible by returning to a high temperature which redissolves the gold particles. Is this correct?

Also, if I wanted to work with a most beautiful and usable gold glass that is phosphate based, and no-lead, how might I locate a recipe to start with.

Originally Posted by Pete VanderLaan

Gold glasses can liver in reflective light if the molecules get big enough and I suspect that's what you are seeing. I make a gold chloride solution for my rubies and then mix it in gold sands. My friend john just pours the gold chloride into the batch,
There are three important things in the receiving batch, Gold , lead and selenium.

Color changing glass, Alexandrite. It's a whole wasps nest of philosophical quandaries. Carving cage cups must be the most labor intensive habit ever dreamed up by a glassmaker.

[Pete VanderLaan]

That's ignoring the glass in itself Mike and that's the question. What's a molecule to do?
Look at the shadows in the two pictures. One's reflective and the other transmissive.
Just melt a simple gold ruby glass. God knows it isn't rocket science anymore and you do learn a lot.

[Don Geiger]

Originally Posted by Pete VanderLaan

That's ignoring the glass in itself Mike and that's the question. What's a molecule to do?

Pete and all,

Good day to you.

Perhaps you could recommend some reading on glass chemistry?

I've studied Colored Glasses by W. A. Weyl, several digital batch books from the CMOG collection, various academic papers, and sundry articles. I've even started a small database of what chemicals are supposed to cause what results. I just cannot put it together.

There is no way I can afford to make my own glass. My plan is to mix color at the torch: again, CMOG library assistance proved the viability of this idea. John Burton demonstrated it and I think one of the students in the YouTube video is Ms. Fowler.

Please accept my apologies if this is the wrong spot to ask this question. I'm still learning my way around.

Cheers,

Don

[Pete VanderLaan]

Originally Posted by Don Geiger

Pete and all,

Good day to you.


There is no way I can afford to make my own glass. My plan is to mix color at the torch: again, CMOG library assistance proved the viability of this idea. John Burton demonstrated it and I think one of the students in the YouTube video is Ms. Fowler.

********
I can't say much. Mixing colors at a torch is not something I've done. Nominally, gold rubies require leaded glasses to make a good ruby although some literature supports the notion of a weak ruby from it. I mix up gold sands to make my base additive of gold and that's described in Fynn Lynnaard's translation of the Thuringen notes of Wilhelm Schmidt. I certainly expect that the Rakow has that book. It will only tell you about batch and additives, nothing else.

I don't know quantitatively how one would measure fuming onto glass to obtain color consistently but it sound to me like that's what you want to do. Folks do it with silver and I believe do it with either a chloride or a bromide lump. Gold as a chloride is normally in an aequous solution, not a solid, or at least I've not seen one as a solid in years. Normally gold is weighed as a "Dwt" or a penny weight. 16 pennyweights to the Oz. It's perverse.

[Larry Cazes]

Originally Posted by Pete VanderLaan

********


I don't know quantitatively how one would measure fuming onto glass to obtain color consistently but it sound to me like that's what you want to do. Folks do it with silver and I believe do it with either a chloride or a bromide lump. Gold as a chloride is normally in an aequous solution, not a solid, or at least I've not seen one as a solid in years. Normally gold is weighed as a "Dwt" or a penny weight. 16 pennyweights to the Oz. It's perverse.

Ive been torch fuming Gold and Silver on Borosilicate for 8 years now and its still not an exact science but it is a viable method. Sue Ellen Fowler actually produced a DVD some years back that outlined her techniques for torch mixing her own Boro color using clear tubing and chemical colorants. I once owned a copy but its long since been lent to others. Im sure if you search on line you can find it.

[Don Geiger]

Dear Sir,

First and foremost, thank you for your response. Your shared knowledge and time are appreciated.

Second, please accept my apology for being unclear / imprecise in what I was asking for. I am not inquiring about using fuming as a way to make colored glass at torch. Mr. Snodgrass was kind enough to answer my questions and fuming is not what I am asking about. FYI iridizing a glass vessel is classed with fuming for the purpose of my queries. Very different chemical processes and not why I am pestering you and the other people here.

The Rakow library steered my research to Suellen Fuller (Sp?) to demonstrate that making colors via torch work was possible. (She has made a lovely red cited in a CMOG YouTube video.) Her mentor was John Burton. On another YouTube video he uses Colbolt to make a blue he uses in a small drinking vessel.

Concept of the operation for making colors at the torch

With one end puntied up to a tube add the chemicals to the tube. Add a punty to the other end sealing it. Heat to a blob and using both punties mix. Then use as desired.

What reading the wisdom here has taught me is two fold.

First take the chemicals you and the others use and break them down to a percentage by weight. Such a simple concept and I just plain missed it before being permitted to subscribe here.

Second is sadly how much further my research has to go. Borosilicate as a substrate is not 96ish COE soda glass. Hence my question.

I do not mind failing or experiments going sideways. Before I start investing retirement monies, I do want a fair chance of success. Boro is weird, I like it but it is not normal from my research here and other places.

I hope you and others here can either recommend formulas based on boro glass or steer my research for how glass molecules move (word usage?) to be able to make an educated guess on how to tweak chemical components to color glass at torch using boro glass.

Sadly my research efforts have stalled. A big shout out to Schot Glass. They are focused on clarity of their product while I want to add color into it. Exploring what they are doing was insightful but Fe control is not where I want to go.

Conclusion
Once again thank you for your response and please accept my apologies for the poor way I phrased my query. What I am seeking is two fold. First, any insight or concrete ideas for which chemicals produce what colors in boro. Second, the heck with the substrate, what chemicals produce which colors and why. Sneaky third, recommended readings. If you and the members recommend it then I bloody well ought to read it too. Out of print is a tribulation and I am patient when ordering such tomes.

Cheers,

Don
PS: Your time to respond and anybody else's who responds here is highly appreciated. I was sent here by a glass provider when I pestered them, which is a high commendation.
PSS: I humongous TY to CMOG and the Raknow library staff without whose assistance I'd never have discovered glass working beyond YouTube. And, curse you Red Baron for feeding my curiosity. Fair warning Pete and all, you may also get blamed when I pester some one else next. :-)

[Don Geiger]

Originally Posted by Pete VanderLaan

********
I can't say much. Mixing colors at a torch is not something I've done. Nominally, gold rubies require leaded glasses to make a good ruby although some literature supports the notion of a weak ruby from it. I mix up gold sands to make my base additive of gold and that's described in Fynn Lynnaard's translation of the Thuringen notes of Wilhelm Schmidt. I certainly expect that the Rakow has that book. It will only tell you about batch and additives, nothing else.

I don't know quantitatively how one would measure fuming onto glass to obtain color consistently but it sound to me like that's what you want to do. Folks do it with silver and I believe do it with either a chloride or a bromide lump. Gold as a chloride is normally in an aequous solution, not a solid, or at least I've not seen one as a solid in years. Normally gold is weighed as a "Dwt" or a penny weight. 16 pennyweights to the Oz. It's perverse.

Pete,

Thanks to Larry, further on in this thread, I located Suellen Fowler demonstrating what I am interested in doing. The YouTube video is about five minutes long and she is using metallic oxides. To be blunt she and her mentor are using what I call slop chemistry. Reproducibility is problematic at best. But, based on what I've learned here I think I can get close to reproducible results.

Anyway, if you can spare five minutes here is the URL: https://www.youtube.com/watch?v=OqqMb44gg18

As always, many thanks.

Cheers,

Don