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.

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.

[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.

[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. :-)

[Larry Cazes]

Just for the sake of completeness for the archives a quick search shows the video on handmixed color with a torch to be "Flamework: An Intimate Art Featuring Suellen Fowler". It is still available at Firelady.com. Maybe consider using soft glass tubing and her basic techniques.

[Pete VanderLaan]

Those damn archives again!

Every single atom that goes into any given glass helps determine what colors can be made with them. There is no panacea and not even close to one. It strikes me that if you want to seal colorants in the tube, they had best be the pure metals with no oxides to gas out. You're going to need a seriously accurate scale, not one of those drug tools.
Expansion does not matter in coloring just the glass bones. Some of these atoms are quite toxic in proximity to your nose by the way.

And yes, the Ladies in the Rakow are truly remarkable. A great source of pride for me was when John Bingham, Henry Summa and I donated all the proceeds from selling the Hot Glass Information Exchange to the Rakow which allowed them to buy their first computer.

If you are indeed serious, buy Volf before it's gone.

[Larry Cazes]

I have read these messages through a few times and I still cant figure out exactly what the OP is trying to achieve Pete. Just trying to help.

[Pete VanderLaan]

That was good archive research Larry!.
It appears to me that he wants to stuff the appropriate amount of given metals, ( not oxides ) into a sealed tube and apply heat to that sealed tube and to make the color happen. I have a lot of problems with the approach, particularly given the basic glass type in the first place.

This really is not in my pay grade. Sorry.

[Don Geiger]

Originally Posted by Pete VanderLaan

Those damn archives again!

Every single atom that goes into any given glass helps determine what colors can be made with them. There is no panacea and not even close to one. It strikes me that if you want to seal colorants in the tube, they had best be the pure metals with no oxides to gas out. You're going to need a seriously accurate scale, not one of those drug tools.
Expansion does not matter in coloring just the glass bones. Some of these atoms are quite toxic in proximity to your nose by the way.

And yes, the Ladies in the Rakow are truly remarkable. A great source of pride for me was when John Bingham, Henry Summa and I donated all the proceeds from selling the Hot Glass Information Exchange to the Rakow which allowed them to buy their first computer.

If you are indeed serious, buy Volf before it's gone.

Pete,

Thank you!

Is this the Volf you recommended, Milos Bohuslav Volf?

If yes, which of his three books do you recommend I start with? The first two look very interesting but... At those prices it will have to be one at a time over a period of time. The second one looks like it might be a companion to and an update for Weyl's Coloured Glass. {I had to dig out my CRC Handbook for Weyl}

Mathematical Approach to Glass (Glass Science and Technology, Vol 9)
Milos Bohuslav Volf
ISBN 10: 044498951X / ISBN 13: 9780444989512
Published by Elsevier Science Ltd, 1988

Chemical Approach to Glass
Milos Bohuslav Volf
ISBN 10: 0983703809 / ISBN 13: 9780983703808
Published by Igneous Glassworks, 2011

Technical Approach to Glass (Glass Science and Technology)
Volf, Milos Bohuslav
ISBN 10: 044498805X / ISBN 13: 9780444988058
Published by Elsevier Science Ltd, U.S.A., 1990

Thank you for the heads up on ventilation and out-gassing.

Ventilation is way up there as a requirement.

I'd not considered out-gassing.

Measuring chemicals, yes sir.

Please correct me if I am going astray. John Burton and Suellen Fowler use a tube length of about 1/2 inch without an ID for their demos. From what I've learned here already: establish a percentage of whatever is being used to make a color for total weight used in whichever source I am working from; the way they mix the colors results in some of the punties being melted in so the weight will have to be the tube used and with some experience an estimate for the punties consumed in the process; and, it sure looks like the application will be in very few grams each.

Once again thank you for your time and shared wisdom.

Cheers,

Don

[Don Geiger]

Originally Posted by Larry Cazes

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.

Larry,

First and foremost thank you for your response.

Is this the DVD you were thinking of, Flamework: An Intimate Art? If yes, and you are looking for a replacement copy it is available at http://flameworkglass.com/SiteFiles/SFFG-Main.html

Two fuming questions.

1) Is fumed glassware safe to use with consumables like beverages and food?
2) Do you encase your fumed work?

Thank you once again.

Cheers,

Don

[Don Geiger]

Originally Posted by Larry Cazes

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.

Larry,

I found this YouTube video of Suellen Fowler mixing color at the torch. It is under five minutes long. In this one she shares the chemicals she uses to make the color too. Sighs, not how much of each but it is better than what I didn't have.

https://www.youtube.com/watch?v=OqqMb44gg18

Based on the intro glass work I'd bet this was linked to the video you recommended.

Thank you once again.

Cheers,

Don

[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

[Pete VanderLaan]

Chemical approach to Glass by Milos Volf is what you want. I also have technical glasses by Volf but I don't think it's remotely going to help. Igneous Glass in Utah reprinted the Volf. It shows up in a google search. It won't get another printing so, when it's gone, it will be gone. The original from 1980 runs well over $1,000 dollars. Obscure science.

[Sky Campbell]

I can say from my knowledge there is no toxicity related to silver or gold. Fairly safe to fume with and no toxicity problems with using a vessel fumed with either metal.

That said fuming silver and gold doesn’t work on soda lime the way it does on borosilicate. I’m not going to get into why that is maybe someone else will elaborate.

[Bradley Howes]

please pardon the lack of capitalization in this post, my shift key gave out.

Recently in my Glass Art Engine independent study at AU, I've been able to make gold ruby glasses with some success. Starting with 100g of spruce pine color base, i add .2g of black tin oxide and 1ml of dissolved gold. this gold solution has a fixed amount of gold per ml, this amount is known quantitatively. the ingredients are mixed thoroughly and then melted in an electric furnace at 1400c or 2552f. this will strike to ruby after 4 ish hours at 600-650c. when i mix 100g spruce pine with .4g black tin and 5ml, the gold strikes immediately when i pour it out of the crucible into a small graphite mold. i've also mixed an opaline gold as follows;
100g spruce pine color base
5ml gold solution aka .05g of gold
.4g black tin ox
4g stpp
1g potassium nitrate
1g boric acid

the tin helps with the solubility of gold to promote striking in the low temp range. the stpp is for opalescence. the potassium nitrate is being used as an oxidizer to keep the gold from forming metallic beads on the surface of the melt, this was a problem in an earlier melt. the boric acid was added just to balance things out a little. jacob willcox uses it in his melts to help with melting and compatibility. the two images included are lip trimmings from a vessel i made with the gold opaline.

[Bradley Howes]

Originally Posted by Sky Campbell

I can say from my knowledge there is no toxicity related to silver or gold. Fairly safe to fume with and no toxicity problems with using a vessel fumed with either metal.

i couldn't disagree more. silver fuming releases very hazardous fumes.

[Sky Campbell]

Originally Posted by Bradley Howes

i couldn't disagree more. silver fuming releases very hazardous fumes.

We have been down this road before so not sure if I care to get into another pissing match. My question is where did you get your information?

If you care to call someone out for bad information it would be nice to do it with some facts.

[Pete VanderLaan]

Originally Posted by Sky Campbell

We have been down this road before so not sure if I care to get into another pissing match. My question is where did you get your information?

If you care to call someone out for bad information it would be nice to do it with some facts.

****
Facts?, we don't need no stinkin facts!

I do tend to think that anytime your are breathing something strong enough to affect the color of a reasonably molecularly secure thing like hot glass and to actually change its color, your brain is probably interacting with the material as well. If you can smell it, you're interacting with it. I know of no cases of poisoning attributed to that process. That being said, I don't know if its bad for you but I equally find it unlikely that its good for you either. Given the known interaction with the brain that Arsenic causes ( major headaches) being off gassed from lead arsenate white enamel powder, I'd tend to use a really good ventilation booth if I was considering this.

But once again, it's not the materials we use in glass that are killing glassmakers. It's alcohol and Tobacco.

[Pete VanderLaan]

Bradley: That's very cool that you are able to do that with the SP color base. Given that you're adding the nitrates to your stuff, I doubt you really need the base. Conventionally, rubies made in a non lead base are far weaker in intensity than those made in a lead. Further, it's unusual to see rubies made without a trace of Selenium. You might try adding it. That's great work and I appreciate your thoroughness. What kinds of effects is this having on expansion.

I don't view aqua regia as being that scary. You mix it, you wear gloves, blah blah blah. Gold is normally sold by the pennyweight ( a dwt) and there are sixteen dwt in a troy ounce of gold 24 ct. I always mixed that up in a beaker with the ratio aqua regia 2 cups nitric acid, one cup hydrochloric acid added the gold shot (28 dwt) heating it gently over several days and then adding that to 100 grams per dwt silica and mashing that around . Dry it, then add it to a lead base batch.

You'll find those little ampules of gold chloride to be profoundly expensive compared to making up your own. It's true of silver nitrate as well and I make that too.

Take a look at a book that Finn Lynggaard translated from Wilhelm Schmidt in the Thuringen factory. Finn does a great job of describing the process. The book was simply called "recipes" I believe the working copies to be long gone but I would expect the library at Alfred should have a copy, a small blue hardcover book.