An Orange That Might Not Kill You

[Bradley Howes]

Hello All,

Figured I'd share another test melt I've been working on at AU. This is a variation on my earlier gold ruby. I was adding silver to try and work towards a glass like the cup of Lycurgus (I rather quickly left that in the dust to work on this). Here's the recipe I've been working with:

100 g Spruce Pine Color Base Batch
.02 g Au (used as a standard solution of gold chloride with a known weight of gold per mL with some left over acids)
.005 g Se
.5 g KNO3
.06 g AgNO3
Melted at 1450ºC for one hour in an electric carbolite furnace, poured into a graphite mold, and annealed at 500ºC. The color strikes as its cooling in the graphite mold and is quite dense. I stumbled upon how this happens in either Volf or Weyl but its only briefly mentioned. I'll update with the book and page once I find it. Below is a picture of what's left of the puck and a section of the lip that I trimmed off.

I figured I'd share this with you all since orange can be a tricky color to make without dealing with CdSSe glasses. Have fun!

[Pete VanderLaan]

It always reminded me of clean motor oil.

[Bradley Howes]

Originally Posted by Pete VanderLaan

It always reminded me of clean motor oil.

Actual mileage may vary based on your ingredients and furnace.

I settled on .06 g AgNO3 because it produced the orangest color without going greenish from the silver turning opaque.

The book reference is Weyl, Colored Glasses pg. 373. There's also a brief mention of a composition for flashing knobs by Volf in Chemical Approach to Glass, pg. 488, under the section on Technology.

[Pete VanderLaan]

I could get the color with a dirty pot and wish I hadn't. I guess I just never liked it.

[Eben Horton]

I’m not sure I’d call this orange. Seems to me like you are making gold topaz .. it looks nice !

[Pete VanderLaan]

silver can really kill gold rubies for color.

I just mistrust those 100 gram color tests as too small. I do not like to melt less than 13lbs as a test and prefer 20lb. The surface area in the pot is important in the melt since atmosphere is really important.

[Josh Bernbaum]

In my couple of tries so far, I haven't gotten gold chloride to show any color without lead being present. So I'm curious if you get any different result with just the silver nitrate but no gold in the mix.

[Pete VanderLaan]

hard way to go. The thuringen book makes one reference for a non leaded gold ruby. My take on it is that you can get silver opals to strike without reducing agents too, but it's a really expensive way to go.

I'm 71, try the lead.

[Bradley Howes]

Originally Posted by Josh Bernbaum

In my couple of tries so far, I haven't gotten gold chloride to show any color without lead being present. So I'm curious if you get any different result with just the silver nitrate but no gold in the mix.

It’s something I’ve started to poke at. I’ve seen reference to a yellow silver that is analogous to copper and gold rubies but I haven’t seen a recipe for it. I’ve given it one try so far with some success but I know I can do better after a few more tries. I think I will try a simple substitution for my next batch and see what happens. The gold ruby works for me as it currently is in the spruce pine. I would be interested to see it side by side with a leaded gold ruby and see what’s what.

[Pete VanderLaan]

you have to really dose up the silver if their are oxidizers in the batch glass. Try SP color base as an option. The ones in oxidation only strike on the surface if you reduce them at the gloryhole. Again, it's an expensive way to do things.

The base glass would be vastly improved getting the calcium out, getting zinc in.

If you don't like lead, consider Barium carb to replace it. It has some very similar attributes and is affordable

[Bradley Howes]

I’m trying a melt (another tiny 100g sample, but it’s what I’ve got right now). I’m doing 100 g SP, .05 g AgNO3, .2 g SnO, and .0075 g Se. Just changing one thing at a time right now. My previous melt was just the silver and tin and poured clear and developed some meh yellows during annealing. It was also a denser color at the bottom half of the puck whereas the top half was closer to clear. This melt is going to be closer to the gold ruby with the selenium in there. I’m not too sure how the selenium will do but I’m looking forward to seeing what happens!

[Pete VanderLaan]

I'm not surprised at the color disparity top to bottom in the pot. The upper 1/2 inch or so of a melt is affected by the kiln atmosphere and further down, it's the local conditions. Add in the disproportionate ratio of pot wall to glass and things can become quite unreliable.

[Josh Bernbaum]

You must have a good gram scale Bradley. 0.0075g? My (admittedly not the top of the line) digital one is certainly not up for that task if any accuracy is expected. I do have an old triple beam though, which I've just never used yet, and can't remember how low it goes.

[Pete VanderLaan]

The law of significant figures comes into play at this level, another of my objections in small batch.

[Jed Hannay]

Originally Posted by Bradley Howes

I’m trying a melt (another tiny 100g sample, but it’s what I’ve got right now). I’m doing 100 g SP, .05 g AgNO3, .2 g SnO, and .0075 g Se. Just changing one thing at a time right now. My previous melt was just the silver and tin and poured clear and developed some meh yellows during annealing. It was also a denser color at the bottom half of the puck whereas the top half was closer to clear. This melt is going to be closer to the gold ruby with the selenium in there. I’m not too sure how the selenium will do but I’m looking forward to seeing what happens!

Sounds like a pretty solid process. I’m looking forward to seeing what happens, too.

Yellow silver sols analogous to copper and gold rubies will follow the same fundamentals (weyl p.365). Gold sols are relatively insensitive to the redox state, but copper and silver are not. (Weyl p.405 factors affecting equilibrium of Ag+ and Ag etc)

Volf isn’t much of a fan of silver glasses but as you’ve found there’s a bit at p487 and the top of 488. He mentions Sb, but I wouldn’t.

Starting with AgNO3 introduces additional O2 and complicates the redox process from the get-go (that may be subjective) Decide if you’re trying to make mirrors or pyrosols.

Homogeneously nucleated amber silver sols work ok, as you’ve found. Adding volatile Se in minute amounts may complicate repeatability.

The color variation in your puck is possibly due to the thermal history gradient and not compositional inhomogeneity.(edit: I may not be tracking your process. I thought the puck was cast?)

[Pete VanderLaan]

I agree that the additional oxygen in the silver nitrate is not your friend but I have yet to find anything ( and haven't tried hard) to replace the method of introducing the silver. It is easy enough to get it to go totally metallic, sink to the bottom and drill a hole and that's worth avoiding. The variations on silver compounds are easy enough to make but the only one that would appeal to me at all would be the chloride. I'd expect that to burn the chlorine right out and leave an oxide but to have assisted somewhat in pacifying the goop. The bromide is hopelessly insoluble. I have not thought about the iodide.

Agreed that Volf simply dismisses silver which I find rather curious unless you consider it's lack of predictability historically. Weyl spends precious little time on it. Norbert Kreidle used to say it was too expensive. Simply put, it gives wildly differing results each time you try it. Industry is not fond of that. We are usually.
If the Selenium is doing anything, it's making the melt attractive because of the valences it offers. It's rare to see a gold glass without selenium. The seeds are the truly irritating issues in these silver glasses. Why the silver based glass is so difficult to fine out would be a great thing to overcome. This still needs larger samples.