Silver and Gold

[Round2potter]

Dear all,

 

I have been mixing glazes and modifying them for about a year now and i am very curious about the Coinage Metals as colorants. I know that Gold is used in cranberry glass and i have seen glassblowers "gas" a peice with silver for a blue color.

 

What colors can i get from these metals in feldspathic glazes?

 

I am more interested in silver as i can get it readily without totally breaking the bank on just a small test batch of glaze.

I have soooo many books on glazes, some new, mostly old classics, and none of them mention these pricey metals in any glazes.

 

I was going to start with a sodaspar base glaze and a potash base glaze and go from there adding modifiers etc...

What would some good starting %'s be? Do they FLUX like copper does?

 

Although i test in both electric and gas reduction, i tend to steer towards nicer RDX glazes (copper red, cobalt green, also a darkish iron, groggy body that looks great in RDX)

 

On a side note i am curious about working with the rare earths, mostly for the fun of showing people glazes glow under UV; has anybody tester gold/silver with Cerium?

 

Many thanks, hope to hear from ya'll soon

 

-Burt, Portland Orygun

[Marcia Selsor]

when you say coinage metals are you implying you would melt coins?

Amounts of copper in a glaze will vary the color tremendously from red, green blue. It also depends of the base like your soda feldspar.

Sounds like you have a lot more testing to do. I think you need to do more reading on the subject to understand the chemistry going on. If you are working on ^10 you may want to read John Britt's High Fire Glazes or Ian Currie's Revealing Glazes.

 

Marcia

[Guest JBaymore]

There is an article in the current issue of Ceramics Monthly on gold as a high fire colorant. Take a look.

 

I use gold chloride at low temerature (overglaze enamels) for reds. And for gold luster.

 

Some rare earths are in sonewhat common use. Some more unusual ones have been experimented with a bit. There are older articles in Ceramics Monthly magazine also.

 

best,

 

......................john

[Round2potter]

Oh i read John Britts book long ago, it is a go to for me when i am doing tests. As for the chemistry, i think i have a good enough grip on it all, i am a super nerdy geochemistry student.

 

And NO I AM NOT GOING TO MELT COINS, silver carbonate and goldoxides look apealing.

 

The Coinage Metals is a common name for the column in the periodic table including, copper, silver, gold and roentgenium.

 

And i am also aware they are used for lusters, but seriousey nobody has used them at stoneware temp?

 

I guess they will go orange or red, which is what i want.

 

Are they going to volatize like copper and tin?

 

Thanks!

[Round2potter]

Oh i read John Britts book long ago, it is a go to for me when i am doing tests. As for the chemistry, i think i have a good enough grip on it all, i am a super nerdy geochemistry student.

 

And NO I AM NOT GOING TO MELT COINS, silver carbonate and goldoxides look apealing.

 

The Coinage Metals is a common name for the column in the periodic table including, copper, silver, gold and roentgenium.

 

And i am also aware they are used for lusters, but seriousey nobody has used them at stoneware temp?

 

I guess they will go orange or red, which is what i want.

 

Are they going to volatize like copper and tin?

 

Thanks!

[Guest JBaymore]

And i am also aware they are used for lusters, but seriousey nobody has used them at stoneware temp?

 

I guess they will go orange or red, which is what i want.

 

Are they going to volatize like copper and tin?

 

As a chem student... you should likely head over the Digitalfire.com website and see if anything there "floats your boat". One of the best technical resources available for ceramists.

 

Nope, no volatility to speak of.

 

The reason that they are not typically used is that they are expensive, and there are cheaper alternatives to produce basically the same kinds of colors.

 

best,

 

............john

[bciskepottery]

You might want to reach out to Jon Singer -- he's done research into using phosphorous, etc. in glazes. http://71.166.254.214/ceramics/index.html

[Rebel_Rocker]

http://www.steveirvine.com/goldleaf.html

 

he uses gold leaf on pots after fire, you can also get silver leaf. I think that is the best use for them as you actually get the properties that make them so unique. You could also metal turn them, etc... for cool effects. I've also heard about using some gold in the kiln but am not sure what the process is called, it's also used for gold designs like gold leaf, but is suppose to be very tricky to get right, though it might be more permanent for dinner ware.

 

But like John said, why use gold for reds if you can use copper? I haven't mixed up an glazes personally but i imagine it would take a fair pile of gold powder to get color from it.

[Round2potter]

Ok Upon looking more into stuff written on glassware/jewelery

 

 

Silver should be reddish orange to blue depending on RDX and gold SHOULD be red in both RDX and OX.

 

 

I still have no starting percentage, so i will probably do like 1/4%-1% in 1/4% increments. or just start low and see, maybe i wont have to waste any more Au or Ag than needed.

 

NOW. The real question is what is the best (by best i mean cheapest) form of these metals that i can use.

 

Thanks all you have been a wealth of places to look.

 

And in answer to Ag, Au vs. Cu; i love copper, and copper red, i want to see first hand what the others do alone or with Cu (it would at least lessen the cost of a Gold Red.....)

[Guest JBaymore]

NOW. The real question is what is the best (by best i mean cheapest) form of these metals that i can use.

 

Gold chloride is the usual source for gold in ceramic applications. Silver nitrate is the usual choice for that metal.

 

So.... 1000 grams of glaze does not go very far.

 

IF....... (making a big assumption here) you get a nice red with a 1% by weight of of gold chloride in the base glaze, that will be 10 grams of gold chloride. 100 ml of gold chloride at only a 1% gold solution costs about $100 and weighs just over 100 grams. So the colorant alone for that 1010 gram batch of red glaze will cost about $10.

 

For the same 1000 grams of base glaze, in reduction, you can get a nice blood red with no more than about 1% copper carbonate. In the highest price bracket (buyibng a single pound) copper carb costs about $7.00 per pound. So 10 grams of copper carb will cost about $0.15.

 

best,

 

..................john

[Round2potter]

Dear John,

 

Thanks for the math on that!

although i love to fiddle with glazes, converting % and weight and balancing stuff is a headache for me, not that i cant do it.

 

I know it is expensive, its gold, i just want to make enough (~50 grams) glaze for test tile or 2. if its 10 bucks for 1 kg it'd be like 50 cents for my tests; i dont know about you but 50 cents seems worth it to me.

I know a science teacher too, so maybe i could buy only a very small amount from the school or through the school too.... we are already talking about making glazes/glass in his freshmen chemistry class this spring (they have a small furnace/kiln).

 

I dont know of you know many 9th graders, but generally they think anything with gold in it is the bee's knees; a good teaching moment.

 

Also, i am entertaining the idea of using a raw ore (after ball milling and probably magnetic purification) added to a glaze for color and a source of SiO2

 

The color and usefulness of the glaze is less important to me than just screwing around with the stuff.

 

Besides, i would have a glazed tile (red or no red) to show off to fellow glaze test junkies like myself.

 

Again,

 

Thanks John!

[Marcia Selsor]

Sorry for not being familiar with the term coinage metals...not something I ever heard used before.

It does seem like an extreme measure to use precious metals in this capacity but I understand your effort to engage your students.

Copper in reduction for a red needs about 0.5%

Manganese can give a metallic gold surface in reduction that is very enticing but not what you are looking for.

 

Good luck and post some results of the tests.

 

Marcia

[Hannahgood]

Hi I have read the convo stream with interest as i was wondering about the possibility of adding silver and or copper dust to glaze at 1260. Altho my mum has been a potter for many years and I have a basic grasp i am no chem student. I do however love to experiment and am in the fortunate position to have plenty of silver dust as i am a silversmith:-) has anyone done this ? If so what was the result ?

[Denice]

The copper dust would probably make the glaze a dark green,  I am not sure about the silver but I would imagine it would be a bubbly mess.   I had a gold ring that got caught up in the clay of a sculpture,  it was a low temp firing.  There was a black bubbly stripe down the side of the sculpture,  I scraped at it and a little gold shined through.    Denice

[Bysmerian]

On 8/16/2019 at 7:10 AM, Hannahgood said:

Hi I have read the convo stream with interest as i was wondering about the possibility of adding silver and or copper dust to glaze at 1260. Altho my mum has been a potter for many years and I have a basic grasp i am no chem student. I do however love to experiment and am in the fortunate position to have plenty of silver dust as i am a silversmith:-) has anyone done this ? If so what was the result ?

I'm tremendously interested to hear the results on this.  I made a silver chain bracelet and had a couple rings left over that were too badly bent out of shape (my fault) to even consider using for future maille projects.  I was pondering working them in with a glaze somehow (almost certainly at least breaking them up into tiny pieces with wire cutters, if not finding some way to grind them down.) and while I'm prepared to use a test tile to experiment, the kiln I have access to via my craft guild doesn't fire as often as I'd like, and it would probably be a month or more before I'd get a preliminary answer.

[liambesaw]

On 8/20/2019 at 12:46 PM, Bysmerian said:

I'm tremendously interested to hear the results on this.  I made a silver chain bracelet and had a couple rings left over that were too badly bent out of shape (my fault) to even consider using for future maille projects.  I was pondering working them in with a glaze somehow (almost certainly at least breaking them up into tiny pieces with wire cutters, if not finding some way to grind them down.) and while I'm prepared to use a test tile to experiment, the kiln I have access to via my craft guild doesn't fire as often as I'd like, and it would probably be a month or more before I'd get a preliminary answer.

Silver dust just makes black specks.  That's all!  Even silver salts when reduced as part of a lustre recipe will just yield gray to black.  The only metals that stay metallic are the noble metals.  Gold, platinum and palladium are the only affordable ones and still do not make good glaze additives.  Using their salts to dissolve them into resinous lustres is definitely possible, however making them yourself requires lab equipment and the production process releases some pretty nasty acid gases so should be done in a fume hood.

Anyway, I have been screwing around with metal salts and lustres for the past few months so feel free to PM me if you have any questions...  And the answer to the first question when dealing with silver is: yes, the stains last for a week, yes they burn and no they're not good for you

 

 

[jrgpots]

I used silver nitate and got black specks as well.  It was very unimpressive.

Jed