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Workability of Gold


#1

Well, I recently learned a “hard” lesson. I am fabricating a ring that will have bezel-set and flush-set stones. I decided to use 10k, but found it was so hard, that I had a terrible time even getting a round shape for the band. Once I started drilling holes for the flush-set stones, I gave up, and decided to use this metal in another way.

So I am moving up to a higher composition gold.

How does 14k compare to 18k in terms of workability? I don’t think companies share their specific alloy compositions (do they?). So are 14k or 18k golds from different sources equally workable?

I have a lot of experience working with sterling silver. Which gold is most like sterling silver, in terms of workability?


#2

IN my experience, 18k rose seems to work in a similar fashion to sterling. Maybe it’s because they are both alloyed with copper?


#3

Annealed gold, to someone who works primarily in silver, will seem hard. The only holds that come close to sterling in terms of hardness are maybe some high silver green golds, or high copper rose golds as it is the balance of silver and copper that lends hardness. Generally green golds are the softest of the lot. Gold alloys that come close to sterling would be 18k rose or green gold, or maybe a 22k yellow. The truth of the matter is gold is going to be harder than silver. I would reccomend a different method of setting the stone or using a higher Karat for the setting, otherwise you must learn to deal with the extra hardness. Hope this helps :slight_smile:

  • Argentum Moon

#4

You’re both saying 18k rose gold approaches the “softness” of sterling, and for this project, that would be a beautiful choice.

But how can I determine which sheet fabricator has a softer product, or do you think I’m safe with any of them?

Goldsmiths flush-set in gold all the time. It has to be do-able for me, just not in 10k (I’m curious what metals ratio that one is made up of).

Side question, why, if both fine silver and copper are very soft, does the mix create hardness? :thinking:

Thank you both very much for your input; I appreciate it.


#5

I am not a metallurgist, But I have read parts of The Theory and Practice of Goldsmithing. In the book it gives you the recipes for and shows the hardnesses of various Rose, Yellow and Green golds. The rose and greens are softer. Must be something to do with the crystal structure.


#6

In terms of a sheet fabricator, most state the hardness in vickers or brinells.


#7

@ArgentumMoon thank you, that’s great information!


#8

A way of looking at it is that silver and copper atoms move in between the gold atoms when melted into an alloy, and depending on how it solidifies, locks the atoms together in different crystal structures, which changes the malleability (how much you can deform with out cracking) and ductility (how much you can draw before breaking) of the alloy.


#9

I just looked and here are recipes for gold that have the same hardness as sterling silver. They will yield a green shade of gold (I hope that is ok)

14K Pale Green (585 Au, 382 Ag, 33 Cu)

  • 1 gram gold
  • 0.653 gram silver
  • 0.056

18K Bright Yellowish Green (750 Au, 215 Ag, 35)

  • 1 gram gold
  • 0.284 gram silver
  • 0.046 gram copper

#10

Creating my own alloys is definitely on the horizon! Thank you for these recipes. In the first example, the bottom number, 0.056, would be copper?


#11

This makes sense, and in talking about it with a non-goldsmith, but a smart guy, we figured it had to do with the particular crystal structures!


#12

Yes it is copper. Sorry about that. Here are some more recipes with their hardnesses in Brinells (HB = Hardness Brinells) the Alloys state the amount of “Master” to use, a specific amount of copper and silver pre-alloyed and meant to be mixed with their respective amount of gold. If you don’t understand something, just ask.

Silver alloys:

Reticulation silver, 80 HB, (800 Ag, 200 Cu):

  • 1 gram silver
  • 0.25 gram copper

Sterling silver, 60 HB, (925 Ag, 75 Cu):

  • 1 gram silver
  • 0.081 gram copper

Brittania silver, 52 HB, (958 Ag, 42 Cu):

  • 1 gram silver
  • 0.041 gram copper

Yellow Gold:

22k Deep Yellow, 60 HB, (917 Au, 49 Ag, 34 Cu):

  • 1 gram gold
  • 0.09 gram master

18k European Greenish Yellow, 70 HB, (750 Au, 188 Ag, 62 Cu)

  • 1 gram gold
  • 0.33 gram master

18k Greenish Yellow, 97 HB, (750 Au, 167 Ag, 83 Cu):

  • 1 gram gold
  • 0.33 gram master

18k Bright Yellow, 120 HB, (750 Au, 125 Ag, 125 Cu):

  • 1 gram gold
  • 0.33 gram master

18k Reddish Yellow, 125 HB, (750 Au, 83 Ag, 167 Cu):

  • 1 gram gold
  • 0.33 gram master

14k Greenish Yellow, 130 HB, (585 Au, 280 Ag, 135 Cu):

  • 1 gram gold
  • 0.709 gram master

14k Medium Yellow, 130 HB (585 Au, 188 Ag, 227 Cu):

  • 1 gram gold
  • 0.709 gram master

14k Reddish Yellow, 145 HB, (585 Au, 135 Ag, 280 Cu)

  • 1 gram gold
  • 0.709 gram master

10K Medium Yellow, 110 HB (417 Au, 263 Ag, 320 Cu):

  • 1 gram gold
  • 1.4 gram master

10k Reddish Yellow, 110 HB, (417 Au, 190 Ag,393 Cu)

  • 1 gram gold
  • 1.4 gram master

Green Gold:

18k Deep Green, 32 HB, (750 Au, 250 Ag):

  • 1 gram gold
  • 0.33 gram silver

18K Rich Green, 40 HB, (750 Au, 232 Ag, 18 Cu)

  • 1 gram gold
  • 0.33 gram master

18k Bright Yellowish Green, 60 HB,(750 Au, 215 Ag, 35 Cu):

  • 1 gram gold
  • 0.33 gram master

14k Pale Green, 65 HB, (585 Au, 382 Ag, 33 Cu):

  • 1 gram gold
  • 0.709 gram master

14k bright Yellowish Green, 80 HB, (585 Au, 365 Ag, 50 Cu):

  • 1 gram gold
  • 0.709 gram master

Rose Gold:

18k orange, 135 HB (750 Au, 250 Cu):

  • 1 gram gold
  • 0.33 gram copper

18k Peach, 130 HB, (750 Au, 40 Ag, 210 Cu):

  • 1 gram gold
  • 0.33 gram master

14k orange, 110 HB (585 Au, 90 Ag, 325 Cu):

  • 1 gram gold
  • 0.709 gram master

14k Red, 80 HB, (585 Au, 415 Cu)

  • 1 gram gold
  • 0.709 gram copper

10k Red, 60 HB (417 Au, 583 Cu)

  • 1 gram gold
  • 1.4 gram copper

There are the gold and silver Alloys. Here are the master Alloys. Simply match the master with the alloy (they should have the same name) and get melting.

Master alloys for Yellow Gold:

appear white-ish pink in colour until mixed with gold

22 Deep Yellow Master (600 Ag, 400 Cu)

  • 1 gram silver
  • 0.65 gram copper

18 European Greenish Yellow Master (752 Ag, 248 Cu):

  • 1 gram silver
  • 0.33 gram copper

18 Greenish Yellow Master (668 Ag, 332 Cu):

  • 1 gram silver
  • 0.497 gram copper

18 Bright Yellow Master (500 Ag, 500 Cu):

  • 1 gram silver
  • 1 gram copper

18 Reddish Yellow Master (332 Ag, 668 Cu):

  • 0.497 gram silver
  • 1 gram copper

14 Yellow Master (674 Ag, 326 Cu):

  • 1 gram silver
  • 0.483 gram copper

10-14 Medium Yellow Master (450 Ag 550 Cu):

  • 1 gram silver
  • 1.2 gram copper

10-14 Reddish Yellow Master (326 Ag, 674 Cu):

  • 0.483 gram silver
  • 1 gram copper

Master alloys for Rose Gold:

appear red in colour until mixed with gold

18 Peach Master (160 Ag, 840 Cu):

  • 1 gram copper
  • 0.16 gram silver

14 Orange Master (220 Ag, 780 Cu):

  • 1 gram copper
  • 0.27 gram silver

Master alloys for Green Gold:

appear white in colour until mixed with gold

18 Rich Green (928 Ag, 72 Cu)

  • 1 gram silver
  • 0.078 gram copper

18 Bright Yellowish Green master (860 Ag, 140 Cu):

  • 1 gram silver
  • 0.162 gram copper

14 Pale Green Master (920 Ag, 80 Cu)

  • 1 gram silver
  • 0.088 gram copper

#13

I just saw that one of the casting companies offers a metal that is half silver, and half a combination of copper and zinc. The ratio of copper and zinc changes to mimic yellow, green, or rose gold. I’m curious about anyone’s experience working with these metals, particularly about the workability.


#14

It’s 55% copper 31% Gold. The rest is zinc and silver. I haven’t worked with it because my clients prefer noble metals. I suspect that it would work like rose gold. I’d most likely want to quench while hot.
The US govt. FTC just recently decided to allow any metal with just 1% of Gold to now be called Gold. The old standard was at least 10 kt. Both MJSA and JCK have detailed articles on this.
The crazy conspiracy theory little part of my brain wonders if Tiffany and Co. had a hand in this. After all Trump named his daughter Tiffany when the largest and most lucrative tenant he had at the time of her birth was, you guessed it, Tiffany and Co. Sorry. I couldn’t Resist. I promise I won’t do that again.


#15

FWIW, Tiffany was never a tenant of Trump. Quite the other way. In order to build Trump Tower, he had to purchase the air rights over Tiffany’s building.
He had purchased the Bonwit Teller building, which he razed to build Trump Tower, from Walter Hoving, who was at the time the owner of Tiffany & Co.
So really, he paid Tiffany quite a lot to build that black glass monstrosity.


#16

@jhaemer52 are you referring to the 10k gold (“55% copper…”)?
Anyway, I did quench while hot after annealing it in a kiln. It gets rigid again really fast.

I’m curious about the 50% silver, though, alloyed to appear warmer in color than sterling. Wondering about it’s workability.


#17

I I have worked with shibuichi, a copper silver alloy with 75% copper and 25% silver. It is as hard as low karat gold and much more reactive. It will tarnish much faster than even pure copper, I assume coloured silver would be similar.


#18

I don’t think it is chemically possible for a copper-silver alloy to “tarnish faster than pure copper”. If this was your experience, I assume your samples were under different conditions. To maintain your conclusion that this is true under all conditions, you would need to be able to say why the silver in the sample would tarnish at a faster rate than copper or why copper in the proximity of silver would tarnish at a faster rate than copper alone.

Janet in Jerusalem


#19

I think it is because shibuichi is meant to be patinated, I did keep both a shibuichi ring and pure copper ring and the shibuichi ring tarnished blue and gray when the copper one merely darkened slightly.


#20

Putting a patina on shibuichi is not “tarnishing”. Tarnish usually refers to sulfides (and–less so–to oxides) formed on the surface as a result of gases in the atmosphere. I still would tend to think any changes in color had to do with how/where they were kept and how much they were handled and by whom (body chemistry can play a big role).