Too much alloy? Gold is brittle and button breaks when hammering.

[Kazu]

I am making a gold ring using my grandmother's wedding ring (maybe 3 grams of 14k gold), 1 gram of pure gold flake, and ~10g of master alloy which is 71% copper 16% zinc and 13% silver.
I added the ring and flakes to a crucible, then added about twice the mass of the ring in master alloy.
After melting it down to a nice button in my forge, and attempting to hammer it while still red hot, the button breaks and is very brittle.

I took it to a local jeweler who said it burns green under his torch, and it's mostly copper.

This makes me think I've added too much master alloy and don't have enough gold.

I'm considered three options.
1) adding a half ounce of pure gold, remelting everything down in my forge, and trying to get a less brittle alloy that I can hammer into a ring
2) extracting the gold out of the broken button by crushing it and dissolving it in Aqua regia, evaporating off the liquid and trying to melt it down again with the master alloy removed.
3) sending the broken button to a gold purification business where they'll separate it out using electrolysis.


Will adding more gold make the button pliable and less brittle?

Which option would work best?

Thank you!

 

[Palladium]

https://www.911metallurgist.com/blog/gold-alloys

 

[nickvc]

When making alloys it’s always better to start with known elements so using an old 14k ring may not be ethereal best idea, my advice is to refine what you have and start afresh, working from your weights if you want to make a 14k ring you will only have enough gold for a 4.7 gram button to work with.

 

[Martijn]

Don't try any chemical refining anytime soon. Judging your options you are no where near ready for any hydrometalurgy.

And don't pollute your half ounce of pure gold with that master alloy. Where did you get that from?

Copper, silver and gold need to be annealed repeatedly in between hammering or the rolling mill.
Do this in a half dark room, to see the cherry red glow.
When annealing in sunlight you will burn the alloy before you will see it glow, making it brittle.
Quench in water while glowing to freeze the molecular structure. A lot of info on the internet about proper annealing and quenching.

Remelting an alloy over and over also makes it more brittle. Your old ring could have been a remelted piece of old jewelry.


Your best option is make a new clean alloy from part of the half once (pour shot to be able to weigh the right amount of gold) and make the carat gold with pure silver.
This will give a much softer metal to work with. You can add a bit of pure copper to get it harder. Study carat alloy's to get your desired result.
Make more than your ring's target weight.

I hobbied my wife's ring together at 22K with equal amounts of silver and copper to get a more wear resistant ring and still keep it nice and yellow. https://youtu.be/S3Nyso3BapY

Sell the brittle master alloy button for the gold or maybe someone here will refine it for you.
'Gold' brass bars with a lot less or no gold at all sell like crazy on ebay. You might even get the value of the gold and the silver back, here or on ebay.

Should you choose to refine it yourself, prepare for some serious study and have a lot of patience.

Martijn.

 

[Arthur Brown]

If you want to keep "grandmother's ring's" gold in the product you will have to refine to pure gold then very carefully return to whatever carat you want for your final product. Do careful calculations for the alloy, work out the weight of gold in the metal you start with and calculate the amount of "other metal" required for the colour and hardness you want in the product
A ring would likely be cast by a lost wax process to be about the right shape and size then minor changes can be made by hammering cutting filing and polishing.
Once you have an alloy (say 14ct) for your product then you need to work out the annealing regime for that alloy and anneal it often before final polishing

 

[jadedalex]

Kazu, you wrote:

I'm considered three options.
1) adding a half ounce of pure gold, remelting everything down in my forge, and trying to get a less brittle alloy that I can hammer into a ring
2) extracting the gold out of the broken button by crushing it and dissolving it in Aqua regia, evaporating off the liquid and trying to melt it down again with the master alloy removed.
3) sending the broken button to a gold purification business where they'll separate it out using electrolysis.

1.) I understand the sentiment of adding your G-Ma's ring to a new one. Without knowing the composition of her ring, you may be adding impurities that may make your Life harder. Refining is about purifying, not making additions...
2.) Evaporating pregnant Aqua will result in losses. The Master Alloy may contain, silver, nickel, copper and other elements that wouldn't result in any headway...
3.) Sending a small button to a Gold purification business, if they even accepted it, would cost you more money than the effort is worth. Are you absolutely sure you could afford to do so?

 

[upcyclist]

Kazu--

Remember that with gold alloys, the karat/carat rating is parts out of 24. If you mixed 1g of gold with 10g of master alloy, you have a 2 karat alloy--too much master alloy! If you want to make a 4g ring that's 14K, you need 2.34g of pure gold (14/24 * 4g), and the balance (1.66g) in master alloy.

If the gold in your old ring is 3g of 14K gold, it contains 1.75g of gold, and that's if you're sure it's actually 14K. The best you could probably do to stretch it is to downkarat it to 10K by adding 1.2g of master alloy, giving you 4.2g total.

 

[FrugalRefiner]

Remember that with gold alloys, the karat/carat rating is parts out of 24. If you mixed 1g of gold with 10g of master alloy, you have a 2 karat alloy--too much master alloy!

Picking nits, but it would be 2.18K. 1 g gold + 10 g alloy = 11 parts. 1 / 11 * 24 = 2.181818.

But yes, too much base metal.

Dave

 

[upcyclist]

Picking nits, but it would be 2.18K.

It's not nits, you just like more significant digits