Refining/reclaiming gold for inlay question

[1018Machine]

I am planning on doing some gold inlay on a watch and have never done it before, one of the operations is to melt your gold (old jewelry on hand) and form it into a wire. As I understand, it then has to be annealed again to make it dead soft to inlay.

Anyone have any information? It would be greatly appreciated.

 

[Ironman]

Use a flux when melting is a good idea to trap impurities.
Borax 59%
Silica 16%
Soda Ash 14%
Flourospar 11%

Chapman flux for fine gold:
Sodium Tetraborate 40% (Anhidrous Borax)
Sodium Carbonate 20% (Soda Ash)
Manganese dioxide 20% as an oxidizer
Silica 20%

Any non-ferrous metal will work harden. Annealing is heating to a very dull red heat and quenched in water.

 

[1018Machine]

Thanks for the reply Ironman!

So, do I need to trap impurities? Is it not pure enough being already formed into jewelry?

 

[PaulL]

Gold is magical in that it doesn't work harden.
But many/most alloys of gold will work harden. Silver or copper and the other random alloying elements will do that.
So part of the question is how pure your gold is. Quick primer: a carat is a weight ratio measure out of 24 points. 24 carat is 24 points of gold out of 24. 10 carat gold is barely any gold at all (10/24th). 18 is 3/4 gold.
What's in your alloys? Who knows!

And you won't hurt gold by using an annealing process.

One of the most available sources of high purity gold is from the Canadian Mint as a gold coin. Our wedding rings came out of one. They are a bit soft.

 

[1018Machine]

Thanks PaulL! I can see one piece has a stamp of AAJ 10 kt and the other pieces have no mention of it but a quick file and magnet test show they are solid gold.

So, to be clear, if I melt them all into one piece and shape it into a round wire I should theoretically be able to hammer it into the laser engraved design and then just finish it! Yes, No?

 

[PaulL]

Thanks PaulL! I can see one piece has a stamp of AAJ 10 kt and the other pieces have no mention of it but a quick file and magnet test show they are solid gold.

So, to be clear, if I melt them all into one piece and shape it into a round wire I should theoretically be able to hammer it into the laser engraved design and then just finish it! Yes, No?

If most of it is higher carat gold, you might want to skip using 10kt, depending how much crap you want to add. The closer to pure you have the easier it will be to draw to wire and to hammer into the design.

 

[bhowden]

Not sure how much a file and magnet would tell you. Alloys are the same colour all the way through and it is unlikely any alloy would contain iron.

Brian

 

[Stuart Samuel]

Average yellow gold is, as Paul noted, a given gold content out of 24 parts, with the remainder typically being silver and copper. So the 10k is only a little over 40% gold. 10k is much, much harder than 22-24k, and would be a bear to inlay (you’d be fighting the spring back). Other colours of gold (pink, green, purple, you name it) have other elements (iron, aluminum, etc.)
White golds are alloyed with nickel or palladium as bleaching agents.

In my limited experience (trained as a goldsmith, but ended up working in custom lighting), a lack of karat marking is not a great sign. i suppose the marks could wear off?

And yes, flux. You need something to scavenge any oxides on the metal, and oxygen from the gas in contact with it (unless you’ve got some sort of inert gas furnace (which would be handy!)

 

[Ironman]

Thanks for the reply Ironman!

So, do I need to trap impurities? Is it not pure enough being already formed into jewelry?

Silver is a common impurity in that it oxidizes and as to jewelry grade gold of all and unknown description, there may be other things present, lead, silver solder, copper, etc.
Gold can be drawn out into a wire easily to do what you plan to do.

 

[ChazzC]

If you have a nearby pawn shop or gold dealer they can test the pieces and tell you the karat of each (just tell them you are interested in selling).