# my first gold melt



## gubni (Dec 22, 2013)

I have access to lots of scrap gold jewelry that I send to refiners. I decided that I wanted to play with some of it.

I have a blow torch for steel work so needed a crucible and mold.

http://www.ebay.com/itm/221319927232?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

https://www.etsy.com/transaction/170554839?ref=fb2_tnx_image

I took 8.7dwt of 10k and melted it. I did not use borax. I was surprised how quick and easy it melted. I heated from above. I did get a little splatter which I was assuming was the impurities exploding. It happened more when I got the heat close. In general it melted into a blob. There were little specs that did not join the blob. Also the blob did not pour like a liquid but rather like pudding. After melting and pouring into the mold I have a 8.2dwt blob that vaguely resembles a turtle. That's about 6% loss. I'm not sure if that is because of the new crucible or because I did not use borax. I'm not really sure how the borax would make a difference anyway. I also found that I had .2dwt in little blobs still in the crucible. The crucible also appears to be covered in something that looks like a thin layer of clear dried glue. The part of the blob that touches the mold looks shiny but the other side looks black and dirty.

I welcome all comments on how to do this process better.


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## butcher (Dec 22, 2013)

The gold has a lot of base metals these can react with oxygen at that heat, and oxidize (kind of like iron rusts, or oxidizes, and is no longer iron metal which will melt), that is probably what those beads are oxidized base metal and gold mixed.

Normally it is not a good idea to remelt gold jewelry, very seldom could this be done, and try to cast another piece of jewelry, as you can see from your experiment, normally the gold is refined and mixed with the more pure base metals before being made back into jewelry.
Each time you melted this you can loose values and oxidize more base metal.

It looks like you may have burnt some carbon from the graphite, mold, I cannot see from the picture how it turned out, there are different types of graphite, some softer or will burn easier than others, some are even mixed with other metals, like copper in graphite motor brushes. 

The popping or small explosions could have been metals like zinc or something in the melt reacting with the torch.

the shiny side is probably higher gold content,the dirty side is a lot of the base metal oxides.


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## gubni (Dec 22, 2013)

The mold just has a little carbon dust that easily wiped off. I don't plan to make wearable jewelry but I do want to make small misc items of gold. My goal is to do this with little cost so refining and then adding to make it back to 10k is not feasible.

I am going to wait to do anything further until I get borax to use as a flux to prevent it from sticking to the crucible much like Pam does on a cooking skillet.


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## Harold_V (Dec 22, 2013)

Flux will absorb the oxides, yielding a cleaner button. If nothing else, the dish in which you melt should have a borax coating, which will absorb the oxides and allow the metal to flow better. This coating will rapidly become saturated with oxides and become sticky. 

The side in contact with the mold is clean and shiny because oxygen was absorbed by the carbon. Thus, the surface is free of an oxide coating. Jewelers refer to that surface as a fire coat. The black surface is the result of oxidation of base metals.

I don't have a clue what plans you have in reusing this melted material, but you're not wise in trying to do so. Once you've oxidized the base metals, the quality of the gold alloy will be suspect. It generally yields castings with inclusions, making it difficult, if not impossible, to create good surfaces. If you try polishing, you'll have tiny spots that won't shine. 

If you insist on melting your gold and re-using it for your needs, use a reducing flame on the torch, and limit the numbers of times you melt the material. Each time it is melted, it further degrades. That's unlike pure gold, which can be melted endlessly without doing damage, so long as you don't introduce contamination in the melting process. 

Harold


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## gubni (Dec 22, 2013)

Thanks for the input. For now I am just playing around mostly. One day I may try to make small 3d animals as a way to hoard gold.


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## butcher (Dec 22, 2013)

Borax or flux may help a tiny bit, you will not have much luck making new good looking jewelry out of old jewelry.

That is one of the big reasons the metals like gold is refined over and over, some of the gold in a ring may have been in a ring of an Egyptian pharaoh, no telling how many times that same gold was refined, no telling how many times it was made back into jewelry or used in some other application, like industrial material, electronics or switches...


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## ericrm (Dec 22, 2013)

butcher do you ever enconter any type of number on how much poeple died to get 1 once of gold out of the ground?


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## butcher (Dec 23, 2013)

No, but I believe it would be awful high, look at the Alaska gold rush on the Klondike, settlers traveling to the California gold rush, the Spaniards and their trips to the Incas in south America's for silver and gold, the Egyptians and their slaves, our wars through history.

I know this is not just mining gold from the ground, but these were men killed trying to get gold, keep gold, or because someone else wanted the gold.

It was not only the mining of metal that killed men,wars and conquests for the metals of power, many have been killed in relation to getting or keeping the gold throughout history, other metals in history have also been fought over. Even in our world wars gold and other metals was part of the reason of so many deaths, In a way it would be hard to put a number on how many died over gold.


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