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Melting Gold

I have tried several times to melt scrap gold just to get a feel of how it flows in its liquid state and to no luck - I can’t get it to turn into a running metal. Different sources say gold melts around 1800° to 2000° - yet I have had it there and still not pouring in a pure liquid state… any suggestions?

700 ° C to 1000 ° C degrees are more than enough, depending on the carat.
do not experiment more at higher temperatures because you will have gram metal losses, its burning.
find someone and watch them how melt for once and you will get better.
don’t forget the borax.

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Pure Gold melts at 1064 centigrade and boils at 2700 centigrade.

18 karat at 926
14 karat at 879
All according to Google :slight_smile:

So 1000 centigrade should be sufficient for karat gold to get a good flow, it actually may be too low for 18 karat with 70 degrees over melting.
2000f should be plenty as long as it is not pure.

Pure Gold do not need borax, but karat gold may need some borax for protection.
Be sure to have the melting dish glased with borax though.

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What kind of torch are you using? Preheating your crucible? Is it glazed? Did you use borax? The more information that you can provide the more accurate the diagnosis.

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One common cause of problem is utilizing the heat you are putting in.
Most torches may get hot enough, but may fail to put in enough btu to actually heat the metal sufficently.
Keep your melting dish on an insulated surface.
Firebrick or similar, have the same behind and on the sides to reflect the heat back to the melting dish. If karat Gold, use enough borax to keep the metal covered but not too much.
Of course the dish should be glazed prior to melting.
If this do not solve your problems, you will have to explain in detail what you are doing so we can see what is causing your problems.
A google search may solve a lot too.

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Temperature and heat are two different things. Your torch may get hot enough but not produce enough heat to get the metal hot enough to melt. That is confusing, but I used to teach Physics. Others have posted lots of suggestions to capture and keep the heat that your torch produces around your crucible. Your only other choice is a bigger torch that produces more heat. I can easily melt sterling silver and any karat gold in small quantities up to 2 ounce with my Meco torch. I can’t melt copper and brass in any quantity because my torch doesn’t produce enough heat. Good luck…Rob

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How much gold are you trying to melt Michael? I have melted and cast 2.5 oz sterling silver many times and have done 0.5 oz of 14k gold twice and had no problem with the smith little torch with the rosebud tip.

You might try a very small quantity and see if that makes a difference. My first time melting silver I had way too much in the crucible and the smith little torch was unable to melt it no matter how long I heated it. This is a direct example of the heat vs temp explanation that Rob offered.

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One thing that hasn’t been covered is how you heat. The hottest part of the flame needs to play over the metal. This area is right in front of the small blue cone. If you are putting the torch too close or using the flame too distant from the small blue cone, you won’t get the greatest heat from the torch. -royjohn

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Thanks for all the responses - this is why this community rocks. I’m trying to melt roughly 9/9.5 grams of scrap 10 kt gold. I am using a Kerr Electro Melt furnace that has a peak of 2200 degrees - yet when it reaches that temperature and I go to pour - its not as liquid like as videos I have watched that use the same unit. It seems to still be semi solid - I have tried it after 5 min, 10 min - still the same.

An electric melting furnace should melt your metal as long as you set it for the proper temperature to get the metal to a liquid state. If the metal is still partially solid and partially liquid, then your metal is at the solidus/liquidus threshold: not really solid, and not really liquid. Raise the temperature about 20 degrees and that should do the trick. If it doesn’t, my next questions is whether of not your pyrometer is still accurate. How old is your furnace? The two parts that most frequently need replacing - other than the graphite crucible are ( and usually in this order) the heating element, and the pyrometer. Hope this helps.
Mike

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I have attempted that roughly 30 min ago and still coming out semi solid - the furnace is in good condition, no cracks, crucible is basically new & this is 10kt scrap gold. This electro furnace is rated for 2200° - how long should scrap gold sit in the temperature for if you have any suggestion?

Is it possible that your scrap really isn’t gold? Try to torch melt it in a small crucible or even on a charcoal block and see how it behaves. As long as your torch is up to it, the gold should puddle up quickly into a flat ball. If it does, there is probably something off about your electric furnace. If it doesn’t, it may not be gold.

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hi rob,
i love the way you think…i aspire!

julie

If I were you I would try melting some known silver or gold and see what happened. It’s either the metal you are melting that is the problem or your Kerr is not coming up to temperature. Those Kerrs are mostly rather old now (They don’t make them anymore, right?) and perhaps it isn’t working right, and is showing a temperature that it isn’t actually reaching. If the heating element is in good shape, it could be a flaw somewhere in the circuitry. I was advised not to get one of these because I was told there wasn’t anyone repairing them now, but perhaps that isn’t correct… -royjohn

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it was a steal at $10 to buy, the gold I melted somewhat* was acid tested and with the thermo gold gun and was registering 10.3 karats -

If you are saying that you paid $10 for 9 grams of 10 K gold, you either got a great deal or taken. Go to one of the many online scrap calculators and see what it should be worth.

The Kerr electromelt was $10 - just to clarify

Have you tried a smaller amount of the same metal?