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IndustryArena Forum > MetalWorking > Casting Metals > Help with melting 24k gold foil
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  1. #1

    Help with melting 24k gold foil

    I found around 800 sheets of gold foil. I conducted an acid test and the material passed with the 22k solution (the highest one I have). After removing the foil from the paper, I had about 20 grams of gold.

    I wanted to turn the foil into a gold bar using an electric melting furnace.

    I added gold flakes to the graphite crucible and inserted the crucible into the furnace to heat up.

    The temperature reached 1065c. The material was bright red and was smoldering but had not melted. I gradually increased the temperature to 1075c but still no melting.

    I emptied the crucible and found a pile of white ash.

    Any thoughts on what went wrong?

  2. #2
    Member
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    Re: Help with melting 24k gold foil

    Hi wayne - did you use a flux? Peter

  3. #3
    Gold Member
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    Re: Help with melting 24k gold foil

    Was this foil or leaf? Foil is a lot thicker, and would melt better (especially if you used flux). Gold leaf has so much surface area compared to its volume that I wouldn't expect it to melt down into an ingot; it's like trying to melt down aluminum cans - they mostly just burn up. From your description of separating the material from its paper backing and adding "flakes", it sounds like you had leaf. That's too bad, because it's actually worth more than its equivalent weight in metal. I'm not sure why you got that ash residue, though - I would have expected it to just disappear. Was it labeled as gold foil or leaf on the packages it came in?
    Andrew Werby
    Website

  4. #4

    Re: Help with melting 24k gold foil

    Peteeng: no, I didn't use any flux. Think I should use some next time?

    Awerby: The was hand written on the box: 24K Pure Real Edible Gold Leaf Foil. Nothing from the manufacturer or anything like that.

    I tried melting some more of the flakes using a torch. The material actually caught fire.

    Looks like the foil is not gold after all. But what kind of material would look like gold flakes and also pass the acid test? When the material did not dissolve in the acid, I thought I was dealing with some quantity of gold.

    Thanks for the replies.

  5. #5
    Gold Member
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    Re: Help with melting 24k gold foil

    Apparently, it does burn; here's a mention of "high rollers" using them as cigarette papers (with a paper backing): https://abcnews.go.com/Lifestyle/gol...ry?id=20389167 ; https://www.dailymail.co.uk/femail/a...oney-burn.html

    You talk about "next time" - does that mean you have more of this stuff? I'd really advise you not to burn up the rest of it; it's pretty expensive. Sell it, and buy gold casting shot with the proceeds. https://www.slofoodgroup.com/product...f-loose-sheets
    Andrew Werby
    Website

  6. #6
    Member
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    Re: Help with melting 24k gold foil

    Hi - Metals do burn very well. Foil is very thin and so it has a large surface area to mass ratio so given some oxygen will burn. They use aluminium for rocket fuel and magnesium is well known to be careful with when machining. Aluminium battleships catch fire easily and planes do for that matter as well. Peter

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