Mabey invest in a basic thermocouple or laser temp gauge to keep track of heat. Gusts of wind will slow down the heat dramatically as well if done outdoors
Smelting Gold - How easy is it?
- Thread starter Moneybox
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Interesting line of post. Thanks.
I use a mix of Borax Soda ash & if you think there is a bit of silver add a bit of Flour (flour is added for the carbon as mentioned above)
cheers
Lee
cheers
Lee
When I smelt alloy ill use both borax and sodium carbonate ( soda ash ). What I read was the borax is to loosen the slag / impurities and help float it all, the soda ash was for degassing the melt. Without degassing, the pour would be very porous. Small bubbles..but very porous. Both borax and sodium carbonate didn't function fully ( no where near as well / clean ) unless we fully submerged the powders using a pluger to sink them to the bottom of the melt and hold it there until the bubbling stopped, which we then stir it all through a d scrape the slag. I don't know if this is of any use for gold smelting but just for some extra info I thought I'd include it in case someone picks up on something relevant 
Paul13
paul schneider
Hey moneybox did you find an explanation of this red coating?
I bought one of those small furnace and got the same redish thing..
I bought one of those small furnace and got the same redish thing..
I found when i used second grade shop bought borax it done the same to mine
Didnt matter how many times i melted it after that it would not get rid of the red and that was about 3oz
Sent it to a mate to try and do the acid process for me
Didnt matter how many times i melted it after that it would not get rid of the red and that was about 3oz
Sent it to a mate to try and do the acid process for me
Digginholes
Greg
Managed to melt some old jewellery into a blob
Goldtarget
(AKA OldGT)
Old thread but you blokes are making it look so complicated.
I'll put up the way I do it and you can decide your course of action from there. An old bloke taught me this. You need a Mapp gas torch, thick gloves, potato/s, knife, spoon, borax and quelching dish.
Get (at least) one large potato from supermarket. You can either cut the bottom flat, find a flat bottomed potato, or rest it in some clay. I prefer finding a flat bottom one and put it in a stainless steel pot.
Next using a spoon scoop out a bit at the top. About 1/2 an inch to 2 inches deep depending on how much room your gold will take up. I do 1/4 ounce melts at first, usually alluvial and pickers, so I tend to go broader and shallower until melting the 1/4 ounce buttons together.
Season the potato with Mapp torch until the hollow is blackened. Sprinkle a very small amount of borax into bottom. Put gold on top as close together as possible. Add half teaspoon of borax over top of gold as flat and even as possible.
Take Mapp torch and turn up to around 3/4 burn, and SLOWLY lower the tip of the heat. The aim here is to get the borax heated up but not blowing out gold. As it melts the borax becomes glassy and opaque greenish tinge. Slowly bring temp up over the course of 8 to 15 mins, when the potato will start glowing.
Now adjust to max heat and try with the heat to bring everything together, the gold should start glowing from a red/orange up to a bright yellow, whilst the borax will begin to peel to one side being a duller colour taking up the impurities. You know your at the right temp and getting ready to begin to add more borax or stop smelting when the two seperate "bubbles have a clearly defined edge.
Release heat immediately and let cool, after a few second to say 30 seconds the potato edges will look black and the ball will look like one piece again cooling to a blackish colour with a glassy edge. Better to wait a bit longer than not long enough to tip button from potato into quelch.
It will cool in a matter of seconds, use a spoon to fish out the button. 9 times out of ten it won't be one complete ball of gold and borax glassy covering, just chip of the borax and remelt if there's still gold in there. If I'm doing melt after melt I just put this back in the potato and add less borax to the next mix.
Eventually the potato will blast through with enough heat, but they are super cheap, bin them before blowout and prep the next. After a few melts you should have a series of buttons.
Place cool in one potato and heat slowly, as they become molten slowly add borax to skim off the last of the impurities. I've done up to one ounce bars like this with over 98% purity pretty consistently on the xrf machine. Small bars are better than big if your selling to the shop front buyers, and thinner better than thick.
Once gold has had most of its snot taken out and melted at least once it is very easy to melt again. Word of warning you can and will boil gold off if not careful. This actually doesn't take very long once it's molten, and I can tell you it's bloody hot to touch so you know, be safety minded and all.
Don't add any other metallic object in no matter how tempting I can assure you it not work out well for your tally or gold content values lol. Only handle it once quenched and cold to touch.
One bottle of Mapp gas will do around 3/4 ounce melted down comfortably which is pretty good value by the gram for processing. Supermarket borax and potatoes are next to nothing to buy, I'm still on my first jar of borax after all this time. Cheapest fastest way I know to get a result, a trip to Bunnings and to the supermarket and you are good to go.
Feel free to add anything you think I've omitted or you do differently.
I'll put up the way I do it and you can decide your course of action from there. An old bloke taught me this. You need a Mapp gas torch, thick gloves, potato/s, knife, spoon, borax and quelching dish.
Get (at least) one large potato from supermarket. You can either cut the bottom flat, find a flat bottomed potato, or rest it in some clay. I prefer finding a flat bottom one and put it in a stainless steel pot.
Next using a spoon scoop out a bit at the top. About 1/2 an inch to 2 inches deep depending on how much room your gold will take up. I do 1/4 ounce melts at first, usually alluvial and pickers, so I tend to go broader and shallower until melting the 1/4 ounce buttons together.
Season the potato with Mapp torch until the hollow is blackened. Sprinkle a very small amount of borax into bottom. Put gold on top as close together as possible. Add half teaspoon of borax over top of gold as flat and even as possible.
Take Mapp torch and turn up to around 3/4 burn, and SLOWLY lower the tip of the heat. The aim here is to get the borax heated up but not blowing out gold. As it melts the borax becomes glassy and opaque greenish tinge. Slowly bring temp up over the course of 8 to 15 mins, when the potato will start glowing.
Now adjust to max heat and try with the heat to bring everything together, the gold should start glowing from a red/orange up to a bright yellow, whilst the borax will begin to peel to one side being a duller colour taking up the impurities. You know your at the right temp and getting ready to begin to add more borax or stop smelting when the two seperate "bubbles have a clearly defined edge.
Release heat immediately and let cool, after a few second to say 30 seconds the potato edges will look black and the ball will look like one piece again cooling to a blackish colour with a glassy edge. Better to wait a bit longer than not long enough to tip button from potato into quelch.
It will cool in a matter of seconds, use a spoon to fish out the button. 9 times out of ten it won't be one complete ball of gold and borax glassy covering, just chip of the borax and remelt if there's still gold in there. If I'm doing melt after melt I just put this back in the potato and add less borax to the next mix.
Eventually the potato will blast through with enough heat, but they are super cheap, bin them before blowout and prep the next. After a few melts you should have a series of buttons.
Place cool in one potato and heat slowly, as they become molten slowly add borax to skim off the last of the impurities. I've done up to one ounce bars like this with over 98% purity pretty consistently on the xrf machine. Small bars are better than big if your selling to the shop front buyers, and thinner better than thick.
Once gold has had most of its snot taken out and melted at least once it is very easy to melt again. Word of warning you can and will boil gold off if not careful. This actually doesn't take very long once it's molten, and I can tell you it's bloody hot to touch so you know, be safety minded and all.
Don't add any other metallic object in no matter how tempting I can assure you it not work out well for your tally or gold content values lol. Only handle it once quenched and cold to touch.
One bottle of Mapp gas will do around 3/4 ounce melted down comfortably which is pretty good value by the gram for processing. Supermarket borax and potatoes are next to nothing to buy, I'm still on my first jar of borax after all this time. Cheapest fastest way I know to get a result, a trip to Bunnings and to the supermarket and you are good to go.
Feel free to add anything you think I've omitted or you do differently.
Moneybox said:
Ah so the term melt loss is true, there is a small loss of gold during the process no matter how carefully or precise one is. :Y:
G
Guest
Hi all a tip from when I started to melt a small amount of gold I used aluminium to make a hand holder for the crusable when I poured the gold out it ran back under the lip and contacted the aluminium I still have them most expensive piece of aluminium in Australia they mix easy but very hard to seperate.
i have an electric furnace so for me it is easy
BUT i started the same as OldGT in post #30 its easy and yes it does work so follow his instructions and i dont think you will go wrong
BUT i started the same as OldGT in post #30 its easy and yes it does work so follow his instructions and i dont think you will go wrong
Guys, every element has a "vapour pressure" which is higher at elevated temperatures.
We mainly associate it with liquids (water, alcohols etc), but it pertains to every element.
Our gold nuggets (just like every other element - even our skin) are slowly evaporating as I write. Just damn slowly.
Will be a lot greater at melting point and even more above.
This is not speculation, just the laws of physics.
We mainly associate it with liquids (water, alcohols etc), but it pertains to every element.
Our gold nuggets (just like every other element - even our skin) are slowly evaporating as I write. Just damn slowly.
Will be a lot greater at melting point and even more above.
This is not speculation, just the laws of physics.
If I had enough gold to smelt I'd probably buy one of the microwave smelting kits. They seem pretty straight forward and easy to use.
[video=480,360]https://youtu.be/tB3oQeTG-Mc[/video]
http://www.prospectingsupplies.com.au/products/264-deluxe-microwave-kiln-kit.aspx
[video=480,360]https://youtu.be/tB3oQeTG-Mc[/video]
http://www.prospectingsupplies.com.au/products/264-deluxe-microwave-kiln-kit.aspx
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Just remember, too much heat with an oxy, and you can vaporize your gold! Map gas and oxy mix...
https://www.prospectingaustralia.com/forum/viewtopic.php?pid=370998#p370998
https://www.prospectingaustralia.com/forum/viewtopic.php?pid=370998#p370998
Well might be taking mine back as the reviews are REALLY BAD ! Sorry for the bum steer
https://www.productreview.com.au/p/hot-devil-oxy-kit.html
Stratco has or had a special on the small map/oxy set kit $99, in SA anyway, check your State.
also on all steel camp spades (soon to be 'plug digga's)
https://www.productreview.com.au/p/hot-devil-oxy-kit.html
Stratco has or had a special on the small map/oxy set kit $99, in SA anyway, check your State.
also on all steel camp spades (soon to be 'plug digga's)
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