# Is there a min. amount of powder you should attempt melting?



## Bjc835 (Oct 28, 2014)

I ask this because I attempted melting a small amount of powder, and I could not get it to molten up, so that it could be poured. I used a propane torch for approx 25 min, and all that happened is the powder gained the color of gold, but did not fuse together, and it stuck to the crucible.


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## Anonymous (Oct 28, 2014)

Firstly did you put borax into the crucible first and "season" it so there was a glaze?

Secondly what quantity of powder did you in fact use? 

Thirdly- buy a map gas torch. It's a whole lot hotter and will melt 40g plus in a crucible with no dramas.


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## FrugalRefiner (Oct 28, 2014)

What did you try to melt it in? Crucible, melting dish, charcoal, etc.? If a crucible or melting dish, what was it made of? Did you have insulation around the container?

Dave


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## Bjc835 (Oct 29, 2014)

I don't know the exact amount in weight, but to give an idea; if you poured it onto a table top, and leveled it out, it would be enough powder to cover the surface of an american nickle.

I did use a ceramic crucible with a boric acid glaze (could this be the issue?)

Thanks for the map gas torch tip. I will surely do this.


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## Harold_V (Oct 29, 2014)

Bjc835 said:


> I did use a ceramic crucible with a boric acid glaze (could this be the issue?)


You should use borax, which is not the same compound.
The amount you choose to melt should make no difference, aside from it being difficult for miniscule globules to form a larger mass. They must come in intimate contact with one another in order for that to happen. Once you have established a globule with enough mass to roll, you can then roll it around the melting dish, picking up the balance of the globules. 

I did this routinely when melting, holding the melting dish with an asbestos gloved hand. Might not be easy to find asbestos gloves today, however. 

Harold


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## tommylee1282 (Oct 29, 2014)

just curious what are the options for good insulation around the melting dish/crucible? from reading here i know everything i shouldn't use(concrete) but off the top of my head i cant remember if ive read anything about good insulators? i use a larger version of the coffee can furnace inside a kiln with a lid at the moment to melt aluminum all the way up to silver, ive been building up my fine gold and fingers for a year now but am afraid to take the leap without having the knowledge to do it perfectly...and curious if you melt on charcoal how do you ensure the purity not going down?


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## butcher (Oct 29, 2014)

There are many different types of refractory materials, take fire brick for example some of the harder clay type refractory brick will absorb and hold a lot of heat, if you set your dish on these they can pull the heat away from your melting dish.
Soft fire brick will not absorb heat as well, and can tend to reflect the heat, the soft fire brick is normally very light weight full of air pockets in its porous nature, it is soft and can be carved easily with many of the basic hand tools, this would be a better option to sit your melting dish on.
https://www.google.com/search?newwindow=1&q=types+of+refractory+and+their+properties+and+uses&oq=types+of+refractory+and+their+properties+and+uses&gs_l=serp.12...430260.457255.0.459353.50.46.0.4.4.0.243.5132.11j30j1.42.0....0...1c.1.57.serp..28.22.2273.0.9SxzmPiRGgQ


Kaowool refractory blanket (similar to a fiber glass insulation), but made from alumina and silica fiber refractory material, its temperature ranges 2300 to 3000 deg. F (1260 to 1549 deg. C). it will not absorb heat from your ceramic dish as it has plenty of air space between its fibers, it also has a fairly high melting point, so if you do not put your torch directly to it this make a good material to sit your melting dish on.

https://www.google.com/search?newwindow=1&site=&source=hp&q=Kaowool+Blankets%2C+Board+and+Rigidizer&oq=Kaowool+Blankets%2C+Board+and+Rigidizer&gs_l=hp.12...4956.4956.0.6175.2.2.0.0.0.0.157.224.1j1.2.0....0...1c.2.57.hp..2.0.0.0.rO7Ot0cabcE

http://www.matweb.com/search/GetMatlsByManufacturer.aspx?manID=318



Air, will not suck that much heat from your melting dish, you can buy, or make a holder with a handle for your melting dish, so the dish is held in the air. or even clamped in a vise, as you melt your gold.

https://www.google.com/search?q=Melting+dishes+with+handle+and+holder&newwindow=1&source=lnms&tbm=isch&sa=X&ei=7qxRVMjMAY3piQLk94GwBA&ved=0CAkQ_AUoAg&biw=1280&bih=808 gold.

You can melt gold in carbon but it is not a wise choice if you are refining the metals...

Charcoal acts a reducer for metal oxides when melted, it will take oxygen from the base metal oxides and convert them to metal in the melt, to form CO2 gas.

If these same base metal oxides were melted in a silica dish without carbon ( and the torch flame is an oxidizing flame) they most likely would tend to stay oxides, or if metal you can turn the base metal to oxides. 

Your torch can also play a role here ,if the flame is reducing or oxidizing, with excess air or oxygen you can oxidize many base metals, with a reducing flame you can reduce metal oxide to elemental metal in the melt with the torch.

The reactivity series of metals also can play a role here of how easily the metal is reduced with carbon or oxidized with air or oxygen...


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## tommylee1282 (Oct 30, 2014)

So I'm curious how is it possible to melt gold in a potato, how does the moisture in the potato not explode like what can happen with concrete? Is the moisture just rapidly being vented? Cuz I thought the reason a potato worked was because of the moisture


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## rickbb (Oct 30, 2014)

At the temp to melt gold I don't imagine the potato would stay moist for very long. It "may" work by being burned to a crisp and therefore become a carbon crucible.

But I'm not going to try one, gold is a bit to valuable to risk losing it in a potato.


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## Geo (Oct 30, 2014)

The potato was not used to melt gold, it was used for another purpose. For safety reasons, I can't really tell you what it was used for. This forum is so big, some body may read this and try it. Trust me when I say, you can't melt gold in a potato.


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## tommylee1282 (Oct 31, 2014)

I agree about that I have a link I'll pm it to you this is where I saw it first


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## kurtak (Oct 31, 2014)

Geo said:


> The potato was not used to melt gold, it was used for another purpose. For safety reasons, I can't really tell you what it was used for. This forum is so big, some body may read this and try it. Trust me when I say, you can't melt gold in a potato.



I can see it now - someone is going to read this (above quote) & end up doing research outside this forum - find the information - & say oh I can do this

Therefore this post is intended for educational purposes ONLY :!: :!: :!: 

These are NOT instructions to a method for gold recovery & should NEVER be used as such - there are better & safer ways to accomplish the recovery of fine gold now days --- this was a method used by the old timers because back then they did not know about the dangers of being poisoned by it :!: :!: :!: 

So - WARNING --- If you try to use this method to recover fine gold YOU WILL end up POISONING your self with mercury - just like they did :!: :!: :!: 

Geo is right - the potato was not used to melt the gold - it was used as part of a recovery process for flour gold from black sands & fine gold milled from hard rock

The fine gold was first recovered from the black sands &/or crushed ore using mercury to form a gold/mercury amalgam that the sand could then be washed away from - they would then put the recovered gold/mercury amalgam in a cavity carved out of the center of the potato & then put the potato in their camp fire coals to bake it - this would evaporate the mercury off (poisonous fumes) & would leave them with the recovered fine gold which could then be melted &/or refined

What they did not know back then was the dangers of mercury poisoning they were subjecting themselves to from the simple handling of the mercury to make the amalgam to the mercury fumes when evaporating the mercury off to recover the gold from the amalgam --- its just like the Greeks that used lead goblets to drink there wine from - they liked the lead goblets because it gave the wine a sweet taste - what they did not know was they were also poisoning them self with lead

They did these thing back then because they simply did not know about the dangers of heavy metal poisoning back then 

The fact of the matter is that every single miner that used this method suffered from mercury poisoning - It Can Not Be Avoided - they just did not know what was making them sick because they did not know about heavy metal poisoning back then

Now days we know better :!: :!: :!: 

Only A Complete FOOL Would Think Of Using This Method Now Days :!: :!: :!: :!: :!: :!: 

Kurt


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## kurtak (Oct 31, 2014)

tommylee1282 said:


> I agree about that I have a link I'll pm it to you this is where I saw it first



I posted my last post in part because of this reply posted by tommylee1282

providing a link to a method that is FULL of danger is not a good idea - not even in a PM

Kurt


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## kurtak (Oct 31, 2014)

A bit about mercury poisoning - otherwise known as Mad hatter disease

http://en.wikipedia.org/wiki/Mad_hatter_disease

Kurt


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## tommylee1282 (Oct 31, 2014)

i thought from geo's post history he would be more than smart enough not to try to melt in a potato...thank you for that tidbit of info, should be a good anecdote for later in life, not to mention a reminder to always use safety


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## Geo (Oct 31, 2014)

Anyone that has ever melted and poured molten metal learns quickly that molten metal and any amount of moisture does not mix well. The molten metal can trap even tiny drops of water underneath. A small amount of water, being 2 parts hydrogen and one part oxygen, expands into a huge volume of gas. Molten metal, being in a liquid state, is hot enough to vaporize water in an instant forcing the liquid water into it's gaseous components exerting explosive forces on the soft liquid metal. This can lead to steam explosions throwing molten metal in all directions. 

tommylee1282, I looked at the pictures in the link you sent and even though it looked like whoever that was successfully melted something that looked like yellow metal in a cut potato, doesn't mean that it is in any way the right thing to do. If I had an ounce of gold and a torch and was too cheap to buy a proper melting dish, I feel I would deserve to be blinded when my gold blew up in my face.

Check this out. This is as far as I would be willing to go as far as melting without the proper equipment. I didn't want to sacrifice a usable melting dish for trash.

https://www.youtube.com/watch?v=_q-KS2EehIg&feature=youtu.be


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## rickbb (Oct 31, 2014)

I saw a documentary a couple of years ago on South American gold miners that used mercury. 

They would wash down a hill side with a high pressure hose and catch the runoff in a sluice. 

Then take the concentrates and put it in a wash tub with water, pour in a bottle of mercury and then a guy would get in the tub with bare feet and stomp the concentrate around for quite a while.

Pour off the water and mud leaving the amalgam behind. This they would put in a frying pan and cook off the mercury over a camp style propane stove.

At this point the guy looked at the camera and said, "people tell us that the fumes from mercury are bad but we believe if we breath them it will bring us luck in finding more gold". All of them then stood around and deliberately breathed in as much of the fumes as they could. A couple even passed out.

I just was like, wow, in the 21st century people believe this?


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