# Melting gold with torch



## Geo (Aug 1, 2017)

My video of melting gold by hand with a cutting torch. As of late, I no longer stress the purity because the refinery pay 98% spot on assay. That particular gold was 99.2% pure. I don't know what discolored the end unless it was the carbon from the mold. 

https://youtu.be/PGx11OQQOa4


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## snoman701 (Aug 2, 2017)

Geo said:


> My video of melting gold by hand with a cutting torch. As of late, I no longer stress the purity because the refinery pay 98% spot on assay. That particular gold was 99.2% pure. I don't know what discolored the end unless it was the carbon from the mold.
> 
> https://youtu.be/PGx11OQQOa4



Are they paying by fire assay or by xrf?


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## glorycloud (Aug 2, 2017)

:lol: :lol: :lol: 

Gold powder melted in less than ten seconds by Geo!!

The video of Glory_Cloud melting gold powder with MAPP gas
would be about ten minutes in length including time for an 
intermission as needed!! 

:lol: :lol: :lol:


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## g_axelsson (Aug 2, 2017)

If they pay by XRF on the surface then a quick boil in sulfuric acid could get your percentage up. The oxide layer that gives the discoloration would report extra much in an XRF as it only measures the composition skin deep and the surface makes the largest contribution.

If they are filing down a bit and measures the fresh surface then it doesn't matter.

As for what the surface contamination could be, I would guess copper or maybe iron if you use copperas to drop the gold. Silver wouldn't make an oxide layer. Carbon isn't a suspect in this case, the oxide is a gas and there are no carbon gold compounds that I know of that would survive that kind of heat and environment, it would just oxidize away. 

That video is a great example of how the proper tool makes a job easy. I always use acetylene for every serious melt nowadays.

Göran


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## Geo (Aug 2, 2017)

XRF but this thing is as big as a refrigerator. It has a lid over half of it that needs a strut to support it as it opens and closes. It has a target with a cross hair that looks like a rifle scope. You place the sample on the cross hair and close the lid and push the start button. It prints out a report of the content and payout. 

The torch has a propane tip in it so I'm using oxy/propane. The crust that formed as it melted must be the contamination. I thought it was just sodium chloride. I use one of those green ScotchBrite scrub pads to polish the top and bottom so it has a good metal surface when they shoot it.


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## rewalston (Aug 2, 2017)

One of these days I need to get an oxy/propane setup. Right now I use MAPP. No way to go get a decent oxy tank except for those tiny ones from the hardware store.
Rusty


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## Geo (Aug 2, 2017)

Well, here in Alabama, you can rent or buy oxygen cylinders from any welding supply store. I don't know what kind of laws in Canada might effect that. The pros and cons of renting as apposed to owning. Con : You owe the monthly rental whether you use it or not. Pro : The rent here is just a few dollars per month. The last bottle I rented was like $6 per month. Con : If you buy a bottle, it will have to be tested periodically before it can be refilled. Pro : If you rent, you get a good bottle every time with no need to test it. 

There is always Ebay. You can get a torch kit that includes the cylinders for a few hundred dollars shipping included.


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## rewalston (Aug 2, 2017)

Geo said:


> Well, here in Alabama, you can rent or buy oxygen cylinders from any welding supply store. I don't know what kind of laws in Canada might effect that. The pros and cons of renting as apposed to owning. Con : You owe the monthly rental whether you use it or not. Pro : The rent here is just a few dollars per month. The last bottle I rented was like $6 per month. Con : If you buy a bottle, it will have to be tested periodically before it can be refilled. Pro : If you rent, you get a good bottle every time with no need to test it.
> 
> There is always Ebay. You can get a torch kit that includes the cylinders for a few hundred dollars shipping included.


Thanks Geo, I'll check Ebay out


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## upcyclist (Aug 2, 2017)

At my jeweler's guild here in Maryland, we have owned a minimal set of bottles for years (one Smith mini oxy/acetyl, and 4 acetylene torches). We take the empty ones in to Roberts Oxygen, and exchange them for a filled bottle for just the cost of the gas. We've had them so long it hardly matters how much the initial bottle cost.


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## Palladium (Aug 2, 2017)

There's a fellow at Mountain Top Trade day that sells them Jeff. I gave $50 for one that was already certified. I took it to my local welding supply store and swapped it out for a full bottle. It cost me $12 to swap it out each time and i still own the bottle even though it ain't the one i originally bought. With that i have a gas bbq grill bottle that cost $20 to swap out anywhere. Then stop by ebay and get a torch and regulators with the hose and tips for $100. Total cost probably $200 time and all. You can melt a lot of gold and silver before you ever have to swap out a bottle. The rig basically pays for itself and i would recommend anyone who's buying very many of the small mapp gas bottles to upscale. It makes life sooooo much easier!


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## Geo (Aug 2, 2017)

I have a large O2 bottle. I forget the name on the collar but I get mine filled at AirGas in Decatur. It cost $15 to fill. I have to drop it off and come back to pick it up. They do not exchange. It's $45 to test a bottle in their well. They will certify it and stamp it right there. I still find bottles with a swastika stamped in it with the year beside it. They are long lived.


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## SStafoscolton2 (Sep 6, 2017)

I have my gold dust but when I went to smelt. It was magnetic. How do I separate


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## butcher (Sep 6, 2017)

First how do you know the dust was gold?

If it is iron make copperas, and get gold as a byproduct (that is if there is even any gold).

Your posts, do not give us much to go on, they are like trying to answer a guessing game with no clues to what you are talking about.


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