Non-Chemical Melted liquid gold never reach the mold

[tutorus]

Hi Refiners,
I'm pretty new in this hobby and have been trying to put melted 12K and 14K gold into a mold , but the gold get harder while dropped into the mold even though i keep the maximum torch flame over it. It looks like this way never going to make a nice Bar which is my purpose.
Once the gold is dropped into the mold I put the maximum flame on it in order to melt it and make it fit in using the mold as it was a melting dish, and guess what?
The gold can not be melted while is on graphite mold.
I have two questions:
How can I keep the gold soft enough in order to make it fill the mold properly?
Why is that the gold can't be melted while is on graphite mold and heated with torch flame at maximum ?
I would gladly appreciate any comment.
Thank you
Tutorus
I'm sorry just noticed that I am in the wrong section. Won't happen again.

 

[goldsilverpro]

Probably the mold is absorbing all your heat. You need to melt in a crucible (furnace) or a jeweler's melting dish (torch) and then pour the gold into a pre-heated mold.

 

[Noxx]

Hello Tutorus,
I have the same problem. The graphite mold absorbs all the heat from the flame and we can't melt the gold.
I haven't tried yet to pour it yet. Please post your results.

Goldsilverpro how do you pre-heat your mold while melting gold ?

Thanks

 

[lazersteve]

Noxx,

Place the prepared melting dish on top of the mold as you heat the gold. When the gold gets molten tilt the dish over 45 degrees and work the molten gold near the lip of the dish with the torch flame. Play the flame between the edge of the dish where the molten gold is and into the graphite mold. Move the flame quickly back and forth over the gold and the mold until the gold is very liquid (freely moves around the edge of the dish). This will require the torch to be set with a very hot flame to get the mold up to temperature. Once the dish edge is red hot and the mold is preheated tip the dish over into the mold and the gold will fill the mold and set quickly.

You need to have enough gold to fill the mold or you will get an incomplete bar. It takes practice , but you will get it after a few tries.

I could make a video if you like?

Steve

 

[goldsilverpro]

You preheat the mold to drive the moisture out, within a minute, or so, before you pour. Otherwise, steam can be produced, when the hot gold hits the moisture, and the gold will spit out of the mold. Both cast iron and graphite can absorb quite a bit of moisture. I use a torch. I start in the cavity, with a circular motion, and work my way out to the edge. You don't want to get the mold red hot. 30 to 60 seconds (for a small mold) is probably enough. Sometimes, on a graphite mold, you can see a color difference (between moisture and no moisture) as you work the torch out to the edge. I would GUESS you want to get the mold about 300-400C or 600-750F

 

[tutorus]

Hi Refiners,
I never tried to pre heat the mold. Only after the gold is poured i put the torch on it, and even though the mold is red hot the gold doesn't melt any more.
From now I'm going to pre heat the graphite mold and will follow with the torch gradually when pouring, placing the melting dish stick to the mold at a 45 degrees position.
Question: Do I need to do it with borax or just the gold alone?, I think that the borax gives me a cleaner gold, but it is an obstacle when pouring down.
I've been melting jewelry defective scrap.
Thank you amigos.

 

[lazersteve]

Use just enough borax to coat the dish with a very thin layer.

Steve

 

[Noxx]

Thanks for the great advices.

Steve, no need to make a video, I do understand. I know you don't have much leisure time.

Can I achieve to pour gold in an 1/4 oz. graphite ingot with acetylene torch ? (no Oxy)

 

[Harold_V]

Can I achieve to pour gold in an 1/4 oz. graphite ingot with acetylene torch ? (no Oxy)

Not likely.

Harold

 

[aflacglobal]

Noxx,Got to have ox for combustion.

 

[tutorus]

I really appreciate them. No need to place a video. Your advice was very well explained.
one more question:
1. why is not a good idea to try to pour into a 1/4 ounce mold? what is the inconvenience of not doing it in a bigger one?
Thank you,

 

[Noxx]

I want to pour it into a smaller mold because I don't handle larger gold quantities. (ex: 1 oz)

 

[tutorus]

Sorry, my question was not very specific. Like you, I have no use for a bigger mold.
so, I wonder why can not have the same melting results in a small 1/4 ounce one ?
I hope somebody advises.
Thanks

 

[lazersteve]

The reason you can't use a torch without oxygen is that it won't get hot enough to melt the gold, coupled with the heat capacity of the graphite mold, you'll be hard pressed to get favorable results.

Plus when acetylene is burned alone you get all kinds of carbon soot that really mucks thing up.

Steve