Jim
Member
Is the process of making gold shot just pouring off molten gold slowly into water after you've heated it? Or do you do it all at once? Whats the purpose of making gold shot instead of ingots ect.
Gold Shot?
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Gold shot is not created by pouring from the lip of a container. It must be discharged through a nozzle. You can make a simple one by drilling a small hole (1/8") in the bottom of a melting dish, which would then be mounted over your container of water, with a torch playing on the dish, around the hole. That prevents the gold from freezing in the dish when it is transferred from the melting dish in which the gold powder is melted. For reasons that have always been hard for me to understand, that forms shot, instead of cornflakes.
For the record, I was informed of this process by a small commercial refining operation, now defunct, that used to be in Sparks, Nevada. Up to that time, my routine was to pour from the lip, always creating cornflakes. They work very well for inquartation, but leave a great deal to be desired if you package gold in visqueen packets when returning values to the customer. The cornflakes tend to have sharp edges and projections that cut the bag.
Shot is preferred by those that use gold, for it makes weighing out the desired amount easy. Wise goldsmiths don't melt a lot of gold at one time, otherwise it could lead to defective castings (gas inclusions).
By melting only the amount that is needed, the small amount left over (the sprue) can be melted with the next batch, assuring that re-melted gold doesn't accumulate.
The problem with melting gold time and again is that the base metal (typically copper, but not restricted to copper) oxidizes and begins creating gas that accumulates in tiny pockets in castings. Most every jeweler that does casting has had that experience, and often accounts for why they won't, or don't prefer to use gold that has been used previously.
Hope this helps
Harold
For the record, I was informed of this process by a small commercial refining operation, now defunct, that used to be in Sparks, Nevada. Up to that time, my routine was to pour from the lip, always creating cornflakes. They work very well for inquartation, but leave a great deal to be desired if you package gold in visqueen packets when returning values to the customer. The cornflakes tend to have sharp edges and projections that cut the bag.
Shot is preferred by those that use gold, for it makes weighing out the desired amount easy. Wise goldsmiths don't melt a lot of gold at one time, otherwise it could lead to defective castings (gas inclusions).
By melting only the amount that is needed, the small amount left over (the sprue) can be melted with the next batch, assuring that re-melted gold doesn't accumulate.
The problem with melting gold time and again is that the base metal (typically copper, but not restricted to copper) oxidizes and begins creating gas that accumulates in tiny pockets in castings. Most every jeweler that does casting has had that experience, and often accounts for why they won't, or don't prefer to use gold that has been used previously.
Hope this helps
Harold
Jim
Member
Yea,
Thanks fer the info, im thinking the 1/8 hole would have to do with surface tention and regulating the ammount or something.
But if u were using 24k pure gold, wouldnt it not matter if it is melted time and again because theres no copper ect?
o wait 18k and 14k my bad hahaha.
Thanks fer the info, im thinking the 1/8 hole would have to do with surface tention and regulating the ammount or something.
But if u were using 24k pure gold, wouldnt it not matter if it is melted time and again because theres no copper ect?
o wait 18k and 14k my bad hahaha.
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That depends on what you call 24K.
If your gold runs less than 9995, pretty good chance it will form oxides on the surface as the shot is created. The slightest discoloration from brilliant yellow is a sure sign that's the case.
Melting gold that is not pure is very telling---especially if it is heated a few times, each time forming more oxide film. You can usually tell how pure your gold is (not to be considered an assay) when you melt the stuff. If the thin film of borax that should be in your dish forms anything but a purple cast, the gold is not pure. The purple is nothing more than colloidal gold.
The off color ( green, black, brown) discoloration comes from the borax absorbing the oxides, but it's a slow process even when using an oxidizer as Hoke suggested. I tried that before I realized a second refining was needed to raise my quality. Had no luck at all, although the borax darkened. Seems it doesn't remove all of it, so the gold quality isn't improved enough to warrant the trouble.
Harold
If your gold runs less than 9995, pretty good chance it will form oxides on the surface as the shot is created. The slightest discoloration from brilliant yellow is a sure sign that's the case.
Melting gold that is not pure is very telling---especially if it is heated a few times, each time forming more oxide film. You can usually tell how pure your gold is (not to be considered an assay) when you melt the stuff. If the thin film of borax that should be in your dish forms anything but a purple cast, the gold is not pure. The purple is nothing more than colloidal gold.
The off color ( green, black, brown) discoloration comes from the borax absorbing the oxides, but it's a slow process even when using an oxidizer as Hoke suggested. I tried that before I realized a second refining was needed to raise my quality. Had no luck at all, although the borax darkened. Seems it doesn't remove all of it, so the gold quality isn't improved enough to warrant the trouble.
Harold
I don't know if roundness is much of a concern when making gold shot, But if you needed nice round balls :lol: ( Jewelry) you could do it the way they used to make lead shot for guns.
They used a shot tower. It was like 200 feet tall, they would melt lead at the top and drip it down letting it free fall the entire 200 feet into a tub of water.
The lead would ball up due it's surface tension and cool enough that it would not flatten upon impact with the water.
A friend of mine used to do it from a platform lifted up on a forklift 20 feet I guess. They would get satisfactory results.
john
They used a shot tower. It was like 200 feet tall, they would melt lead at the top and drip it down letting it free fall the entire 200 feet into a tub of water.
The lead would ball up due it's surface tension and cool enough that it would not flatten upon impact with the water.
A friend of mine used to do it from a platform lifted up on a forklift 20 feet I guess. They would get satisfactory results.
john
greentea
Active member
I used to make a lot of gold shot and I made it by placing a couple of stainless steel casting flasks ( about 2 1/2" x 4" pipe sections) one on top of the other and turning the faucet on cold full blast so that the water would pour into the flasks and roiled up violently. Then I tillted the crucible slightly with the torch keeping the melt hot and slowly dribbled the gold into the roiling water. Seemed to work pretty well for me.
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Did that process produce shot, or what I like to call cornflakes? Granulating the material, for me, wasn't a problem, but getting shot was. I had no success until I started following the advice to use an orifice. Didn't try what you recommend, however. I used to pour to a stainless container, deep, maybe 14". With the orifice, great results.greentea said:
Harold
greentea
Active member
I guess I should try it again to make sure - it was a long time ago. If my memory serves me correctly, the shot was spherical. The water was really cold and moving furiously about trying to escape the inside of the flasks. I don't do any of that type of work anymore so maybe someone else can try it out if they want to.
We made the shot commercially. We had a gas pot furnace with a hole cut in the bottom. The crucible, in the furnace, had several holes drilled in the bottom of it. I think we used a #56 drill bit. The furnace was elevated above a round stainless tank about 3' to 3.5' deep and 15" in diameter. A water inlet, fed by a pump and set at an angle in the bottom of the tank, allowed the water to swirl from the bottom up. The water then overflowed through an overflow hose to a tank and was recirculated through the pump. We put 1 or 2, 1000 oz bars in the crucible at one time. The shot was almost perfect spheres, between 1/8" and 3/16" in diameter. It was collected in a SS mesh basket, resting near the bottom of the tank.
