well i see different approaches here. i guess the most cost effective for the batch i have , around 10kg , is to go with graphite molds , use them a couple times only so they stay smooth, heat them vigorously before pouring, keep the molten silver temperature high, deprive as much oxygen as possible with a live flame over the pour, if possible cover the mold with a heated graphite or steel cover. Let cool in the mold to settle, up to one minute, then drop the ingot to cool in water. Am i on the right path? Will try this out when outside temperatures rise (i'm in Miami, but we're in the 40s this long weekend, a tad cold for us, lol )
Pouring Bars as Perfect as Possible
- Thread starter buckrogers1
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richmond_alan
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Yes, that's pretty much it. You'll work out how many times you can reuse the graphite moulds as you proceed.
The silver will chill very quickly once poured, (way less than a minute). Knock the bar out as soon as it sets otherwise you'll transfer too much heat into the mould.
It's not necessary to quench the ingots in water, you can let them air cool. (Water quenching is good when removing any flux coating or if the bar needs to be handled immediately.)
It's very important not to tap or knock the mould while the silver chills else the upper surface will be rough. Similarly, don't lift the cover plate while the silver is still liquid.
Hand pouring ingots is "touchy-feely" so it's difficult to consistently get perfection even with a repeated technique. If you're chasing perfection be prepared to remelt and repeat. Processing 10kg, (10 x 1kg?) will give you a good opportunity to learn
Yep, 40F sounds chilly for Miami. I'm in Tasmania and we rarely get down to that in winter. Cheers, Alan
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Dropping in cold water while still hot, can lead to a harder bar. If you cool slowly, it will be softer ( easier to stamp ).
Iron or steel are hardened bringing the metal to a cherry red and non-magnetic (rearranging crystal structure) and quenching in oil or salt brine, water is of little use as the steam gas bubble do not let water touch the iron to any extent or cool it rapidly enough to freeze the crystal structure, rapid cooling locks in the crystals structure making the iron or steal glass brittle hard (easily broken), now to soften the knife to make it hard but not brittle we clean it bright to see color reheat to a specific temperature (which can be judged by the color of the steel) and quench it to aneal or lock it into that state of hard but not brittle soft but not too soft that it bends or dulls or wears too easily...
Metals like copper silver and gold react differently than iron or steel.
These metals become work hardened, bending twisting deforming, hammering all hardening these metals
You can only hammer or bend these metals so much before they grow crystals and harden. these metals to aneal them we can bring them up to a specific temperature Usually to a barely glowing red then we quench them (usually in a copper acidic solution depending on the metal, to remove the oxide coating in the quench (oxides caused by air and the heat of the torch), thus annealing or softening process of the metal acid like copper them to soften them, so now we can beat on the silver with a hammer more to get it to shape up, we may need to re-aneal after it begins to work harden again...
Metals like copper silver and gold react differently than iron or steel.
These metals become work hardened, bending twisting deforming, hammering all hardening these metals
You can only hammer or bend these metals so much before they grow crystals and harden. these metals to aneal them we can bring them up to a specific temperature Usually to a barely glowing red then we quench them (usually in a copper acidic solution depending on the metal, to remove the oxide coating in the quench (oxides caused by air and the heat of the torch), thus annealing or softening process of the metal acid like copper them to soften them, so now we can beat on the silver with a hammer more to get it to shape up, we may need to re-aneal after it begins to work harden again...
