I need to cast a ring in white gold palladium 18ct. I purchased some casting grains from my suppliers and when it arrived it was yellow. I contacted them and sent it back. The replacement was also yellow, this time i was told it would go white when was polished. I went ahead and made a perfect cast, only it was atill yellow. I contacted the supplier again who said it needed coating and they said i had been sent the wrong metal. Next batch arrived, it is white but i can’t melt it. I have tried microwave kiln, bead makers kiln and Mapp gas but it has just gone into a lumpy ball. I dont know what to try next any advice please? Im in North Wales UK
Patsy
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Patsy, the last batch you were sent may be 18K (palladium alloy) white. Palladium alloy white golds are great, better than traditional nickel alloy whites, but they require a lot of heat to melt, even more heat when 18K.
Couple things may be responsible for the poor melt. First guess: Not enough (concentrated) flame heat. A typical Rosebud Tip (you may be using?) produces a broader flame. For melting a Tip that makes a more concentrated flame like the Paige Tools MX melting Tip is much better.
BTW, don’t use hydrogen when melting ‘palladium alloy’ whites. Palladium has an affinity for hydrogen causing the metal to become brittle. Stick with propane & oxygen. Hydrogen / oxygen is ideal for platinum but not for palladium or palladium alloy whites. Also, stay away from MAPP with precious metals.
Another possibility is the last batch you received was poorly, or incorrectly, alloyed causing the lumpy result.
It’s difficult to give exact answers sometimes, your case for example, without more information such as: Amount of metal, Torch used, fuel gas used, gas pressures used & oxygen source (tank or generator).
Re: ‘coating’ you mentioned… likely they mean rhodium plating. Lots of white golds are rhodium plated as a final step after any gem setting, engraving & finishing steps.
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Thank you for your advice.
Patsy
Often made my own 18K white gold with palladium and never had a problem using either oxy-acetylene or propane with oxygen. Used mini-Torch with rosebud tip. I may have been alloying smaller amounts.
Who is the supplier who twice sent the wrong material?
I have never had to plate my white golds.
Janet in Jerusalem
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