Thread: Phosphate Opal
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Old 12-05-2006, 04:06 AM
Hugh Jenkins Hugh Jenkins is offline
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John, Great to read your contribution on this. Devit and phospate concentration are the main issues. But from experience in melting, the flame settings did make a lot of difference. One reason that most clear batches cannot be made into phospate opals is the presence of antimony. Since antimony acts as an oxygen absorber in the cooling phase, it can reduce certain less stable oxides. Identical oxide formulas without antimony were way more successful. Keeping the phosphate down in the 4 to 4.5% range gives beautiful results.
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