Dawnsdad said:
GSP, I just got your book is (turns out I already had it, oh well) and quickly scanned through it today. One question, on page 91, 9C says to remove the hot crucible from the furnace and fill it with damp silver crystal. I am new to all of this, but an old friend who recovered silver from x-ray processes back in the 70s warned me that introducing moisture in such a situation could have disastrous results. Can you please comment? Thanks.
I'm not Chris, but I may be able to cast a little light on this one.
While water and hot crucibles are not generally compatible, because the damp silver is open in structure, what little steam that may develop is readily discharged from the crucible. There is no risk of a steam explosion, if that is your concern. I would not recommend damp silver be added to a molten mass, however.
While I never melted wet crystals, I commonly wetted the surface of cement silver when it was introduced to the furnace. I never started with a hot crucible, however. I'd fill the crucible to near the top, and tamp well, to compact the silver, then use a wash bottle to dampen the surface, compacting yet again. My purpose was to limit dusting of the fine silver particles. It appeared to be a viable way to keep all the silver in the furnace, and caused no problems.
On that note, when melting cement silver, flux should not be added with the silver. It should be well heated and have melted considerably before adding any borax. That way, contaminants will have had the opportunity to oxidize, and none of the fine silver particles will be bound in the flux after melting. Mixing them before melting offers the risk of a percentage of the silver suspended in the flux, in particular if the flux is quite viscous.
I'm sure Chris will lend his thoughts to this matter. He may have had good reasons for making the suggestion he did. He has a serious amount of experience with silver.
Harold