Cleaning scrap silver

:partying_face:Happy New Year​:partying_face:
Does adding borax to your crucible when melting scrap silver burn off any impurities ?
I’m not sure that all of it is .925 so I am wondering if this is the answer?
I then want to sand cast so i am looking for as good an end product of silver as possible !
Any thoughts people.
Thankyou in lieu

Hi,

My understanding is that the impurities stick to the flux scum/ slag on the surface of the melt…?…ie: when you swirl the melt in the crucible, the impurities stick to the sides of the crucible, or if you tap the crucible, impurities may rise to the surface, or if you stir the melt with a graphite rod, the flux carrying impurities will stick to the graphite rod…

is this correct?

julie

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I always keep a magnet in the scrap container and give it a shake before I use the scrap. When I do my melt, I sprinkle borax into it from an old salt shaker. Finally, I stir with a graphite rod to make sure that it is completely melted and that there aren’t stray pieces of unmelted material that shouldn’t be there. I have found steel springs from lobster clasps that I did not completely disassemble this way. Make sure that your crucible is hot, especially along the pour path. It helps to heat your mold, especially if it is closed. I usually put the mold right next to the crucible so that they share the heat while melting. If it is a closed mold, tip it just a bit. This seems to let the melt enter and the air it displaces move out easier. Oil the mold a bit too. I use 3 in 1 oil. I use delft clay and petrobond for casting depending on how much detail I need. Lots of fun. Good luck…Rob

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If the “impurities” are things that will float to the top of the melt, like old saw blades, chunks of refractory brick or metallic oxides, then sure; the flux can entrain them and help you skim them off. But it won’t do anything about the odd metals that might be mixed into your silver. If it’s not .925 and you want to stamp it as sterling, the best bet is to send it to a refiner and get metal back of a known quality.

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Sounds good Julie. Are graphite rods from jewellery suppliers?

The magnet idea is perfect as well s your other info. Thankyou🙏

Hi,

here are link to graphite rods:

6” length

12” length

https://www.ottofrei.com/Carbon-Stirring-Rods

i have made coiled wire/ wood handles to hold short rods…

julie

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