I’m not sure whether this is the right forum for this or whether I’m totally out to lunch. If I’m in the wrong forum please direct me to the correct one and I apologize in advance. I'm wondering if anyone is able to help. I've just started the very fascinating hobby of pouring gold and silver bars. I have done a number of silver bars so far but have noticed this white "staining" on the top of most of my bars. I'm melting the metal in a graphite crucible so was thinking that it might be graphite dust that has settled on the top. In order to try and get this staining off the bars I placed them in a rotary tumbler for 24 hours. It didn't make much difference and the staining is still there ( see attached images). All bars seem to have this same milky white staining. Anyone know what this is, how I can get rid of it and how I can prevent or lessen it in my future pours? Thanks so much for any insight. TD.
Have no idea, but it seems to be a tradition for all Canadian silver to have Milk Spots. Nice looking bars! And you have certainly chosen the right place for your question.
Great thanks for the reply. Interesting that you say Canadian silver has milk spots. I will definitely have to explore that further. I'm a total noob at refining and pouring so am very grateful for all the knowledge in these forums.
Milk spots on Canadian silver seem to be caused by Silver Chloride due to the die washing process using Hydrochloric acid and not being rinsed properly. Did you use anything with chlorine to wash the crucibles? Ammonia or hydrochloric acid maybe?
Are you heating up the moulds before pouring. Always pays to have a low blowtorch working the bars once poured to gain some nice effects or cooling rings to the bar
2006+ ??? not sure when it started, got milk spots, the older ones no spot they use milk to wash the blanks, when they dry...milky coins
I am heating the molds before pouring and leave the torch going while pouring. I agree - it seems to give some grand effects when the bar cools. Some of these cool effects are being obscured by what I'm starting to believe, is graphite dust. Thanks for your response.
first question is what are u using for your stock ???? and what flux ???? try to get in contact with this guy: firebird bullion he has a few "utub" videos and has posted here in the past..
I'm using 999 shot and no flux. I have actually managed to contact FB bullion and am going to be watching his videos on YT. Thanks for the response.
Since you are going to melt and pour again, see if it is coating that can be scratched off. Than you can work out it is just some oxides or “dross” Also you need to get some Borax as flux https://www.walmart.ca/en/ip/20-mule-team-borax-laundry-booster-184-kg/6000103124845 Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate Also are you melting 999 or jewellery silver like sterling?
.9999 shot never pours with an outcome like that Make sure you have not contaminated your crucible, your silver is from a reliable source.Run it thru a pickle bath after pouring that may be the simplest solution. I pour and mix all blends of silver from .9999 to .958 to .925 to recycled argentium I produce my own solder so I have seen the results of many different pours. I tend to align with Ian Gilman I agree there is the strong possibility of contamination with Silver Chloride particles, where I couldn't guess, airborne, surface ,3rd party product? The only time I have reproduced that type of effect is during refining when I have contaminated the beaker with tap water in cleaning and the surface of the silver being refined takes on the same look as your bar.This is mitigated by heating the acid solution so presents no problem at this stage.
