I have now processed my first batch of scrap material using the basic 'AR' method. Everything went extreemly well thanks to the handbook. However I have come to melting the gold into 3 bullion coins. When I melt the gold I cant seem to get a good colouration. I am using a graphite crucible that I am heating via gas furnace. I have boric acid and normall borax and have tried both. However the product seems to oxidise and turn a pink / bronze colour, and although this is very pretty I dont want to loose any product through extensive polishing. The discolouration is only a thin layer but I have seen this done and the foundries pour gold and it looks ready, besides a little polishing.
Has anybody got some advice on how to use the powders correctly, ie amounts, time of application etc. I may be putting the powder in to early or to late. I know im on the right tracks, I just have no experiance with melting gold.
As always advice would be greatly appreciated.