Non-Chemical Gold tarnish problem

[mr-fixit]

My dearest Palladium, are you saying when I melted the 24k on the stainless there was mutual exchange, some of the stainless is in the gold and some of the gold is in the stainless? If so this I did not realise. I was told that molten gold acts like a magnet so I presumed there was no gold loss and only a slight contamination of the gold from the stainless. So are you saying that 8% of the gold is in the dish and 8% of the dish is in the gold? If you know what I mean.

I melted 1g of 24k in a stainless steel dish to form a globule to use as currency. After the globule cooled down it weighed 1g but is now 22k. I presumed the contamination of the gold must very slight because there is no increase in weight (scales 0.01), but enough to register the gold as 22k ie the golds purity is less than 999.

I am getting confused.

But hey what do I know about gold refining?

My aim is to rectify my mistake and not to rip-off anyone.

 

[Geo]

actually it takes very little contamination to lower karat gold purity and there's no guaranty that the gold purity is that low. depending on the test used. if you would simply refine the gold im sure you would not lose any appreciable weight unless you lose it in another way such as leaving beads in the melting dish or blowing powder out of the dish with the torch. it takes a very sophisticated process to guaranty purity so either send the gold to be refined and sent back or take your chances and do it your self but theres no magic fix. i lost 20+ grams of gold to a simple mistake a couple of days ago and theres no magic solution to reclaim it. pull it together and refine your gold and make your buttons. it was a simple mistake and not one you are likely to repeat.

 

[Harold_V]

are you saying when I melted the 24k on the stainless there was mutual exchange, some of the stainless is in the gold and some of the gold is in the stainless?

That's correct! You should know and understand that molten metals are strong solvents of other metals. You need not melt one in the other---it will dissolve, much the way sugar dissolves in water. So then, the chance that the gold you melted remains pure is not good. Not good at all.

Wise people do not melt precious metals in metallic vessels of any description.

Harold

 

[mr-fixit]

Ive re-melted a button in a well Boraxed ceramic melting dish 4 times and it has turned out spotless, no tarnish or dicolouration just a shiny round button with a little dimple on top. What does this mean?

 

[Palladium]

Good deal. How about a pic?

 

[Harold_V]

Ive re-melted a button in a well Boraxed ceramic melting dish 4 times and it has turned out spotless, no tarnish or dicolouration just a shiny round button with a little dimple on top. What does this mean?

I'd assume it means the gold is pure. Melting and re-melting makes no difference so long as there are no base metals present to oxidize. Note that I'm assuming that the button you speak of is not submerged in borax when molten, but is exposed to atmosphere. If it is submerged, the shiny surface is meaningless. However, in that case, the color of the flux remaining can be an indicator of purity. It should remain free of color, or be colored nothing more than pink or (light) purple.

The dimple you speak of tends to be a feature that is representative of pure gold. It's referenced as a *pipe*. It can be eliminated by controlled freezing, but those that know and understand gold look for the pipe to bolster the claim of pure gold. A frosty surface of a button is also a sign of less than pure gold.

Harold

 

[philddreamer]

If I may share a couple of pic's, one of a 24k button with a "pipe" & one 17.52k without; also notice the "frost".

 

[mr-fixit]

Twas to good to be true. When I re-melt the buttons the tarnish re-appears. So the button have not magically cleansed themselves. When the button was molten I noticed dancing stuff on the surface, presumably contaminant, after about 30 seconds or so this stuff would make its way downwards and presumably in to the borax? I thought if repeated this process I could clean the button, apparently not. But what I did notice was if I put a low flame on a tarnished button the tarnish disappears, until its remelted. The pipe in the photo is not the same as my buttons, mine are more evenly rounded holes.