# is clay/ silica dish a one shot deal?



## ssstew2000 (Nov 28, 2010)

Its finished, it worked. and Im a beleiver now .it was just small scale, and the gold button does'nt even show on the gram scale. Thats ok i can still see it and it was just a test run anyway. Question is the clay/silica melting dishIi used still has the borax and the purple residue stuck to it. I tried re-melting it but could not get it to flow out. Is there a way to clean this out so i can reuse the dish or can i just reuse it as is. thanks again every one this is a great hobbie. :mrgreen: :lol: :shock: :mrgreen: 
stepehn.


----------



## Barren Realms 007 (Nov 28, 2010)

You can use soda ash to make the flux flow easier, it will deteriorate the crucible each time you use it.


----------



## lazersteve (Nov 28, 2010)

Use the search box for 'cleaning dish' and you will find a detailed step by step description of the process. I believe there is a direct link to the dish cleaning topic in the Rough Guide to the forum also (found via the Guided Tour Link below). Harold originally posted on this and I posted a numerical step-by-step process using his method.

Steve


----------



## Harold_V (Nov 29, 2010)

ssstew2000 said:


> Its finished, it worked. and Im a beleiver now .it was just small scale, and the gold button does'nt even show on the gram scale. Thats ok i can still see it and it was just a test run anyway. Question is the clay/silica melting dishIi used still has the borax and the purple residue stuck to it. I tried re-melting it but could not get it to flow out. Is there a way to clean this out so i can reuse the dish or can i just reuse it as is.


A melting dish that has been properly seasoned and shows signs of purple is generally not in need of any attention. It's just a sign of some colloidal gold being included in the flux. 

I'm assuming that the flux covering isn't heavy, just a light film over the surface, and it doesn't have any other colors (brown, dark green, etc.). I am also assuming that you have used ONLY borax for flux, nothing more. If that be the case, simply use the dish for the next melting of pure, or, if you intend to do any inquarting, use it as is for that purpose. 

Cleaning melting dishes can be beneficial, but at the cost of a considerable amount of their useful life. For that reason, I recommend you use a melting dish until the flux covering becomes contaminated to the point where it is no longer fluid at heat. As it darkens, a function of absorbing oxides from melting base metals, it will become less and less fluid. At that point, follow the cleaning instructions mentioned. A cone mold is very desirable to have when you clean a melting dish, for in the process of dissolving the hardened flux, you will see metals form that you swear weren't there. By pouring the hot slag to a cone mold, the bead of metal that is produced will be found at the tip of the cone, and is readily separated from the slag. This bead should yield values when refined. 

Harold


----------



## Oz (Nov 29, 2010)

Here is a picture I took of one of my crucibles that I only use for fine gold (.999 fine or better). A new dish will start off with a pink color then gradually get to a purple as it is used. It is not much gold shown in this dish, but it is worth recovering (as Irons says "everything but the squeal"). My concern is that you have used a new melting dish or crucible and produced a button that is less than a gram, yet you are seeing a purple color on your dish. That would indicate to me that you are using too much heat and volatilizing off more than normal amounts of your gold to the air. Metals boil just like water does, and some of those vapors become lost at too great a heat.

Show us a picture and we will be in a better position to help you.


----------



## ssstew2000 (Nov 29, 2010)

Now that is a reply thank you so much .I believe to much heat might be the problem. I will take photos of my crucible and the button I produced. Thank you so much. PS I used compressed oxy and propane. 8) 
Stephen


----------



## ssstew2000 (Nov 29, 2010)

here are the pics of my crucible and speck of gold


----------



## goldenchild (Nov 29, 2010)

Does anyone know the breakdown of how collodial gold is formed when melting? I had a crucible that I melted in only once and it left very deep violet behind. Just wondering why sometimes its faint and sometimes its very dark. I will post a the pic if I can dig it up.

Found them:


----------



## butcher (Nov 30, 2010)

Just my guess too high heat in a chloride (chlorine gas under heat)(fumes carrying gold) rich enviroment vaporizing the gold, maybe lowering the heat until the chlorides are driven off from powders,then raising heat to melt, but not too hot. I also guess these fume's are trapped in the fluxcoating. which can also be mixed impurity (base metal oxide) in the gold mixed with these oxide's in flux coating on crucible.
again just a guess. :?:


----------

