Fire assay question / making a button

[Asmbandits]

So I recently purchased a few bone ash cupel from a local mining supply shop and Im wondering what Im doing wrong as I cannot get the cupel to absorb the lead. I started with some fine gold and suspect black sand as a demo run, used some flux also provided by the shop and melted that down until I had what looks like lead and slag, I then collected all the lead and discarded the glass slag. I then melted all the lead into one solid button in a new cupel and heated until both cupel and leads were bright orange.. No matter how long I leave it heated the lead just sits there and does not absorb. The shop that supplied me that it would absorb the lead and that it could be done with little as a map gap torch (this is what im using)..

Here is a photo of what im working with after a few trys at heating for led absorbing..

 

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[jair]

So I recently purchased a few bone ash cupel from a local mining supply shop and Im wondering what im doing wrong as I cannot get the cupel to absorb the lead. I started with some fine gold and suspect black sand as a demo run, used some flux also provided by the shop and melted that down until I had what looks like lead and slag, I then collected all the lead and discarded the glass slag. I then melted all the lead into one solid button in a new cupel and heated until both cupel and leads were bright orange.. Mo matter how long I leave it headed the lead just sits there and does not absorb. The shop that supplied me that it would absorb the lead and that it could be done with little as a map gap torch (this is what im using).. Here is a photo of what im working with after a few trys at heating for led absorbing.. <img src="http://www.treasurenet.com/forums/attachment.php?attachmentid=1039250"/><img src="http://www.treasurenet.com/forums/attachment.php?attachmentid=1039251"/>

I do fire assay's . In an oven at 1750 for cupel's , absorbing the lead . It takes an hour aprox.

 

[jair]

I do fire assay's . In an oven at 1750 for cupel's , absorbing the lead . It takes an hour aprox.

 

[Asmbandits]

Great info, I'm thinking I need to get it hotter and for longer.. looks like I'm going to have to upgrade to kiln possibly?

 

[orotoro]

The cupel needs to be red hot or your button will "freeze". Where I work we cupel at 1850 F. If your not worried about silver loss you can cupel at much higher temps. i.e..2000F Whatever you do don't breath the lead fumes!

 

[dredgeman]

Hotter and longer

The kwik kiln is a small kiln that uses propane and works well

Canvasman on Ebay has one he makes in Or. and he is great to deal with. Both small and simple to use with propane. Get to 2100 degrees

We use regular kilns at 2100 degrees and the little ones for quick melts.

 

[golden ray]

I find that the magnesium cupels work a little better for me
then the bone ash ones. Just my experience.

 

[Asmbandits]

Yes I've looked into the kwik kiln but I can't justify the price, seems very expensive, I'm thinking I'll just make one myself. Im pretty sure I've figured out what they are made of and I have a friend that has a prottery kiln so I'm thinking of going that route. I think I'm not getting the cupel hot enough with what I'm using now.

 

[jair]

Yes I've looked into the kwik kiln but I can't justify the price, seems very expensive, I'm thinking I'll just make one myself. Im pretty sure I've figured out what they are made of and I have a friend that has a prottery kiln so I'm thinking of going that route. I think I'm not getting the cupel hot enough with what I'm using now.

mine is a 115 volt paragon kiln and I use house current or my generator . It cost around $650.