crucible/ cuple alternative?

[whsnare]

Working with seriously limited funds here. Does anyone know of an inexpensive crucible that can be used? ie: porcelain dish of some kind. drilled out fire brick?

also, if trying to do a fire assay is there a good alternative to a cuple? would the potato method absorb the litharge (lead oxide)?

and all of this scan be done with either a torch or furnace which i have on hand. all thoughts are welcome. I am not worried about losing values so open to suggestions.

 

[Barren Realms 007]

A piece of wook hollwed out of a clay flower pot that does not have a hole in the bottom. Some people have even gotten graphite crucibles at large retail stores sold as flower pot's, but they crack a lot.

 

[whsnare]

I had wondered that, but if it is not made of a fire clay will it still withstand 1800 degrees Celsius? If so that would be great as they are easy to come by.

 

[whsnare]

also, does anyone know of a litharge or lead oxide substitute?

 

[butcher]

Consider the ingredients in fire clays (or home made melting container) and your melt can have a chemical reaction with what you melt metals in, example silica can act as an oxidizer, sheet rock can be used to melt in but the sulfate will collect silver and other base metals, I have melted unrefined gold in home made refractory crucibles, and have had base metals react with crucible in the flux, wood can be used to melt in but charcoal form is a reducer and can change oxidized base metals to elemental metal, you can make your own bone ash cupels,
cupels and melting dish's are not that expensive, and will give the best results.

Other metals can act as a collector like litharge, and there are several oxidizers that can serve the same function in the melt.

 

[whsnare]

Consider the ingredients in fire clays (or home made melting container) and your melt can have a chemical reaction with what you melt metals in, example silica can act as an oxidizer, sheet rock can be used to melt in but the sulfate will collect silver and other base metals, I have melted unrefined gold in home made refractory crucibles, and have had base metals react with crucible in the flux, wood can be used to melt in but charcoal form is a reducer and can change oxidized base metals to elemental metal, you can make your own bone ash cupels,
cupels and melting dish's are not that expensive, and will give the best results.

Other metals can act as a collector like litharge, and there are several oxidizers that can serve the same function in the melt.

good info there Butcher, thanks. May have to give the home made version a shot. would be nice to be able to make them up when i need um, and getting rid of the base metals would be great. fighting Iron, zinc, chromium and magnesium currently.

could i get you to list me the oxidizers most commonly used as a collector in the melt?

thanks again,
WHsnare

 

[qst42know]

Here is a crucible making video I came across. Pretty low tech but quite clever. I especially like his kiln bellows.

http://www.youtube.com/watch?v=E3my6-nxFjM

 

[Oz]

You may wish to consider just how inexpensive crucibles are when you buy them retail compared to alternatives. I am the first to try to save a buck, but if a makeshift crucible fails and you have molten gold scattered as BBs and shot as a result, how much money did you save?

 

[qst42know]

If nothing else from the video remember the ring test.

It's a simple way to detect hidden cracks and avoid undesirable surprises. Tapped lightly sound vessels should ring.

 

[whsnare]

If nothing else from the video remember the ring test.

It's a simple way to detect hidden cracks and avoid undesirable surprises. Tapped lightly sound vessels should ring.

nice, thanks for shooting that video over. love the simplicity. that will come in handy.

 

[qst42know]

Homemade cupels are easier to trust due to their shape. Plain portland cement makes a serviceable cupel.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=5650&hilit=portland+cement