Gas Smelter and Crucible base

[BEBailey3]

Very new to the craft here...

but, on many videos I notice some sort of base on the bottom of the smelters that the crucible is set on...is this necessary or just a good idea to help with heat distribution?

 

Also, what would the material be?  A ceramic brick or fire brick?

 

Any help appreciated!

[Steve Sells]

who uses a crucible for smelting? and why? where does the slag go?

[Latticino]

He probably means a melting furnace.  Crucible supports in those serve several purposes including the following:

1. Provide a replaceable, level, flat bottom to properly support the crucible
2. Elevate the crucible above the furnace floor to improve heat circulation and raise smaller crucibles to more easily accessible heights
3. Provide a clean, flux and old spill free surface that the crucible won't stick to (see replaceable from #1)

I'm not sure what you mean by fire brick and ceramic brick.  The crucible support needs to be able to tolerate the temperatures your furnace will experience and still support the weight of the loaded crucible.  I suspect the best option would be a high alumina refractory fire brick rated up to 3,000 deg F, but those aren't cheap.  A fire brick from your local big box hardware store won't cut it unless you are melting aluminum.

[BEBailey3]

You are correct a melting furnace, sometimes my head locks onto the wrong words. 

But yes, that is exactly what I was asking about, my wife bought me a devil forge gas melting furnace,  an been trying to prepare so I do it right. 

[Chimaera]

Hi Bailey. I think the word you are looking for may be "foundry". Melting furnace also works. Smelting is the act of turning ore into a usable product, while melting is just that. 

To answer your question: most people put a fire brick under the crucible. This helps protect the floor of the foundry, in case you spill or get flux on it. It also provides a level and easily replaceable floor. Finally, it raises it up for better heat circulation. (I'm sorry, I just saw that Latticino covered all those). To make sure your crucible doesn't stick to the firebrick, put a small piece of cardboard between them. It will turn into carbon and keep them from sticking.

[Frosty]

The term for the fire brick or whatever you use to set the crucible on is, "Plinth."

Start off small and low temp melts until you have a safe routine down. Casting is fun but inherently dangerous, one mistake can lead to a seriously B A D outcome.

Frosty The Lucky.