Non-Chemical could the crucible be too large for the kiln

[whoLady]

Hi, I have a kiln I made for melting metals and it uses propane.
I've had some good luck melting copper, brass, and gold so far.
But I wanted a bigger crucible than what I had, for larger pours. The one I ordered I'm afraid may be too big for the inside of my kiln. It leaves enough room for me to get my tongs onto it to lift it out, but JUST enough. I wondered if this makes it too close to where the flame is coming in, can the flame be very close to the crucible with no ill effects?

Thanks

 

[kurtak]

Hi, I have a kiln I made for melting metals and it uses propane.

Thanks

It's actually a "furnace" not a kiln

Kiln's usually have electric elements & are designed for baking pottery & usually not made to reach temps for melting metals

A picture of the crucible in the furnace & picture out of the furnace would help in getting an answer

Kurt

 

[nickvc]

If the crucible is too large it will probably stop the flame from swirling round it and if it’s directed straight at it it will wear the crucible at the point it hits.

 

[whoLady]

If the crucible is too large it will probably stop the flame from swirling round it and if it’s directed straight at it it will wear the crucible at the point it hits.

Thanks, this is what I was worried about. I do think the flame is swirling around, it does come out the top nicely still, but I do worry the crucible could be worn more at the point of contact. Frankly though, the flame hits any crucible I put in there obviously, I just wondered if too close was bad.

I will try to post pix as kurt suggested.

 

[whoLady]

It's actually a "furnace" not a kiln....

A picture of the crucible in the furnace & picture out of the furnace would help in getting an answer

Thank you, I am new to this and don't have the terminology right sometimes. It does make googling for answers easier when using the right terms. :wink:
I will try to post pix, I'm sure that would help.

 

[nickton]

I think that if it fits in there it's not too big. Actually a worse problem would be if the furnace were too big-it would be a waste of heat. I noticed that a tight space was ideal for concentrating a flame. If your material does not fill the larger crucible then you should use a smaller one however.

Just my opinion.

 

[Shark]

You need a minimum of 3/4 of an inch from the widest part of the crucible to the furnace wall for most smaller furnaces. While they will work with 1/2 inch clearance there is a noticeable reduction in performance. My little furnace works best with a crucible that will hold 2 pounds of material (brass I think is the way it is rated). I can fit the next size larger crucible, but it never melts any more material weight wise, and what does melt rarely ever pours very well.