# Newbie question about crucible



## jocat54 (Feb 8, 2012)

Hi all, I built my first furnace and made a crucible out of 3" pipe. Did my first melt today(melting pop cans)and burnt a hole in the crucible, right where the flame from the burner hits it. 


I am thinking my burner is to hot--it starting melting the cans in about 5 minutes. It is a Oliver up wind burner and seems to work well(maybe to well). I do have an adjustable regulator but no gauge so I don't know what pressure I was running. Thoughts from anyone?


Thanks


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## bvd1940 (Feb 8, 2012)

Do you have any pictures of the interior of the furnace in operation so we can see the flame path????????????


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## Tom Griffin (Feb 8, 2012)

Normally the burner enters the furnace tangent to the wall so it swirls and creates a vortex around the crucible. You might try repositioning the burner so it's not blowing directly on the crucible.

Tom


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## 12bolts (Feb 8, 2012)

+1 for the burner position.
You need to have a swirl pattern to the flame, so that it flows around the crucible.

Cheers Phil


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## jocat54 (Feb 8, 2012)

Thanks guys, it is mounted on a tangent and swirls around.(makes all the firebricks glow red all the way around, and they look the same) It burnt the hole where the flame is touching the crucible, it's not blowing directly at it. Also on about a 1" plinth block.

I guess I need to say that my furnace is not round on the inside, it is kind of a octagon,(minus one) I made the liner from firebricks. 

Sorry no pictures at this time


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## Tom Griffin (Feb 8, 2012)

You could always invest in a graphite crucible. McMaster Carr sells them for about $22 on up, depending on size.

Tom


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## bvd1940 (Feb 9, 2012)

How much space between crucible and side of furnace? I have a 6+" crucible made out of a old oxy tank bottom with a good 2.5+" clearance around the crucible and works great:biggrin:
If your furnace is to small for the burner with to small space between the crucible and wall you will have to cut down the heat of your burner and try that IMHO.:thinking: 


jocat54 said:


> Thanks guys, it is mounted on a tangent and swirls around.(makes all the firebricks glow red all the way around, and they look the same) It burnt the hole where the flame is touching the crucible, it's not blowing directly at it. Also on about a 1" plinth block.
> 
> I guess I need to say that my furnace is not round on the inside, it is kind of a octagon,(minus one) I made the liner from firebricks.
> 
> Sorry no pictures at this time


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## Rbeckett (Feb 10, 2012)

Jocat,
This is a very interesting thread.  Would you please post the ultimate solution when you arrive at it.  I have been toying with the idea of making a furnace like that but have been concerned with other issues lately.  
Bob


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## jocat54 (Feb 10, 2012)

Well, I'm out of town for the weekend(Lindale to watch grandsons play basketball), but yesterday I cut the fire brick(soft) with a large hole saw (several cuts) and made more room around the inside and more of a circle and turned the burner down and had a successful melt of the pop cans. Took about 15 to 20 minutes to start melting instead of 5 minutes.

 I read where a lot use muffinpans for molds. Does not work for me--had to tear the muffin pan up to get them out:biggrin:. Guess I'll use sand cast for the molds.

Thanks for all the replies.


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## Charley Davidson (Feb 11, 2012)

jocat54 said:


> I read where a lot use muffinpans for molds. Does not work for me--had to tear the muffin pan up to get them out:biggrin:.
> Thanks for all the replies.



Spray them with Pam


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## jocat54 (Feb 11, 2012)

Charley Davidson said:


> Spray them with Pam



Thanks, never thought about that.


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