Newbie question about crucible

jocat54

jocat54

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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
 
Do you have any pictures of the interior of the furnace in operation so we can see the flame path????????????;)
 
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
 
+1 for the burner position.
You need to have a swirl pattern to the flame, so that it flows around the crucible.

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

Tom
 
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
Click to expand...
 
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
 
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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