# Graphite Crucible broke while in Furnace



## pena4250 (May 10, 2013)

Bought a induction electric furnace from EBay $370.00 used it twice, second time for whatever there reason the graphite crucible broke in half the pics shows what stayed in the botom half, thank GOD I was able to recover it, needless to say I lost a lot of .999 pure silver I was melting around 37oz and was able to recover some, I think I lost 5 to 7oz) not to mention I ruined my brand new induction furnace. I contacted the seller, she said she was going to send me replacement parts, that was 2 months ago, the username I believe is specialtydiamond18...... I think the crucible was defected..... :evil: thats why the silver is in a cylinder form...... need to find something big to melt it down and make it io a big bar. Im new to the site, just want to intoduce myself. Lots of knowledge on this site, I melt silver and gold and use the AP process...


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## jmdlcar (May 10, 2013)

Hi,

Now that one big Silver round. It dose look nice. Let us know if you remelting it.

Thanks
Jack


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## Alentia (May 10, 2013)

Those thing suck! Long ago, I dropped crucible before I could pour metal into the water. It did hit the water eventually bottom down and everything exploded. I spent about 6 hours picking up bits and pieces of inquarted gold (about 500 grams of metal) from the floor all over the shop.

The are 3 reasons why crucible dropped:

1. My stupidity on the first place using that damn thing.
2. Graphite burns out after 5-10 uses and sunk holding ring almost flattened
3. The tongs they supply with that thing made the opposite way to what tongs suppose to be. Short handle and long arms, so you have to apply alot of power to hold it together. While normally you should have long handle and short arms, so you apply little force to clamp up on crucible.

I made all my tongs myself now and using Thermolyne oven furnace.


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## Smack (May 10, 2013)

I like clay/graphite crucibles. You know you can over clamp and break one right? Usually there should be a stop on the tongs to prevent that. Not saying that's what happened, just saying.


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## Woodworker1997 (May 11, 2013)

Smack,

Off topic, would you sell that cute dog?

Derek.


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## Smack (May 11, 2013)

haha, no. She's an only child, a one pup litter.


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## TomVader (May 11, 2013)

I have the same furnace from specialtydiamond. When it arrived I was surprised to find NO paperwork with it. No instructions, description, or catalog for replacement parts. I contacted the co. and asked them to send me some kind of manual or something. They ignored my e-mails until I filed a complaint with E-bay. Then they e-mailed me back real snotty-like "just plug it in and turn it on, what else do you want?" I doubt you'll get satisfaction from them.


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## FrugalRefiner (May 11, 2013)

pena4250 said:


> Bought a induction electric furnace from EBay $370.00.


I doubt what you bought was an induction furnace for $370.00. They're usually quite a bit more expensive. More likely you have a simple electric melt furnace.

Dave


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## pena4250 (May 11, 2013)

Yep,never buy on of those again, put them on my no buy list, the electric furnances, well the one I had was a boat anchor, more more attempt to contact diamondspecialty for the replacement parts they promised I will put them on my no buy list. And yest I do plan on melting it down when I get something big enough to do it in...... I want to pour it into a bar shape.


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## pena4250 (May 11, 2013)

Alentia said:


> Those thing suck! Long ago, I dropped crucible before I could pour metal into the water. It did hit the water eventually bottom down and everything exploded. I spent about 6 hours picking up bits and pieces of inquarted gold (about 500 grams of metal) from the floor all over the shop.
> 
> The are 3 reasons why crucible dropped:
> 
> ...




Ouch!!!!! especialy gold.....


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## kurt (May 12, 2013)

Reasons why crucibles crack &/or brake

1) did not pre-treat to drive out moisture --- new crucibles - no mater the composition they are made up of - have moisture in them --- so you need to pre-treat them by applying a warm heat to start with & SLOWLY bring the the heat up on them to drive the moisture out SLOWLY --- if you don't do this & instead apply fast high heat - the moisture will cause rapid expantion which in turn will cause cracking &/or brakage of the crucible.

If you live in an area where high humidity is a factor & your crucibles are going to sit around for extended periods of time between use - they will re-absorb moisture so you need to store them in a way to prevent this - or bring temp up slowly agian before going to melt temp --- its better to store them so they don't re-absorb moisture because allowing them to absorb moisture shortens there life span each time you have to drive the moisture out

2) also - over loading with metal (especially solid metal - not so much powders - but also powders) will crack &/or brake a crucible --- what happens here is that before you reach melt temp & while your metal is "heating" the metal starts to expand & this expantion (if your crucible is over loaded) can exert enough presure on the crucible to crack or brake it

You should start by only loading your crucible with 1/4 to 1/3 of its capacity & then ad metal to "the melt" as it melts - let each addition melt before the next addition

3) sometimes (not often) but sometimes you can get a defective crucible - which usually does not show up untill heat is applied to it --- & there is no reall way to "prove" it was defect or due to reason #1 or #2 --- so its hard to go back to the manufactor &/or supplier for replacement


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## catty5 (Oct 11, 2015)

Reasons why crucibles crack &/or brake has many factors,here is an article may helps: http://www.xrdcarbon.com/industry_news/125.html


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## MarcoP (Oct 12, 2015)

catty5 said:


> Reasons why crucibles crack &/or brake has many factors,here is an article may helps: http://www.xrdcarbon.com/industry_news/125.html


What does it means "1、When Handled it should be light up light put".

Marco


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## catty5 (Oct 12, 2015)

MarcoP said:


> catty5 said:
> 
> 
> > Reasons why crucibles crack &/or brake has many factors,here is an article may helps: http://www.xrdcarbon.com/industry_news/125.html
> ...


i think it means when the crucible moved it should be handled gently


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