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Cast iron crucible... Pros, cons?


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#1 Forrest

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Posted 10 July 2009 - 08:06 PM

Hope this is the right place for this, if not please move it ;).
I've been keeping an eye out for a crucible as I would like to give metal casting a go at some stage, however new crucibles seem fairly expensive.
I found a cast iron crucible for sale that seems fairly large compared to stuff I have seen on Amazon.com, it turns out that it is not in usable condition which is a bit annoying <_<.
If something like this came up that was in usable condition would it be worth buying or would I be better off buying a new crucible of some other type?
If anyone is interested in an old rusty unusable crucible it can be found here-

http://cgi.ebay.com....ViewItemQQptZLH

Any advice is greatly appreciated -
Thank you all!

Edited by Forrest, 11 July 2009 - 02:02 AM.

Josh Forrest

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#2 Alan Longmire

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Posted 11 July 2009 - 08:36 AM

Several things come to mind, the first of which is that is not a crucible. It's a carpenter's glue pot. The outer pot would hold hot water, the inner pot is for hide glue, which must be kept hot while you're using it.

The other things have to do with what sort of metal you are wanting to cast. Iron crucibles are only good for low-temp things like lead, tin, zinc, and so on. You may get away with aluminum for a little while, but it will erode the iron. Bronze is out.

What do you want to cast?

#3 Forrest

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Posted 11 July 2009 - 06:24 PM

Haha wow.. that may have been a bit of a problem :lol:, thanks for letting me know.
I have a whole heap of copper sitting here that I figure could be used for bronze or brass or just as it is. I have some fire clay sitting around so I would consider making my own if it isn't too difficult, I'm guessing it would be far cheaper than purchasing one..
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#4 Greg H.

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Posted 12 July 2009 - 12:05 PM

The other things have to do with what sort of metal you are wanting to cast. Iron crucibles are only good for low-temp things like lead, tin, zinc, and so on. You may get away with aluminum for a little while, but it will erode the iron. Bronze is out.


Agreed.

There are ceramic coatings that can help prevent erosion with aluminum, and brass and bronze can be done, but your crucible needs to have a fair amount of Tungsten in it to do so and at that point you may as well buy a graphite of SiC crucible.
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