One-use or disposable crucibles
Quote from Jason Shaw on July 14, 2025, 1:04 amHello everyone, this is my first post on this forum. I see some of smiths on YouTube making wootz and a couple of them use what look to be homemade, possibly concrete, crucibles that they simply break with a hammer to extract the ingot. Does anyone know anything about these type of crucibles? Like what they're made from and how to make them? Thank you.
Hello everyone, this is my first post on this forum. I see some of smiths on YouTube making wootz and a couple of them use what look to be homemade, possibly concrete, crucibles that they simply break with a hammer to extract the ingot. Does anyone know anything about these type of crucibles? Like what they're made from and how to make them? Thank you.
Quote from Jerry Martin on July 22, 2025, 12:20 pmI believe they are using cheap clay graphite crucibles and the pucks won't usually come out. They may also be mullite crucibles but I don't think they could handle the heat. Used to be able to get those for $5 each but they have gone up. This is what I have gotten in the past for Aluminum and some bronze melting.
Legend “K” Fire Clay Crucible – Case of 16 – Legend Inc. Sparks, Nevada USA They also have some budget clay graphite ones. Just make sure of the size you want. I ordered some small ones and they are too small. I will try them anyway for some wootz, may be able to get a pound out of one.
I believe they are using cheap clay graphite crucibles and the pucks won't usually come out. They may also be mullite crucibles but I don't think they could handle the heat. Used to be able to get those for $5 each but they have gone up. This is what I have gotten in the past for Aluminum and some bronze melting.
Legend “K” Fire Clay Crucible – Case of 16 – Legend Inc. Sparks, Nevada USA They also have some budget clay graphite ones. Just make sure of the size you want. I ordered some small ones and they are too small. I will try them anyway for some wootz, may be able to get a pound out of one.
Quote from Jacob Christian on July 25, 2025, 8:32 pmIf this is what I think it is, you are likely talking about FZ knives on youtube who does indeed make his own crucibles and break each and every one of them lol.... He used to have a video on it and it was fire clay, graphite, and a filler of some type that I do not remember.
While this is a viable way of making crucibles, I would suggest using either a clay graphite crucible or silicon carbide crucible. They both have their pros and cons which I can go into if necessary.
I would suggest just buying crucibles though. They are fairly cheap and last a few firings (Many many firings if you are carful and use a skim coat of some type of fire clay). The bigger reason though is that they are going to be ready to use, and you will not have to worry about tweaking the mixture for thermal expansion. If you get it wrong, then you have to deal with molten iron everywhere.... At the temps needed to melt it, it becomes pretty much corrosive and eats through refractory like a hot knife and butter. Trust me... you absolutely do not want to have a crucible failure lol... it is an absolute nightmare and usually requires making a new furnace.
-Jacob
If this is what I think it is, you are likely talking about FZ knives on youtube who does indeed make his own crucibles and break each and every one of them lol.... He used to have a video on it and it was fire clay, graphite, and a filler of some type that I do not remember.
While this is a viable way of making crucibles, I would suggest using either a clay graphite crucible or silicon carbide crucible. They both have their pros and cons which I can go into if necessary.
I would suggest just buying crucibles though. They are fairly cheap and last a few firings (Many many firings if you are carful and use a skim coat of some type of fire clay). The bigger reason though is that they are going to be ready to use, and you will not have to worry about tweaking the mixture for thermal expansion. If you get it wrong, then you have to deal with molten iron everywhere.... At the temps needed to melt it, it becomes pretty much corrosive and eats through refractory like a hot knife and butter. Trust me... you absolutely do not want to have a crucible failure lol... it is an absolute nightmare and usually requires making a new furnace.
-Jacob
Quote from Jason Shaw on August 20, 2025, 9:02 pmYes Jacob, lol, I was referring to FZ knives. Thank you for your reply. I appreciate your advice about the crucibles. I was just looking for a little shortcut, but from what you say this isn't a shortcut I want to take a chance with. My furnace isn't much, but I built it with my own hands so I'm not going to risk it with molten iron everywhere.
Do you have any recommendations on where to buy some decent crucibles without breaking the bank? I bought 2 crucibles and both exploded while I was preheating them to burn off the moisture. Apparently they both had moisture on the inside because they both exploded like I put a bit of black powder in them.
Thank you Jacob, I really love this forum you have put together.
Yes Jacob, lol, I was referring to FZ knives. Thank you for your reply. I appreciate your advice about the crucibles. I was just looking for a little shortcut, but from what you say this isn't a shortcut I want to take a chance with. My furnace isn't much, but I built it with my own hands so I'm not going to risk it with molten iron everywhere.
Do you have any recommendations on where to buy some decent crucibles without breaking the bank? I bought 2 crucibles and both exploded while I was preheating them to burn off the moisture. Apparently they both had moisture on the inside because they both exploded like I put a bit of black powder in them.
Thank you Jacob, I really love this forum you have put together.