imsmooth Posted October 25, 2011 Share Posted October 25, 2011 I have been playing with my induction forge seen here. I have been heating smaller piece in a crucible of furnace cement. The problem is the cement has a limit of about 2000F and starts to fuse, contaminating the molten iron. What else can I use for containing the molten iron? Is there another type of cement or clay like Hessian? Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted October 25, 2011 Share Posted October 25, 2011 I am not sure what crucibles have to do with your topic title. You may not get many posters. Until then read about casting you may get a few ideas, why reinvent the wheel? many crucibles available for various uses. FYI the Japanese use a clay lined furnace to partially melt the sands they used in making tamahagane and their clays melted also, imparting some trace elements to the steels. Worked well for them in that instance. Quote Link to comment Share on other sites More sharing options...
Fosterob Posted October 25, 2011 Share Posted October 25, 2011 So how do you use that to measure temperature?? Rob Quote Link to comment Share on other sites More sharing options...
WmHorus Posted October 25, 2011 Share Posted October 25, 2011 Induction is cool, but How safe is having molten steel drip out of your makeshift crucible onto the floor near those electrical cords we saw at the top of the video...... Quote Link to comment Share on other sites More sharing options...
Fosterob Posted October 25, 2011 Share Posted October 25, 2011 Thanks for adding the video, it makes more sense now. You have built a nice machine there, congratulations. Rob Quote Link to comment Share on other sites More sharing options...
Fosterob Posted October 25, 2011 Share Posted October 25, 2011 Induction is cool, but How safe is having molten steel drip out of your makeshift crucible onto the floor near those electrical cords we saw at the top of the video...... What are you talking about?? I saw no evidence of molten steel dripping on electrical cords. Rob Quote Link to comment Share on other sites More sharing options...
WmHorus Posted October 25, 2011 Share Posted October 25, 2011 The reason I mentioned anything is because of the open HOLE in the crucible where you can see the ground, I asked a question I did not call names or attack the guy. I actually think induction forges are interesting, Slag and 'sparkies' dripping from an open hole just concerned me for his safety. And no I dont call myself a blacksmith or much of anything else, I have thought about smelting and melting metals here and there, but it takes a few more specialized items I don't have at this moment. I have 2 electrical wires into my 'tent' One to my PH the other is for the blower on my gas forge, and the LP is kept far away from the forge. As far as MY paranoia towards safety I dont work when its been raining for a while do to muddy conditions as well as not wanting to get electrocuted accidentally. And living where I do and working outside it leaves only very short windows to do much between raindrops, but when it snows I do more since the ground is usually dry in my tent then. Quote Link to comment Share on other sites More sharing options...
Fosterob Posted October 25, 2011 Share Posted October 25, 2011 I think the point of his original post was where to get or how to make a "real" cruicible. People who know more about casting should know the answer to that. Rob Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted October 25, 2011 Share Posted October 25, 2011 I see it also, it starts about 2:30 into this then gets more serious around 3:00. and before that shows cords all over. If you dont care about safety that is your business, but dont slam the more serious members here for using their brains, and not expect a reply... Also dripping molten metal is not just a sparkle, its a sign of burning the metal Quote Link to comment Share on other sites More sharing options...
WmHorus Posted October 25, 2011 Share Posted October 25, 2011 There are several places online to find crucibles to use...they can range in size and price from 30-40 bucks to alot more depending on size and material used to make it. http://www.graphitestore.com/ http://www.kingsleynorth.com/skshop/products.php?catID=263 Just a couple places, not the cheapest ones I know but they can be found for less if you dig hard enough, just remember cheaper sometimes is not always better. Quote Link to comment Share on other sites More sharing options...
Fosterob Posted October 25, 2011 Share Posted October 25, 2011 It is good to be safety oriented. Rob Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted October 25, 2011 Share Posted October 25, 2011 First the OP posted this thread in the general smithing section, It was moved here afterward. Second he labeled this with the title of " A great way to measure temp.." ; which this has nothing to do with this video at all, and third he is using a dangerous container for this experiment, 4th no flux or other way to prevent oxidation This " experimenting " point to his not being familiar with this forum, general safety, or commonly accepted methods for the melting of metals, as well as fact that he has not done much of any searching on his own, else he would have noticed we have information warning of some of these mistakes, before he committed them. All of this is very dangerous, and since you missed it, he does have molten drips coming from his melting clay, if you re-read my last post and the location times. So perhaps staff should re name this thread to "a great way to hurt people"? Quote Link to comment Share on other sites More sharing options...
imsmooth Posted October 26, 2011 Author Share Posted October 26, 2011 I need to reply to a few remarks. First, I agree with safety. I wear welders gloves and a face shield. Two, there is only one power cord and it is far from the molten metal. Most of the "cords" seen are water cooling hoses, and they too are not near the path of the sparks. I have been using this for several years and it is fine. Three, there is no crucible: it is a billet being held by a solid rod. I was asking about the crucible because I have also liquifed metal and want a better way to contain it. The ones that I have bought have all shattered from thermal shock. Finally, the title is a mistake. I was going to post something else, and then I left the computer. When I came back to finish the post I was thinking about crucibles and wrote about this subject. I only realized the mistake the next day. Sorry about that one. I actually have a great way to measure the temperature, but I will release that information in a few days. It is inexpensive and has reasonable accuracy. Quote Link to comment Share on other sites More sharing options...
WmHorus Posted October 26, 2011 Share Posted October 26, 2011 What type of crucibles were you using and why were you having issues with Thermal shock? Obviously rapid cool down but were you quenching something or allowing it to cool down on its own? And Thank you for clearing the cords issue up, with all the different devices you had there it looked like there were more. I have been wanting to make my own steel ( besides forgewelding ) for quite some time now, and eventually I might get to that point. I was just worried about splatter hitting yer cables and causing more problems. This is a suggestion wear chest protection if you are going to mess with molten metal, bad things can happen and the thought of just a tshirt .....*shudders* Quote Link to comment Share on other sites More sharing options...
imsmooth Posted October 26, 2011 Author Share Posted October 26, 2011 I was using fused quartz and zirconia crucibles. I would have the metal in a molten state and I didn't want to let the unit run for a hour as I progressively cooled down. Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted October 26, 2011 Share Posted October 26, 2011 I'm a smith, not a founder. You say, "molten iron." Is it iron? Are you breaking up gray cast iron, as old radiators, floor drain plates, etc.? Are you fluxing? Or are you just putting any old steel in the crucible and hoping for a liquid, pourable, melt. My understanding is that remelting gray cast iron is the route to go, because it has the right composition for melting. My smithing students often burn A36 steel by accident when forging. When that happens, the oxygen in the fire and atmosphere "attack" the metal in an uncontrolled manner. The surface and sometimes the interior of the bar get oxidized. Occasionally, a bar will separate into two pieces. We get lots of sparks coming off the burnt metal. An old horseshoer friend says, "It looks like the rats have been chewing on it!" If we put the same mild steel in a crucible (graphite?) and heat it over our coal forge, wouldn't we still obtain an uncontrolled mess when it gets above say, 2,600ºF? Quote Link to comment Share on other sites More sharing options...
MattBower Posted October 26, 2011 Share Posted October 26, 2011 Silicon carbide has exceptional thermal shock resistance. Graphite is even better. Unfortunately they're both susceptors -- i.e., induction will cause them both to heat directly, which could be a problem. They'll both also contribute carbon to any ferrous metals you melt. Still, they might be worth a try. But please do this over a bed of dry sand large and deep enough to capture the results of any failures. Molten metal plus concrete is a very dangerous combination. Quote Link to comment Share on other sites More sharing options...
MattBower Posted October 26, 2011 Share Posted October 26, 2011 If we put the same mild steel in a crucible (graphite?) and heat it over our coal forge, wouldn't we still obtain an uncontrolled mess when it gets above say, 2,600ºF? In an oxidizing atmosphere, yes. In a reducing atmosphere, we'll get steel with an ever-increasing proportion of carbon, until it becomes cast iron. Cover fluxes (e.g., crushed glass) are normally used for this reason. Quote Link to comment Share on other sites More sharing options...
imsmooth Posted October 31, 2011 Author Share Posted October 31, 2011 I found my answer. I called Hercules, which makes the cement I've been using. It states that it is rated for 2300F, but can go to 2550F. This, of course, melts and disolves into my molten steel. I found a company that makes cement rated for 3000F. It is retort furnace cement. I am going to buy some in the very near future and see what happens. Quote Link to comment Share on other sites More sharing options...
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