View Details ok but when i have melted aluminium in it it did not eat the sainless steel I have a plan to make a crucidle that would be made with ceramic slip and sand. Goto well to know more. I used to retort mercury, which was extracted from old dental amalgam. I had built my retort from stainless and found that I had to line the retort with thin asbestos, otherwise the mercury was slowly dissolving the retort where it came in contact in liquid form. Surprisingly, there seemed to be no negative effect elsewhere, but I attribute that to the fact that the stainless may have been too cool to be effected. Only at the bottom, where I super heated the retort, was there any signs of deterioration, and even there it was slow to appear. I'm of the opinion that your stainless is slowly going the same direction, but I may be wrong. None of the books I've read on foundry practice encourage the use of metal melting vessels, and for contamination reasons. Again, that my or may not be an issue with you and your projects. It would be a death knell if you did any certified casting work, but then that is generally beyond the realm of the home shop type, anyway.I'll be interested in hearing how this project turns out. I've used more than my share of clay melting dishes, which are very unstable, especially when first used. If they are not completely dried before taking to melting temperature, you're almost assured of a broken dish. I get the idea your slip idea will have similar results. The problem with most materials that could be used is they don't have any strength. Silicon carbide crucibles become relatively soft and pliable when heated, so they have a tendency to not crack as a result. It's quite easy to deform one when it's hot if it has been worn thin, such as when a lot of flux has been used.My concern would be breaking the crucible when it's up to heat, bad in the furnace, but much worse when you're attempting to handle the crucible. Talk about some toasty feet!After researching methods for parting copper electrolytically, I went against current convention and made a refining cell from ceramic slip. It was a dreadful amount of work which required a large Plaster of Paris mold. The first attempt turned out more like a canoe than a cell, and the second, while somewhat better, was much the same. [img]/ubb/images/graemlins/frown.gif"%20alt="[/img]The real bad payback for all my efforts came when I operated the canoe shaped cell. It ran fine for the first few hours, so I left it running and went to bed for the day. The next morning when I awoke I found the cell in two pieces, with the electrolyte (sulfuric acid) spilled in the lab. Mind you, the cell held about two gallons of fluid. The succeeding fiber glass cell gave no problems. I found it was a stupid idea to re-invent the wheel. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]I'm sure you understand the ramifications of dropping molten metal on concrete. If you're working over concrete in your shop, I strongly advise a covering of sand to keep metal from intimate contact with the floor. Could prevent a steam explosion.Let us hear your results on the crucible. Very interesting.Harold
but copper did..
I used to retort mercury, which was extracted from old dental amalgam. I had built my retort from stainless and found that I had to line the retort with thin asbestos, otherwise the mercury was slowly dissolving the retort where it came in contact in liquid form. Surprisingly, there seemed to be no negative effect elsewhere, but I attribute that to the fact that the stainless may have been too cool to be effected. Only at the bottom, where I super heated the retort, was there any signs of deterioration, and even there it was slow to appear. I'm of the opinion that your stainless is slowly going the same direction, but I may be wrong. None of the books I've read on foundry practice encourage the use of metal melting vessels, and for contamination reasons. Again, that my or may not be an issue with you and your projects. It would be a death knell if you did any certified casting work, but then that is generally beyond the realm of the home shop type, anyway.
I have try just ceramic slip and it split it two. And the slip i am talking about is for ceramic molds and is melting temp is 2000f to 2400f
and the sand that i will be useing is high temp
I'll be interested in hearing how this project turns out. I've used more than my share of clay melting dishes, which are very unstable, especially when first used. If they are not completely dried before taking to melting temperature, you're almost assured of a broken dish. I get the idea your slip idea will have similar results. The problem with most materials that could be used is they don't have any strength. Silicon carbide crucibles become relatively soft and pliable when heated, so they have a tendency to not crack as a result. It's quite easy to deform one when it's hot if it has been worn thin, such as when a lot of flux has been used.
My concern would be breaking the crucible when it's up to heat, bad in the furnace, but much worse when you're attempting to handle the crucible. Talk about some toasty feet!
After researching methods for parting copper electrolytically, I went against current convention and made a refining cell from ceramic slip. It was a dreadful amount of work which required a large Plaster of Paris mold. The first attempt turned out more like a canoe than a cell, and the second, while somewhat better, was much the same. [img]/ubb/images/graemlins/frown.gif"%20alt="[/img]
The real bad payback for all my efforts came when I operated the canoe shaped cell. It ran fine for the first few hours, so I left it running and went to bed for the day. The next morning when I awoke I found the cell in two pieces, with the electrolyte (sulfuric acid) spilled in the lab. Mind you, the cell held about two gallons of fluid. The succeeding fiber glass cell gave no problems. I found it was a stupid idea to re-invent the wheel. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
I'm sure you understand the ramifications of dropping molten metal on concrete. If you're working over concrete in your shop, I strongly advise a covering of sand to keep metal from intimate contact with the floor. Could prevent a steam explosion.
Let us hear your results on the crucible. Very interesting.
Harold
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