Cool, thanks for the heads up. I only plan on doing Aluminum, copper and maybe bronze. So I guess I will see how long it lasts. Already looking at ordering a couple more reputable ones as I knew going in the furnace I was getting was going to be comprised predominantly of that very questionable element.... "Chinesium".
That Chinese crucible will be fine for aluminum and it sounds like you’ve done your due diligence in preparing it. They don’t fare as well at higher temps, even brass or bronze. My experience has been the same as Marks. I buy my crucibles from Legend Mining in Sparks Nevada. They have low cost crucibles like what you have. They’re ok for Aluminum but they will eventually crap out after many melts. I’ve had damage and actual failure with them with bronze so I started using the more expensive Salamander Super from Legend with excellent results, including cast iron. Pete
Interesting I have 4 of the cheapest crucibles from amazon, #1, 2x#2 and a #4 and they all tempered good. If it’s white it probably didn’t get hot enough. If you use a kiln make sure you put it on ash or some cardboard. It will take long enough to hit 1100C that the glass from the molten silicon can slowly drip down and form a puddle. Let it cool in the chamber and you’ll wake up to a fused crucible and have to reheat to about 950 to be gooey enough to remove. I always take mine out once hot and let them cool on a fire brick.
If you're not aiming for iron temps then a silicon carbide crucible will be resistant to oxidation and chemical attack from fluxes and slag. Silicon carbide is soluble in iron and the crucibles have a lower service temperature.
