I have a question about doing more than one pour per furnace heat. So far I have been doing only one due to the fact I'm still learning. My question is if I would do, say an aluminum pour and while the furnace is still hot load another crucible into the furnace is there any chance of damage to the crucible and is it going to stick to the already hot plinth block?
Why not just return the crucible to the furnace and add to the already hot crucible? That should save energy and the puddle of unpoured metal in the bottom should help move the second and third melts along. That is the strategy I have followed. Denis
Just so it's clear you mean you do an aluminum pour, and then after you're finished you want to do a brass pour with a new crucible? If it were me, I'd have the brass crucible preheating in one of my kilns. As long as it's been tempered and has been dried/preheated I don't see anything wrong with that. Toaster oven from the thrift store maybe? 400°f is better than ambient At the least turn down the heat in your furnace in between loads and then turn it up once the new crucible is in there.
I have swapped crucibles with no issues. However I never heat ne while I'm pouring, I want to pay attention if something goes awry. I do demold once I know the next crucible is stable and heating. I glue a piece of cardboard to the cold crucible to avoid sticking. I also leave the burner off (and out for my furnace) and close the lid to retain heat. Then when I'm done pouring, open and put the new charged crucible in. Don't think I'd do it with a green crucible.
I light my furnace with my aluminum crucible in it. I start it with diesel to preheat it till it's hot enough to turn on the oil. While its preheating I start a charcoal fire in my little bucket furnace (no forced air) and set my bronze crucible on top of it right on the coals. By the time I've finished my aluminum pour the bronze crucible is too hot to pick up without a tool. That's been good enough so far. I wouldnt put it in a hot furnace cold. Pete
i regularly go back to the furnace as many as 5 time in a single day, i occasionally start with aluminum, then switch to the brass crucible , no concerns putting the cold crucible into a hot furnace as log as the crucible has been properly cured IAW the manufacturers instructions, I leave any unpoured metal in the crucible unless I'm melting nasty(painted or possibly wet) scrap in which case I ingot off the metal, and charge the crucible empty , the hot ingot geos into the crucible V/r HT1
I would warm the crucible and the charge on top of the furnace, before putting it in the furnace. Meet a bloke who cracked a crucible he had had for years, the only time he didn't pre-heat it, Cheers Charlie
