So I want to pick up some more crucibles. I measured the one that came with my furnace and it's roughly the size of an #10. I'm wondering if I should go down to a #8 or #6 though? My furnace bore is roughly 8 inches with a height of 11 inches. The Morgan salamander seems to be the gold standard for crucibles. 130 bucks for an A10 though. The A6 is only 60 which is a little better. I've heard several mentions of the legend budget crucibles on here. They are only 30 bucks. Obviously the don't last as long, but are they that bad? I hear a lot about flame impingement, but can someone detail that a little better for me. The way my furnace is built the crucible is in the flame, but it's not straight on its across the side. Is that ok?
I’ve bought all of my crucibles from Legend. I’ve bought quite a few of their “budget” crucibles and have had good success if you’re limiting to aluminum. You will get several dozen melts at least, probably more. Graduating to copper alloys will require Salamander Super at least. https://www.lmine.com/product-categ...ucibles/salamander-super-a-premium-crucibles/ Unless you’re casting tiny stuff, I wouldn’t go smaller than a #8 or you’ll end up with regrets. You’ll want to fill your crucible pretty close to full as a general practice, so you don’t want to go too large with your go-to crucible, but running out of metal during a pour can awfully demoralizing. Just ask any one of us. We all have a story. You can always pour off the excess. I have 8s and 10s in Salamander Super (bronze and cast iron) and a 16 budget graphite for aluminum. You really don’t want the flame directly hitting your crucible if you can help it. Let the plinth take the beating. If youre getting some impingement even after elevating the crucible, just try not to place the crucible in the same position all of the time. You don’t need any more than a couple of inches below the lid. Pete
I bought a #8 Starrbide years ago, have melted many pots of Everdur in it, and it is still as good as new. I blast it with an oil burner and it doesn't seem to care. I bought 3 Chinese clay graphite crucibles from Budget Casting Supply many years ago: 2 #8's and a # 40. The #8's cracked almost immediately. The #40, which actually measures as a #30, has stuck with me. (Those Chinese crucibles are a crap-shoot like Harbor Freight tools.) I try not to use the large crucible except when necessary. I pour single handed with the assistance of a gantry crane I built, but still, 80 or 90 pounds of molten bronze in a Chinese crucible is nothing to take lightly. Especially now that I'm 81 years old. I would rather pour my sculptures in 20 pound pieces and weld them together. Richard
There might be something to be said for using cheap crucibles if you're just starting out and still learning how to tune your furnace. That way if you burn one or two up before it's time getting your settings dialed in, at least it won't cost you a fortune. Especially if you have one of those affordable hobby furnace kits where the burner is aimed almost directly at the crucible (yes even if it's more over to one side). If you have one of those, maybe you can raise your crucible above that direct flame impingement with a taller plinth as suggested. I find it worthwhile to buy crucibles from reputable brands like Morgan and make an effort to take good care of them, but I won't turn my nose up at mystery hand me down crucibles when offered. But it's a mixed bag, I've retired a crucible that produced over 100 castings over 6 years and still looked pretty good but felt super light and sounded sketchy, and kept another in service that looked awful after just a handful of melts, but felt and sounded solid and intact. Both A6's, my go-to size for most casting sessions. To me tiny vs huge has a more to do with what kind of castings you want to make and how many at a time, and how much molten metal you're comfortable handling. I usually grab a size 12 most times when the A6 isn't enough, but I'd go bigger more often if I had the room and a reason to lay down more molds at a time. Jeff
