Did you buy or make your own favorite crucible? Have you used one with a spout that lets you pour the metal from the bottom of the crucible? If it matters I am looking to melt AL and brass in an electric lab size heat treat oven.
I don't think bottom pour crucibles are worth the trouble or cost, especially just for aluminum. I prefer Morgan Salamander Super Clay Graphite crucibles for all around use and value, but if it's dedicated aluminum duty, Silicon Carbide might produce slightly better melt times. Best, Kelly
you may want to rethink the Brass!!! heating that slow you will have horrible amount of off-gassing of the Zinc, which of course will give you a fume issue, change the composition of the metal, and absolutely Filthify the interior of the oven, for Brass to work well it needs to be melted FAST- in truth all that has to be fast is from molten to pouring temp, so you can do some sort of jeweler tricks and heat in the oven up to pouring then go to direct flame to get to pouring , like silver smiths often do, at least on instagram V/r HT1
Super Salamanders are hard to beat. I have some small volume home made ones that I use for aluminum, only because they fit in my small electric furnace. <<< My avatar is a Super Salamander with brass.
I have clay-graphite crucibles as well and a few Salamanders, but most just Amazon / fleabay ones which do well. Long ago (yes, in 1972 !) when I started metalcasting I used welded stainless steel crucibles for melting copper, but after two uses they started leaking so I switched to clay graphite. On Youtube there are some vids where the user uses (stainless) steel crucibles with the same issues: leaking. The copper or brass dissolves the steel slowly. For aluminum I sometimes do use steel cans which is OK.
For Fuel furnaces (non-Induction) melting high temp + 1100 C. you can't beat an iso-pressed Ceramic bonded SiC or a carbon bonded SiC crucible. At the elevated temperatures the speed of melting comes from the increased density and the high thermal conductivity of the crucible and the heat transfer on the crucible wall at the upper temperatures. Depending on alloys produced/fluxes used will depend on how much erosion/ thinning of side wall and therefore lifetime the crucible will see. The Salamander Super brand is all round performer for alum and Cu alloys, however crucible melt time on high temps maybe a little longer, and there are improved products out there, however how available they are in smaller sizes in you in your home markets, and the price you will pay will depend on other factors commercial in nature and whether products is stocked locally.
I melt Everdur. I love Starrbide crucibles. I have a Starrbide #8 i have used for years for god knows how many melts. It seems to be indestructible. It still shows no signs of deterioration. Richard
Rich The Starrbide of old was made in CT USA by Amercian Crucible and Refractory Co, which was a tar based carbon bonded SiC roller formed crucible. Morgan purchased ARCC around later 90-earlier 2000's and ran business for few years, however the plant was run down and needed large investments to stabilise the cost base and those oil kilns weren't very efficient. Therefore plant was closed, and UK plant got upgrades for global market, and the Starrbide brand was transferred to Morgan Germany where a similar product was being made under Nolte/Morgan Stabil. Therefore, this is what's floating around the world now, well in fact mainly USA market. Over the years all these brands have been tweaked a little and some more than others to keep the technology flowing into product and boosting the Morgan brand cheers Brett
