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| Buying Crucibles and other what nots. |
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| NeoTech:
Ah after clearing the briquettes out.. This was the dry run per your suggestion the loose bits of cement that got loose and loose sand in the furnace glassed together formed funny small melted pieces.. The brigquettes selfdestructed and went into a powered state when i passed what my thermometer could read. But you suggest leaving the dross in the crucible? All the vids i have seen (mostly myfordboy vids) he stirrs the melt with a small package of table salt and then skim the dross off the top. I figure i could just leave it but not seen anyone do it actyally.. i thougt of welding a small piece of steel to my crucible and make a small opening so it would act as a gate and let me pour more controlled - and leave the crap inside the crucible. I need to get hold of som protection gear though.. melting metals in shorts and sneakers isnt optimal.. But i think some kind of leather protectors will be needed i have a pair of foundry glows i use as welding glows actually. *cause the cover most of the arm* ;) |
| vtsteam:
--- Quote from: NeoTech on August 03, 2013, 10:43:50 AM ---But you suggest leaving the dross in the crucible? All the vids i have seen (mostly myfordboy vids) he stirrs the melt with a small package of table salt and then skim the dross off the top. --- End quote --- I have never used a flux with aluminum. The dross is easily skimmed off the top, so why would I want it? It isn't like iron where you have massive slag. And the reason you leave it on the top until just before pouring, when you skim, is so you don't produce more dross. It protects the molten aluminum underneath from oxygen and moisture in the atmosphere. Hot charcoal helps, too because it is hungry for oxygen and other contaminants that would otherwise go into the aluminum. Moisture in the air produces hydrogen bubbles in aluminum -- they are usually tiny, but when they are, they are present throughout the casting. Some people also add nasty chlorine compounds to aluminum to get rid of hydrogen bubbles. I don't. Stirring is the greatest cause of moisture absorption from the air, hydrogen bubbles and aluminum oxidation. People debate this point all the time -- so whatever is fun and works for you will be the thing you like the best. |
| NeoTech:
I think i will try both approaches.. making flux tablets of those salts needed isnt that big of a deal just a crap to deal with the chemistry set when you wanna melt metal. ;D |
| Ashlyn Katarzyna:
I've looked around locally and cannot get 4-6" dia steel rounds to use as crucibles. I thought about galvanized steel conduit but its pretty thin wall and doesn't take much to melt as I've already melted my air blast tube in the first firing of the furnace lid in a pit fire. The only thing that I have is 7" dia x 1/4" wall steel pipe. i'd have to cut out a plate of steel for a bottom and weld it on. Pretty thick wall for a charcoal furnace. Any other ideas before I find some square tubing to use? |
| vtsteam:
4 inch steel rounds? Are you talking about pipe, I hope? 7" crucible, melting conduit, etc: what kind of charcoal furnace is this? |
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