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| My double weekend project - furnce+crucible |
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| NeoTech:
Hmm think i will try that.. i have couple of bags with fire briquettes.. And 60kg of the stonecoal stuff (coke?). In case of a fire.. But im afraid that can melt the steel crucible even. ;) But before that.. i need to make a molding bench, get hold of a 3-4 bags of silica sand and bentonite.. There is stuff still missing in the equation of me melting aluminium, but im getting there. |
| MetalCaster:
Nice furnace and crucible. There is a steep learning curve to the casting hobby. I am always surprised at how many in the online videos handle sodium silicate with their bare hands. I guess some guys have very tough skin on their hands. I took a very long time to dry out my furnace using a low propane flame, gradually increasing to a medium propane flame, perhaps 8 or 12 hours. Very slow process but very necessary to prevent things from exploding. And also, I have found that in the casting world, the word "wet" is anything that has not been heated by a torch or held in the furnace exhaust stream for a minute or two, such as ingot molds, charging tongs, fresh metal for chanrging the crucible, etc. I seal my non-steel crucibles in plastic bags when not in use, and heat them slowly at first to drive off any moisture. The furnace itself will absorb moisture between pours, but that will be driven off when it is fired. |
| vtsteam:
--- Quote from: NeoTech on July 20, 2013, 12:25:46 PM ---Hmm think i will try that.. i have couple of bags with fire briquettes.. And 60kg of the stonecoal stuff (coke?). In case of a fire.. But im afraid that can melt the steel crucible even. ;) --- End quote --- A nice slow charcoal fire to start, with no blast, will do a gentle job of drying out and baking your lining -- you might do this for four hours, renewing charcoal when it drops down, (no crucible). Do this to initially to fire your lining. Make sure all steaming from the lining has stopped before applying blast. Then give it a gentle blast for say another 20 minutes, then add more charcoal and your crucible, and start a melting blast. You will then have molten aluminum as well as having fired your lining. This would be a nice day long project. You don't need greensand if you don't want to cast somethng in particular. You can pour the molten aluminum into a muffin tin and make ingots. I bet almost everybody does this at first! Don't use a plastic or teflon coated tin -- use a plain steel one. Slightly rusty is okay -- the rust serves as a release agent -- or you can use talcum powder (the talc kind, not the cornstarch kind) as a release. Just a very light powder coat. Turn it upside down or wipe it out gently with something dry - to leave a very thin coat of release. Make sure there is no moisture in these tins ever. No rain drops! Or perspiration... ps. No don't use coal or coke, use barbecue charcoal for this. |
| NeoTech:
I think its even possible to get hold of a tinpan without plastic or teflon coating these days. Thats why i thought i would make greensand, so i could cast square blocks and cylinders for machining.. making billets.. =) |
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