Step 7: Smelting and Casting Aluminum
Okay lets get started with the smelt. Leave the blower turned off until the coals are established and have some grey ash on the surface. Turning the blower on prematurely will blow the fire out however once grey ash appears on several bricks the blower will greatly enhance the process from then on.
If you use on those charcoal starter devices with newspaper or whatever get your coals started. Otherwise remove the crucible and spray on a good dose of starter fluid. No need to go crazy, it won't help. Use the same sort of amount you would use the start the charcoal in your grill.
Light the charcoal and, holding the crucible the extended rod ends, place the crucible back into the furnace. **CAREFULLY** drop in additional briquets up to about the level of the crucible rod. Don't over pack, you can always drop in more briquets later.
Take the last two bricks and place them **CAREFLLY** on top of the furnace to form a chimney. They should be placed so that the center of the furnace forms a square framing the crucible. (see picture)
As things heat up the feedstock will begin to soften and then melt. As the metal melts addtional feedstock can be **CAREFULLY** added to the crucible. Eventually you will have either fed in all your feedstock or the level in the crucible will be "full". I wouldn't overfill the crucible, if it gets half full go with that until you a clear idea of how exactly things will go.
Dross and slag will float to the surface of the molten metal. I removed this using a long handled tea spoon. ( see picture ).
Once you have a nice crucible of silvery molten metal ( more or less ) remove the two chimney bricks from the top of the furnace. Hook the crucible rod with the coat hanger hook and lift the crucible out of the furnace. Tilt the crucible to pour the aluminum using the wood piece to lift the bottom (see picture), this approach provides pretty good control on the pour.
In this case I used a muffin tin as the mold. It was handy, worked and readily discharged the aluminum ingots in an interesting muffin shape ( sort of ). As you can see from the picture I've done two melts with this and didn't actually get a full muffin because I ran out of feedstock.