Well, First things first. In the spring if I am still interested.. the first step is to get the melting furnace. I want to try other things than just this... I would use a can with the top off, and compress as much as possible to see if too much sludge goes to the top... I have read that more air pockets (less dense).. is more oxidization. I have a lot on the go now to close before the spring... Meanwhile, I am adding to the pile of clean 6061 chips.....
Here is a question on the pour into a loaf... Is the poured aluminum in a loaf pretty much air free?
It depends on the contamination level (oils and the like) as well as on the time it spends in a molten state. The more time it sits in the crucible molten, the more gasses it picks up, and the more porous the casting is.
There are means to degass the molten aluminum, either with a plunger and some solid chems, or by aerating it with a nitrogen wand.
Depends whether you intend to machine your results, or stack them for recycling.
In the latter case, no worries. In the former, start scrounging up copper wire now, not later.
Rough process the material however you must, then use those ingots to charge a crucible, and do a de-gas, plus add a little copper wire to the mix, to make the ingots resulting, much easier to machine.
If I had a LOT of chips, I would likely build an open hearth furnace, with a tap off the lower pirtion of the reservoir, to draw off straight molten metal as can.
