I have heard that Borax can be used as flux, but I have also read that in Aluminum it is really not that necessary to use a flux.



As I understand it the goal is to keep the air from contacting the molten metal. In the case of aluminum, skimming off the slag is enough to get you a very good aluminum pour. Experts say don't stir it, because that causes gas to get in.



Aluminum is easier and safer than casting iron.



For a crucible and charcoal I found that the thinner steel pots work better, because you can heat them up quicker with not so much fuel and energy. We tried using an actual ceramic crucible we got from a donation but we never got it to heat up enough to do anything! So we went for the thinner walled steel pot.



Once we can get more energy output then we can use the ceramic crucible, was my hypothesis.



We also opted for making ingots first, and getting familiar with the process, then later on we can do more interesting things.



One thing that helped a lot was: Start with am ore solid piece of aluminum, wait to get a nice pool of molten aluminum and then put in cans and anything else that is more thin. Once you get the pool of metal, everything else gets easier.