Hi Folks, I'm just an amature at casting of metals, and would like some info about alloying copper and aluminium. When I add a piece of aluminum to the molten copper I find that there is alot of waste material that develops and makes a mess of what I am trying to do. I figure this is due to the aluminum that I am using having other elements alloyed with it and not melting at the same temperature and or the oxidation of the aluminium.
I am doing a project on ancient coins and am trying to create a bronze / brass that has a nice yellow colour or subtle variations from red copper to orange to yellow. I have had some nice pieces already but there is a lot of waste from the process so far.
I use a ceramic crucible and acetylene torch to melt with, and I melt between 200 g to 250g of copper at a time. When I add the aluminium it absorbs into the molten copper immediately but then a unmeltable slush forms. I can pour some of the mixture out and it's nice looking metal but there is almost 1/4 of the material left in the crucible that has to be scraped out. I use Borax as a flux.
Just so you know I hand engrave my own designs on steel then take the coin blanks and strike them between the dies with a 10 lbs hammer.
Any advice? any decent how too books out there?
thanks for you help :) Kyle Mutcher.