Talkin’ about foundry stuf
With aluminum, what works best for me is old castings. Sometimes though, those are few between. My solution is to bump up the silica levels with some ground glass. Clear is best, and I haven’t tried anything other than that and brown bottle glass. I would imagine the colors burn out, but it would be interesting to see what blue glass does to the color of the aluminum. I tried the clean play sand and it just seemed to sink to the bottom and do nothing. The glass is a finer powder and ‘dissolves’ better.
Yes, it makes it harder on the tools later, when I am machining the parts, but it doesn’t seem any worse that working the harder steels. (Obviously not machine steels. Those get ground, not cut.)
When I made my little steam engine, I didn’t have any cast parts to add to the melt: just slugs of already processed pop cans. Stuff that I had melted down and burned off the paint and plastics. It’s tough stuff, bit feels ‘gooey’ when its getting cut. It will gum up a file with a quickness too. Adding a tablespoon of ground glass and stirring the melt for a bit before the pour seemed to get rid of that gooey nature. It also brought more dross to the surface. I also put in some pool shock; about a tablespoon full, as well and that definitely cleaned up the melt.(fair warning, do this with GREAT caution, the fumes will, WILL kill you if you get caught in them. I won’t tell you the whole ‘apply only in a well ventilated area’ cuz ya’d best be out in the open working with this stuff anyways.)
By the way, that is why I have those graphite rods. I use them to stir the melt. They eventually burn up, but it takes awhile.
A little trick for working with brass. Add a handful of matchheads to the melt before scraping the dross. It helps bring up the dross and makes the melt flow better. It may darken the brass a little because you are adding phosphorous to it, essentially making phosphor bronze, but thats the fun of this: learning as you go what works and how, so later you know even more. I haven’t tried tje matches with the aluminum but it would definitely change the alloy; I just don’t know how. When I have the shop finished, that will be another project for me, just to see.
Anywhoos, its Sunday and that means laundry day so I’ll chat atcha’ll later.